Patent Publication Number: US-11644833-B2

Title: Self-driving vehicle systems and methods

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
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     The entire contents of the following application are incorporated by reference herein: U.S. patent application Ser. No. 16/178,392; filed Nov. 1, 2018; and entitled SELF-DRIVING VEHICLE SYSTEMS AND METHODS. 
     The entire contents of the following application are incorporated by reference herein: U.S. patent application Ser. No. 16/372,915; filed Apr. 2, 2019; and entitled SELF-DRIVING VEHICLE SYSTEMS AND METHODS. 
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     BACKGROUND 
     Field 
     Various embodiments disclosed herein relate to vehicles. Certain embodiments relate to self-driving vehicles. 
     Description of Related Art 
     Vehicles typically require a driver. These vehicles often can only perform actions when directly steered by the driver. However, self-driving vehicles are not reliant upon drivers and can perform actions based upon particular events. Self-driving vehicles can dramatically increase travel safety and convenience. As a result, there is a need for systems and methods that enable self-driving vehicles to perform actions based upon particular events. 
     SUMMARY 
     Self-driving vehicles will save tens of thousands of lives per year. The majority of vehicle-related deaths are caused by driver error. Tests have shown that self-driving vehicles nearly eliminate self-inflicted accidents (although they are not immune to accidents caused by human drivers of other vehicles). Self-driving vehicles have unlimited attention spans and can process complex sensor data nearly instantaneously. The ability of self-driving vehicles to save lives is so impressive that society has a moral imperative to develop self-driving technology such that it can be widely adopted. 
     Self-driving vehicles also have the ability to dramatically save time and improve convenience in roadway travel. Specifically, self-driving vehicles have unlimited potential to learn and predict human behavior and perform actions accordingly. Some embodiments enable a self-driving vehicle to monitor human activity and predict when and where the human will be located and whether the human needs a ride from the self-driving vehicle. Self-driving vehicles will be able to perform such tasks with incredible efficacy and accuracy that will allow self-driving vehicles to proliferate at a much faster rate than would otherwise be the case. 
     Some embodiments comprise a maintenance system configured to be used with a self-driving vehicle. In some embodiments, maintenance systems comprise a camera system coupled to an interior of the vehicle. The camera system can be configured to take a picture of an item left behind by a first rider. Maintenance systems can comprise a vehicle management system configured to autonomously drive the vehicle to a first location to remove the item. 
     In some embodiments, the camera system comprises a first camera coupled to a ceiling of the vehicle and directed towards a first row of the vehicle, and the camera system comprises a second camera coupled to the ceiling of the vehicle and directed towards a second row of the vehicle. 
     In some embodiments, the camera system comprises a first camera coupled to a rear-view mirror of the vehicle and directed towards a first row of the vehicle, and the camera system comprises a second camera coupled to a ceiling of the vehicle and directed towards a second row of the vehicle. 
     In some embodiments, the camera system comprises a first camera located in a trunk area of the vehicle such that the first camera is configured to enable an image analysis system to determine if the item is left in the trunk area. 
     In some embodiments, the maintenance system comprises an image analysis system configured to detect the item left behind by comparing a first baseline image taken by the camera system of the interior of the vehicle to a second image taken by the camera system after the first baseline image. 
     In some embodiments, the vehicle management system is configured to automatically drive the vehicle to the first location to remove the item in response to the image analysis system detecting the item left by the first rider. 
     Some embodiments comprise a communication system configured to send a first wireless communication to a remote computing device associated with the first rider in response to the image analysis system detecting the item left behind by the first rider. The first wireless communication can be configured to notify the first rider that the item was left behind. 
     In some embodiments, the communication system is configured to send a second wireless communication comprising a third image of the item to the remote computing device in response to the image analysis system detecting the item left behind by the first rider. The third image can enable the rider to see the item on a display of her remote computing device. 
     In some embodiments, the vehicle management system is configured to receive an address of the first location from the remote computing device in response to the communication system sending the first wireless communication. 
     In some embodiments, the first location is an address at which the first rider has requested to pick up the item. The address can be the rider&#39;s current address. The address can also be a location at which the rider is not currently located by at which the rider (or the rider&#39;s representative) plans to meet the vehicle (or another vehicle carrying the item) to retrieve the item. 
     In some embodiments, the communication system is configured to receive a third wireless communication from the remote computing device associated with the first rider in response to the communication system sending the first wireless communication. The third wireless communication can comprise instructions for shipping the item. 
     In some embodiments, the first location is a shipping location (such as a FedEx, UPS, or USPS facility) configured to remove the item from the vehicle and configured to ship the item according to the shipping instructions. The vehicle management system can be configured to enable removing the item from the vehicle once the vehicle is located at the shipping location. 
     In some embodiments, the vehicle management system is configured to receive the first location of a service area configured to clean the vehicle. The vehicle management system can be configured to drive the vehicle to the service area to remove the item in response to the image analysis system detecting the item left by the first rider. 
     Some embodiments comprise a third image taken by the camera system in response to the vehicle leaving the service area. Some embodiments comprise a communication system configured to send a first wireless communication comprising the third image to a remote computing device associated with a manager of the vehicle. The first wireless communication can be configured to enable the manager to verify that the item was removed from the vehicle. 
     Some embodiments comprise a third image taken by the camera system. The image analysis system can be configured to compare the third image to the second image to detect that the item was removed from the vehicle. 
     In some embodiments, the vehicle management system is configured to fine an account of the first rider in response to the image analysis system detecting the item left behind by the first rider. 
     In some embodiments, a communication system is configured to send a first wireless communication to a remote computing device associated with the first rider in response to the image analysis system detecting the item left behind by the first rider. The first wireless communication can comprise a third image taken by the camera system. The third image can be configured to show the item. The first wireless communication can be configured to ask the first rider if the item belongs to the first rider. The communication system can be configured to receive a second wireless communication from the remote computing device in response to the first wireless communication. The second wireless communication can be configured to inform the maintenance system that the first rider is an owner of the item. The maintenance system can comprise a memory configured to record that the first rider is the owner of the item. 
     In some embodiments, the maintenance system comprises a location detection system configured to receive the first location of a remote computing device associated with the first rider to enable the vehicle management system to autonomously drive the vehicle to the first location in response to an image analysis system detecting the item left by the first rider. 
     In some embodiments, the maintenance system comprises an image analysis system configured to detect the item left behind by comparing a first baseline image taken by the camera system of the interior of the vehicle to a second image (of the interior) taken by the camera system after the first baseline image. 
     In some embodiments, the maintenance system comprises a communication system having an antenna, a transmitter, and a receiver. The communication system can be configured to send a first wireless communication to a remote computing device associated with a manager of the vehicle in response to the image analysis system detecting the item left behind by the first rider. 
     In some embodiments, the first wireless communication is configured to notify the manager that the item was left behind. The communication system can be configured to send a second wireless communication comprising a third image of the item to the remote computing device in response to the image analysis system detecting the item left behind by the first rider. 
     In some embodiments, the vehicle management system is configured to receive a third wireless communication from the remote computing device in response to the communication system sending the first wireless communication. The third second wireless communication can be configured to instruct the vehicle management system to autonomously drive the vehicle to the first location to remove the item. 
     In some embodiments, the vehicle management system is configured to determine that the first rider has exited the vehicle. The vehicle management system can be configured to cause the camera system to take a first interior image of the interior of the vehicle in response to determining that the first rider has exited the vehicle. 
     In some embodiments, the maintenance system further comprises an image analysis system having at least one processor and a memory comprising program instructions (e.g., code modules configured to be executed by one or more computers) that when executed by the at least one processor are configured to cause the image analysis system to detect the item left behind by analyzing the first interior image taken by the camera system after the first rider has exited the vehicle. The first location can be a vehicle cleaning facility. The vehicle management system can be configured to drive the vehicle to the vehicle cleaning facility to remove the item in response to the image analysis system detecting the item. 
     In some embodiments, the vehicle management system comprises a first mode and a second mode. In the first mode, the vehicle management system can be configured to make the vehicle available to accept a pick-up request of a second rider. In the second mode, the vehicle management system can be configured to make the vehicle unavailable to accept the pick-up request. The vehicle management system can be configured to be in the second mode from a first time at which the image analysis system detects the item left behind. The vehicle management system can be configured to exit the second mode and enter the first mode in response to at least one of the item being removed, receiving an indication that the vehicle has been cleaned, and the vehicle leaving a vehicle cleaning station. 
     In some embodiments, the vehicle management system is configured to determine that the first rider has exited the vehicle in response to (1) receiving a location of a remote computing device associated with the first rider and determining that the location is not inside the vehicle, (2) failing to detect a direct wireless communication from the remote computing device to an antenna of the vehicle, (3) determining, by the image analysis system, that a second interior image does not show the first rider, and/or (4) determining, by the image analysis system, that an infrared 
     image of the interior of the vehicle does not show the first rider. In some embodiments, the maintenance system comprises at least one processor and a memory comprising program instructions that when executed by the at least one processor cause the maintenance system to (1) compare a first baseline image taken by the camera system of the interior of the vehicle to a second image taken by the camera system after the first baseline image to detect the item left behind by the first rider, and/or (2) drive, by the vehicle management system, the vehicle to the first location to remove the item in response to the detecting the item. The program instructions can comprise code modules configured to be executed by one or more computers located in the vehicle and/or located away from the vehicle. 
     In some embodiments, the first location is a first vehicle cleaning facility. The program instructions can be configured to select the first vehicle cleaning facility based at least in part on determining a distance from the vehicle to the first vehicle cleaning facility and/or based at least in part on determining that the first vehicle cleaning facility is approved by a manager of the vehicle. The memory can comprise a list of vehicle cleaning facilities that were approved by the manager of the vehicle. The program instructions can be configured to choose a cleaning facility that was previously approved by the manager and is located near the current location of the vehicle. 
     In some embodiments, the program instructions are configured to send a first wireless communication to a remote computing device associated with the first rider in response to detecting the item. The first wireless communication can comprise an image of the item. The program instructions can be configured to receive a second wireless communication from the remote computing device in response to sending the first wireless communication. The second wireless communication can comprise an instruction (e.g., from the first rider) to return the item. The program instructions can be configured to drive, by the vehicle management system, the vehicle to the first location in response to the instruction. 
     Some embodiments comprise a maintenance system configured to be used with a self-driving vehicle. A maintenance system can comprise a smoke detection system configured to detect smoke inside a cabin of the vehicle; a communication system configured to send a first wireless communication to a remote computing device associated with a manager of the vehicle in response to the smoke detection system detecting the smoke; and/or a vehicle management system configured to autonomously drive the vehicle. 
     In some embodiments, a maintenance system comprises a memory having an identification of a first rider of the vehicle. The communication system can comprise an antenna, a transmitter, and/or a receiver. The communication system can be configured to send the identification of the first rider to the remote computing device of the manager in response to the smoke detection system detecting the smoke inside the vehicle. 
     In some embodiments, a maintenance system comprises a camera system coupled to an interior of the vehicle. The camera system can be configured to take a picture of a first rider smoking. The communication system can be configured to send the picture of the first rider smoking to the remote computing device. 
     In some embodiments, the camera system comprises a first camera directed towards a first row of the vehicle. The first camera can be configured to take the picture in response to the smoke detection system detecting the smoke inside the vehicle. 
     In some embodiments, the smoke detection system comprises a camera system and an image analysis system configured to detect the smoke inside the vehicle by comparing a first baseline image taken by the camera system of an interior of the vehicle to a second image taken by the camera system (of the interior of the vehicle) after the first baseline image. 
     In some embodiments, the smoke detection system comprises an ionization smoke detector configured to detect cigarette smoking. The smoke detection system can also comprise an optical smoke detector configured to detect electronic cigarette aerosol by analyzing a particle size of the aerosol and determining that the particle size is indicative of electronic cigarette use. 
     In some embodiments, the smoke detection system comprises at least one optical smoke detector configured to analyze a particle size of the smoke. The communication system is configured to send the first wireless communication identifying the smoke as an aerosol in response to the smoke detection system determining that the particle size is greater than a predetermined threshold. The communication system can be configured to send the first wireless communication identifying the smoke as cigarette smoking in response to the smoke detection system determining that the particle size is less than the predetermined threshold. 
     In some embodiments, a camera system is coupled to an interior of the vehicle. The camera system can be configured to take a picture of a first rider smoking. The communication system can be configured to send the picture of the first rider smoking to the remote computing device. The first wireless communication can be configured to enable the remote computing device to display the picture of the first rider smoking and to display an indication of whether the smoke is due to the aerosol or the cigarette smoking. 
     In some embodiments, the vehicle management system comprises a motor configured to roll down a window of the vehicle. The vehicle management system can be configured to use the motor to automatically roll down the window in response to the smoke detection system detecting the smoke inside the vehicle. 
     In some embodiments, the vehicle management system comprises a ventilation system having a fan to push air in the cabin. The fan can be located inside the dash of the vehicle such that the fan pushes air in the cabin by pushing air through a vent and into the cabin. The vehicle management system can be configured to automatically increase a rate at which the ventilation system pushes outside air into the cabin of the vehicle in response to the smoke detection system detecting the smoke inside the vehicle. In several embodiments, the rate is increased by increasing a rotational speed of the fan. 
     In some embodiments, the vehicle management system comprises a temperature management system having a thermometer and having at least one of an air conditioner, a heater, and a ventilation system having a fan to circulate air in the cabin. The fan can be located inside a vent inside the dash of the vehicle such that the fan is configured to circulate air in the cabin by pushing air out from a vent. The vehicle management system can be configured to at least one of increase and decrease an ambient temperature inside the cabin by at least ten degrees Fahrenheit in response to the smoke detection system detecting the smoke inside the vehicle to decrease a comfort level of a first rider. 
     In some embodiments, the vehicle management system is configured to decrease an ambient temperature inside the cabin by at least ten degrees Fahrenheit and/or by at least twenty degrees Fahrenheit in response to the smoke detection system detecting the smoke inside the vehicle to decrease a comfort level of a first rider. The vehicle management system can be configured to increase an ambient temperature inside the cabin by at least ten degrees Fahrenheit and/or by at least twenty degrees Fahrenheit in response to the smoke detection system detecting the smoke inside the vehicle to decrease a comfort level of a first rider. 
     In some embodiments, the vehicle management system is configured to determine a local speed limit and is configured to automatically reduce a speed of the vehicle below the local speed limit in response to the smoke detection system detecting the smoke inside the vehicle. Some embodiments include reducing the speed so much that the vehicle stops (e.g., such that the vehicle is parked). The vehicle management system can be configured to determine a suitable parking location in response to the smoke detection system detecting the smoke inside the vehicle, and the vehicle management system can be configured to park the vehicle in the parking location in response to the smoke detection system detecting the smoke inside the vehicle. 
     In some embodiments, the vehicle management system comprises a speaker. The speaker can be configured to emit audio commands instructing a first rider of the vehicle to cease smoking in order to cause the vehicle management system to increase the speed and/or start moving again after being stopped in a parking location. 
     In some embodiments, the vehicle is configured to drive a first rider to a destination selected by the first rider. The vehicle management system can be configured to cease driving towards the destination in response to the smoke detection system detecting the smoke inside the vehicle. The vehicle management system can be configured to continue driving towards the destination in response to the smoke detection system no longer detecting the smoke inside the vehicle. 
     In some embodiments, the vehicle management system is configured to fine an account of a first rider of the vehicle in response to the smoke detection system detecting the smoke inside the vehicle. The smoke detection system can be configured to analyze a particle size of the smoke to determine if the particle size is larger than a predetermined threshold. The vehicle management system can be configured to fine the account a first amount if the particle size is larger than the predetermined threshold. The vehicle management system can be configured to fine the account a second amount if the particle size is smaller than the predetermined threshold. The second amount can be larger than the first amount and/or at least 20 percent larger than the first amount. 
     In some embodiments, the vehicle management system comprises a lighting system having at least one light coupled to an interior of the vehicle. The lighting system can be configured to illuminate at least one of a seat of the vehicle and a majority of the cabin. The vehicle management system can be configured to use the lighting system to illuminate at least one of the seat and the majority of the cabin in response to the smoke detection system detecting the smoke inside the vehicle. 
     In some embodiments, the vehicle management system comprises a speaker. The speaker can be configured to emit audio commands instructing a first rider of the vehicle to cease smoking. The vehicle management system can be configured to cease illuminating the majority of the cabin in response to the smoke detection system no longer detecting the smoke inside the vehicle. 
     In some embodiments, the vehicle management system is configured to receive a first location of a service area configured to clean the vehicle. The vehicle management system can be configured to drive the vehicle to the service area in response to the smoke detection system detecting the smoke inside the vehicle. 
     In some embodiments, the smoke detection system is configured to detect the smoke emitted by a first rider while the vehicle is driving to a drop off location of the first rider. The vehicle management system can comprise a first mode and a second mode. In the first mode, the vehicle management system is configured to make the vehicle available to accept a pick-up request of a second rider. In the second mode, the vehicle management system is configured to make the vehicle unavailable to accept the pick-up request. The vehicle management system can be configured to enter the second mode in response to the smoke detection system detecting the smoke inside the vehicle. The vehicle management system can be configured to exit the second mode and enter the first mode in response to at least one of receiving an indication that the vehicle has been cleaned and the vehicle leaving a vehicle cleaning station. 
     In some embodiments, the vehicle management system comprises a ventilation system having a fan to push air in the cabin. The fan can be embedded in a vent channel of the dash or can be located in any other suitable location. The smoke detection system can be configured to analyze a particle size of the smoke to determine if the particle size is smaller than a predetermined threshold. The vehicle management system can be configured to automatically increase a rate at which the ventilation system pushes outside air into the cabin in response to the smoke detection system detecting the smoke inside the vehicle. The vehicle management system can be configured to drive the vehicle to a service area configured to clean the vehicle in response to determining that the particle size is smaller than the predetermined threshold. 
     In some embodiments, the vehicle management system comprises a motor configured to roll down a window of the vehicle. The smoke detection system is configured to analyze a particle size of the smoke to determine if the particle size is smaller than a predetermined threshold. The vehicle management system can be configured to use the motor to automatically roll down the window in response to the smoke detection system detecting the smoke inside the vehicle. The vehicle management system can be configured to drive the vehicle to a service area configured to clean the vehicle in response to determining that the particle size is smaller than the predetermined threshold. 
     In some embodiments, the vehicle management system comprises at least one of a motor configured to roll down a window of the vehicle and a ventilation system having a fan to push air in the cabin. The smoke detection system can be configured to detect the smoke emitted by a first rider while the vehicle is driving to a drop off location of the first rider. The smoke detection system can be configured to analyze a particle size of the smoke to determine if the particle size is smaller than a predetermined threshold. 
     In some embodiments, in response to the smoke detection system detecting the smoke inside the vehicle, the vehicle management system is configured to at least one of use the motor to automatically roll down the window and increase a rate at which the ventilation system pushes the air into the cabin. 
     In some embodiments, in response to determining that the particle size is larger than the predetermined threshold and after at least one of rolling down the window and increasing the rate, the vehicle management system is configured to make the vehicle available to pick up a second rider. 
     In some embodiments, in response to determining that the particle size is smaller than the predetermined threshold, the vehicle management system is configured to make the vehicle unavailable to pick up the second rider until after the vehicle management system has driven the vehicle to a service area configured to clean the vehicle. 
     In some embodiments, the vehicle management system comprises a motor configured to roll down a window of the vehicle and a rain sensor configured to detect an indication of rain on the vehicle. The smoke detection system can be configured to analyze a particle size of the smoke to determine if the particle size is smaller than a predetermined threshold. The vehicle management system can be configured to use the motor to automatically roll down the window in response to the smoke detection system detecting the smoke inside the vehicle and/or in response to the rain sensor not detecting the indication of the rain. The vehicle management system can be configured to drive the vehicle to a service area configured to clean the vehicle in response to determining that the particle size is smaller than the predetermined threshold. 
     In some embodiments, the vehicle management system comprises a motor configured to roll down a window of the vehicle and a rain sensor configured to detect an indication of rain on the vehicle. The vehicle management system can be configured to use the motor to automatically roll down the window in response to the smoke detection system detecting the smoke inside the vehicle and in response to the rain sensor not detecting the indication of the rain. 
     In some embodiments, a maintenance system is configured to be used with a self-driving vehicle. A maintenance system can comprise a smoke detection system coupled to the vehicle and configured to detect smoke inside a cabin of the vehicle. A maintenance system can comprise a vehicle management system configured to autonomously drive the vehicle. 
     In some embodiments, the vehicle management system is configured to intentionally increase a travel time of the vehicle in response to the smoke detection system detecting the smoke inside the vehicle. 
     In some embodiments, the vehicle management system is configured to increase the travel time by changing from a first travel route to a destination (e.g., a destination chosen by a first rider) to a second travel route to the destination. The vehicle management system can be configured to change from the first travel route to the second travel route to intentionally increase the travel time in response to the smoke detection system detecting the smoke inside the vehicle. 
     In some embodiments, the vehicle management system comprises at least one of a speaker and a display screen. At least one of the speaker and the display screen can be configured to provide at least one of audio instructions and visual instructions to a first rider in the vehicle. At least one of the audio instructions and the visual instructions can be configured to warn the first rider to cease smoking to avoid increasing the travel time. 
     In some embodiments, the vehicle management system comprises at least one of a speaker and a display screen. At least one of the speaker and the display screen is configured to provide at least one of audio instructions and visual instructions to a first rider. At least one of the audio instructions and the visual instructions can be configured to instruct the first rider to cease smoking in order to decrease the travel time. 
     In some embodiments, the maintenance system comprises at least one processor and at least one memory having program instructions that when executed by the at least one processor are configured to cause the vehicle management system to increase the travel time of the vehicle in response to the smoke detection system detecting the smoke inside the vehicle. 
     In some embodiments, the vehicle management system is configured to reduce a speed of the vehicle in response to the smoke detection system detecting the smoke inside the vehicle. 
     In some embodiments, in response to the smoke detection system detecting the smoke inside the vehicle, the vehicle management system is configured to automatically reduce the speed while still enabling the vehicle to continue transporting a first rider toward a destination selected by the first rider. 
     In some embodiments, the vehicle management system is configured to determine a local speed limit. The vehicle management system can be configured to intentionally reduce the speed of the vehicle to a velocity below the local speed limit and above five miles per hour (and/or above ten miles per hour) in response to the smoke detection system detecting the smoke inside the vehicle. 
     In some embodiments, the maintenance system comprises at least one processor and at least one memory having program instructions that when executed by the at least one processor are configured to cause the vehicle management system to intentionally reduce the speed of the vehicle to a velocity below a local speed limit and above five miles per hour in response to the smoke detection system detecting the smoke inside the vehicle. 
     In some embodiments, the vehicle management system comprises at least one of a speaker and a display screen. At least one of the speaker and the display screen can be configured to provide at least one of audio instructions and visual instructions to a first rider. At least one of the audio instructions and the visual instructions can be configured to instruct the first rider to cease smoking in order to increase the speed. 
     In some embodiments, the smoke detection system is configured to analyze a particle size of the smoke to determine if the particle size is smaller than a predetermined threshold. The vehicle management system can be configured to reduce the speed in response to the maintenance system detecting the smoke inside the vehicle and determining that the particle size is smaller than the predetermined threshold. 
     In some embodiments, the maintenance system is configured to detect smoke from a rider smoking inside the vehicle and/or is configured to detect smoke from a fire inside the vehicle. A vehicle can be configured to drive a first rider to a destination chosen by the first rider. The vehicle management system can be configured to cease driving toward the destination in response to the smoke detection system detecting the smoke inside the vehicle. 
     In some embodiments, the maintenance system comprises at least one processor and at least one memory having program instructions that when executed by the at least one processor are configured (to cause the vehicle management system) to cause the vehicle to cease driving toward the destination in response to the smoke detection system detecting the smoke inside the vehicle. 
     In some embodiments, the smoke detection system is configured to analyze a particle size of the smoke to determine if the particle size is smaller than a predetermined threshold. The vehicle management system can be configured to cease driving toward the destination in response to the maintenance system detecting the smoke inside the vehicle and determining that the particle size is smaller than the predetermined threshold. The vehicle can stop moving, pull over to a parking location alongside the road, and/or stop at a cleaning facility configured to remove the smoke smell from the vehicle. 
     In some embodiments, the vehicle management system is configured to cease driving in response to the maintenance system detecting the smoke inside the vehicle and determining that a concentration of the smoke exceeds a predetermined threshold. The concentration threshold can be configured to be indicative of smoke from a fire rather than smoke from smoking a cigarette or vaping. 
     In some embodiments, the maintenance system comprises at least one processor and at least one memory having program instructions that when executed by the at least one processor are configured to cause the vehicle to stop moving via (e.g., by) a first stopping mode in response to the smoke detection system detecting the smoke inside the vehicle. The program instructions can be configured to cause the vehicle to stop moving via (e.g., by) a second stopping mode in response to the smoke detection system detecting the smoke inside the vehicle and the maintenance system detecting an indication of a person being located inside the vehicle. The second stopping mode can be configured to enable the vehicle to stop more quickly than the first stopping mode. 
     In some embodiments, the second stopping mode is configured to enable the vehicle to move at a greater speed than the first stopping mode. 
     In some embodiments, the vehicle management system is configured to determine a local speed limit, and the second stopping mode is configured to enable the vehicle to exceed the local speed limit by a greater amount than the first stopping mode. 
     In some embodiments, the second stopping mode is configured to enable the vehicle to accelerate faster than the first stopping mode. 
     In some embodiments, the second stopping mode is configured to enable the vehicle to decelerate faster than the first stopping mode. 
     In some embodiments, the vehicle is configured to drive on a road. The vehicle management system can comprise a vehicle guidance system having at least one of a camera, a radar, and a lidar. The vehicle guidance system can be configured to detect objects located outside the vehicle on the road. Program instructions can be configured to enable the vehicle to come closer to the objects in the second stopping mode than in the first stopping mode. 
     In some embodiments, the vehicle management system comprises a vehicle guidance system having at least one of a camera, a radar, and a lidar. The vehicle guidance system can be configured to detect objects located outside the vehicle on the road. The maintenance system can comprise at least one processor and at least one memory having program instructions configured to be executed by the at least one processor and comprising a first mode, a second mode, and a third mode. In the first mode, the program instructions are configured to prompt the vehicle management system to drive the vehicle toward a location (e.g., a destination, a drop-off location, a pick-up location). 
     In some embodiments, the program instructions are configured to exit the first mode and enter the second mode in response to the smoke detection system detecting the smoke inside the vehicle and in response to the maintenance system determining that a person is not located inside the vehicle. In the second mode, the program instructions prompt the vehicle guidance system to implement a first stopping mode. 
     In some embodiments, the program instructions are configured to exit the first mode and enter the third mode in response to the smoke detection system detecting the smoke inside the vehicle and the maintenance system determining that the person is located inside the vehicle. In the third mode, the program instructions prompt the vehicle guidance system to implement a second stopping mode configured to enable the vehicle to come to a stop in less time than the first stopping mode. 
     In some embodiments, the vehicle management system comprises a speaker configured to emit an audio command. The audio command can be configured to instruct the first rider to cease smoking in order to resume driving toward the destination. 
     In some embodiments, the vehicle management system comprises a display screen. The display screen can be configured to provide visual instructions to the first rider. The visual instructions can be configured to instruct the first rider to cease smoking in order to resume driving toward the destination. 
     In some embodiments, the vehicle management system is configured to resume driving toward the destination in response to at least one of the smoke detection system no longer detecting the smoke and the smoke detection system detecting a decrease in a concentration of the smoke. 
     In some embodiments, the smoke detection system is configured to analyze a particle size of the smoke inside the vehicle. The maintenance system can comprise a speaker, at least one processor, and at least one memory. The memory can comprise program instructions configured to be executed by the at least one processor such that the program instructions are configured to cause the speaker to emit a first audio command in response to the maintenance system determining that the particle size is smaller than a predetermined threshold. The program instructions can be configured to cause the speaker to emit a second audio command in response to the maintenance system determining that the particle size is larger than the predetermined threshold. The second audio command can be configured to communicate different information than the first audio command to a first rider inside the vehicle. 
     In some embodiments, the vehicle is configured to drive a first rider to a destination, and the maintenance system comprises at least one processor and at least one memory. The memory can comprise program instructions configured to be executed by the at least one processor. 
     In some embodiments, program instructions comprise a first mode and a second mode. In the first mode, the maintenance system can make the vehicle available to accept a pick-up request of a second rider. In the second mode, the maintenance system can make the vehicle unavailable to accept the pick-up request. The maintenance system can be configured to enter the second mode in response to the smoke detection system detecting the smoke inside the vehicle. The maintenance system can be configured to exit the second mode and enter the first mode in response to the smoke detection system no longer detecting the smoke inside the vehicle, the maintenance system detecting that a concentration of the smoke is less than a predetermined threshold, the maintenance system receiving a communication in response to the vehicle having been cleaned, and/or the maintenance system receiving an indication (such as GPS data) indicative of the vehicle having left a cleaning facility. 
     In some embodiments, a maintenance system is configured to be used with a self-driving vehicle. A maintenance system can comprise a smoke detection system coupled to the vehicle and configured to detect smoke inside a cabin of the vehicle. The smoke detection system can be coupled to the vehicle by being placed inside the vehicle, being attached to a roof of an interior of the vehicle, and/or coupled to the vehicle in any suitable way configured to enable the smoke detection system to detect smoke inside the vehicle. A maintenance system can comprise a vehicle management system configured to autonomously drive the vehicle. 
     In some embodiments, a vehicle management system is configured to respond in response to the smoke detection system detecting the smoke inside the vehicle. Embodiments described herein include many different ways in which the vehicle management system can respond to the smoke detection system detecting smoke inside the vehicle. Responses can protect the safety of riders inside the vehicle and/or can reduce smoke damage to the vehicle. 
     In some embodiments, a maintenance system comprises a communication system configured to send a first wireless communication to a remote computing device in response to the smoke detection system detecting the smoke inside the vehicle. The remote computing device can be associated with a manager of the vehicle such that the first wireless communication is configured to notify the manager regarding the smoke inside the vehicle. 
     In some embodiments, the vehicle management system comprises a motor configured to roll down a window of the vehicle, and the vehicle management system is configured to use the motor to automatically roll down the window in response to the smoke detection system detecting the smoke inside the vehicle. 
     In some embodiments, the vehicle management system comprises a motor configured to roll down a window of the vehicle. The vehicle management system can comprise a rain sensor configured to detect an indication of rain on the vehicle. The vehicle management system can be configured to use the motor to automatically roll down the window in response to the smoke detection system detecting the smoke inside the vehicle and in response to the rain sensor not detecting the indication of the rain. 
     In some embodiments, the vehicle management system comprises a motor configured to roll down a window of the vehicle. The smoke detection system can be configured to analyze a particle size of the smoke to determine if the particle size is smaller than a predetermined threshold. The vehicle management system can be configured to use the motor to automatically roll down the window in response to the smoke detection system detecting the smoke inside the vehicle and determining that the particle size is less than the predetermined threshold. 
     In some embodiments, the vehicle management system comprises a temperature management system. The temperature management system can comprise a thermometer, an air conditioner, a heater, and a ventilation system. The ventilation system can comprise a fan configured to circulate air in the cabin of the vehicle. The vehicle management system can be configured to increase and/or decrease an ambient temperature inside the cabin by at least ten degrees Fahrenheit in response to the smoke detection system detecting the smoke inside the vehicle. In response to the smoke detection system detecting the smoke inside the vehicle, the vehicle management system can increase and/or decrease the ambient temperature to decrease a comfort level of a first rider. 
     In some embodiments, the maintenance system comprises at least one processor and at least one memory having program instructions configured to be executed by the at least one processor. The program instructions can be configured to cause the vehicle management system to at least one of increase and decrease the ambient temperature by at least ten degrees Fahrenheit and by less than thirty degrees Fahrenheit. In response to the smoke detection system detecting smoke inside the vehicle, the program instructions can cause the vehicle management system to increase and/or decrease the ambient temperature (e.g., by at least ten degrees Fahrenheit and/or by less than thirty degrees Fahrenheit) to decrease the comfort level of a rider inside the vehicle. 
     In some embodiments, the vehicle management system comprises a speaker and/or a display screen. At least one of the speaker and the display screen can be configured to provide at least one of audio instructions and visual instructions to the first rider. At least one of the audio instructions and the visual instructions can be configured to instruct the first rider to cease smoking in order to enable changing the ambient temperature to increase the comfort level. 
     In some embodiments, the smoke detection system is configured to analyze a particle size of the smoke to determine if the particle size is smaller than a predetermined threshold. The vehicle management system can be configured to increase and/or decrease the ambient temperature inside the cabin (to decrease the comfort level of the first rider) in response to the maintenance system detecting the smoke inside the vehicle and determining that the particle size is smaller than the predetermined threshold. 
     In some embodiments, the vehicle management system is configured to automatically at least partially restore (e.g., increase) the comfort level in response to the smoke detection system no longer detecting the smoke inside the vehicle, detecting that a concentration of the smoke is less than a predetermined threshold, detecting that a concentration of the smoke is decreasing, and/or detecting that a concentration of the smoke has decreased by at least a predetermined amount and/or ratio. 
     In some embodiments, the vehicle management system comprises a lighting system configured to illuminate at least a portion of an interior of the vehicle. The lighting system can comprise at least one light coupled to an interior of the vehicle. The lighting system can be configured to illuminate at least one of a seat of the vehicle and a majority of the cabin (of the vehicle). The vehicle management system can be configured to use the lighting system to illuminate at least one of the seat and the majority of the cabin in response to the smoke detection system detecting the smoke inside the vehicle. 
     In some embodiments, the maintenance system comprises at least one processor and at least one memory having program instructions that when executed by the at least one processor are configured to cause the vehicle management system to illuminate at least one of the seat and the majority of the cabin in response to the smoke detection system detecting the smoke inside the vehicle. 
     In some embodiments, the vehicle management system is configured to cease illuminating at least one of the seat and the majority of the cabin in response to the smoke detection system in response to the smoke detection system no longer detecting smoke inside the vehicle, detecting that a concentration of the smoke is less than a predetermined threshold, detecting that a concentration of the smoke is decreasing, and/or detecting that a concentration of the smoke has decreased by at least a predetermined amount and/or ratio. 
     In some embodiments, the smoke detection system is configured to analyze a particle size of the smoke to determine if the particle size is smaller than a predetermined threshold. The vehicle management system can be configured to illuminate at least one of the seat of the vehicle and the majority of the cabin in response to the maintenance system detecting the smoke inside the vehicle and determining that the particle size is smaller than the predetermined threshold. 
     In some embodiments, the vehicle management system comprises at least one of a speaker and a display screen. At least one of the speaker and the display screen can be configured to provide at least one of audio instructions and visual instructions to a first rider inside the vehicle. At least one of the audio instructions and the visual instructions can be configured to instruct the first rider to cease smoking while at least one of the seat and the majority are illuminated by the lighting system. 
     In some embodiments, the smoke detection system (that is coupled to the vehicle) comprises an ionization smoke detector configured to detect cigarette smoking and comprises an optical smoke detector configured to detect electronic cigarette aerosol by analyzing a particle size of the aerosol and determining that the particle size is indicative of electronic cigarette use. 
     In some embodiments, the maintenance system comprises a communication system configured to send a first wireless communication to a remote computing device in response to the smoke detection system detecting the smoke. The smoke detection system (coupled to the vehicle) can be configured to analyze a particle size of the smoke. The communication system can be configured to send the first wireless communication identifying the smoke as an aerosol in response to the smoke detection system determining that the particle size is greater than a predetermined threshold. The communication system can be configured to send the first wireless communication identifying the smoke as cigarette smoking in response to the smoke detection system determining that the particle size is less than the predetermined threshold. The smoke detection system can comprise an optical smoke detector configured to analyze the particle size. 
     The disclosure also includes a safety system comprising a self-driving vehicle, a vehicle management system configured to autonomously drive the self-driving vehicle, and a smoke detection system coupled to the self-driving vehicle and configured to detect smoke inside a cabin of the self-driving vehicle. 
     In many embodiments, the self-driving vehicle comprises a door and a door lock configured to impede opening the door. In some embodiments, the safety system comprises at least one processor and at least one memory having program instructions that when executed by the at least one processor are configured to cause the vehicle management system to unlock the door of the self-driving vehicle in response to the smoke detection system detecting the smoke inside the self-driving vehicle. 
     In some embodiments, the safety system includes a speed detection system, wherein the program instructions are configured to cause the vehicle management system to automatically unlock the door in response to the smoke detection system detecting the smoke inside the self-driving vehicle and the speed detection system determining that the self-driving vehicle is moving at a first speed that is less than a first speed threshold. In some embodiments, the first speed threshold is less than 30 miles per hour. 
     In some embodiments, the safety system includes a speed detection system, wherein the program instructions are configured to cause the vehicle management system to unlock the door in response to the smoke detection system detecting the smoke inside the self-driving vehicle and the speed detection system determining that the self-driving vehicle is moving at a first speed that is less than a first speed threshold, wherein the first speed threshold is less than 30 miles per hour. Furthermore, the program instructions may be configured to cause the motor to at least partially open the door in response to the smoke detection system detecting the smoke inside the self-driving vehicle and the speed detection system determining that the self-driving vehicle is moving at a second speed that is less than a second speed threshold, wherein the second speed threshold is less than 15 miles per hour. 
     Additionally, in some embodiments, the self-driving vehicle comprises a motor configured to at least partially open the door, wherein the program instructions are configured to cause the motor to at least partially open the door in response to the smoke detection system detecting the smoke inside the self-driving vehicle. 
     The self-driving vehicle comprises a window and a motor configured to at least partially open the window, wherein the program instructions are configured to cause the motor to at least partially open the window in response to the smoke detection system detecting the smoke inside the self-driving vehicle. 
     In some embodiments, the smoke detection system is configured to detect a concentration of the smoke, and the program instructions are configured to cause the vehicle management system to automatically unlock the door of the self-driving vehicle in response to the smoke detection system detecting the smoke inside the self-driving vehicle and the safety system determining the concentration of the smoke is greater than a predetermined threshold. 
     Furthermore, in some embodiments, the smoke detection system is configured to detect a particle size of the smoke, and the vehicle management system is configured to unlock the door in response to the smoke detection system detecting the smoke inside the self-driving vehicle and the safety system determining the particle size is smaller than a predetermined threshold. 
     In some embodiments, the self-driving vehicle comprises a window and a motor configured to at least partially open the window. Accordingly, in some embodiments, the smoke detection system is configured to detect a particle size of the smoke, the program instructions are configured to cause the vehicle management system to unlock the door in response to the safety system determining the particle size is smaller than a first predetermined threshold. In some embodiments, the program instructions are configured to cause the motor to at least partially open the window in response to the safety system determining the particle size is larger than a second predetermined threshold. 
     Even still, in some embodiments, the self-driving vehicle comprises an actuator configured to move the door lock to an unlocked state. Accordingly, in some embodiments, the smoke detection system comprises a camera and at least one of an ionization smoke detector and an optical smoke detector, wherein the camera is configured to take a picture showing at least a portion of the cabin. In some embodiments, the program instructions are configured to cause the motor to at least partially open the window in response to the safety system determining that the picture shows the smoke, and the program instructions are configured to cause the actuator to move the door lock to the unlocked state in response to at least one of the ionization smoke detector and the optical smoke detector detecting the smoke inside the self-driving vehicle. 
     In some embodiments, the program instructions are configured to automatically unlock the door lock in response to the smoke detection system detecting the smoke inside the self-driving vehicle and the safety system receiving a verification input from a rider. The verification input is configured to confirm a presence of the smoke in the self-driving vehicle. 
     Additionally, in some embodiments, the self-driving vehicle comprises a display screen. Accordingly, in some embodiments, the program instructions are configured to receive the verification input from the rider via at least one of the display screen and a button pressed by the rider in response to a visual request shown on the display screen. In response to the smoke detection system detecting the smoke, the program instructions may be configured to cause the display screen to emit the visual request for the rider to confirm the presence of the smoke. 
     Furthermore, in some embodiments, the self-driving vehicle comprises a microphone and a speaker. In some embodiments, the verification input comprises a verbal response received from the rider via the microphone in response to the program instructions causing the speaker to emit an audio request for the rider to confirm the presence of the smoke, and in response to the smoke detection system detecting the smoke, the program instructions are configured to cause the speaker to emit the audio request. 
     In some embodiments, the self-driving vehicle comprises a camera, and the verification input comprises a gesture made by the rider and recorded by the camera. Additionally, in some embodiments, the verification input comprises a wireless communication transmitted from a remote computing device of the rider to the safety system. 
     In some embodiments, the self-driving vehicle comprises a speaker, and in response to the smoke detection system detecting the smoke inside the self-driving vehicle, the program instructions are configured to cause the speaker to emit audio instructions, wherein the audio instructions are configured to alert a rider regarding at least one of the smoke and the door being unlocked. 
     In some embodiments, the self-driving vehicle comprises a display screen, and in response to the smoke detection system detecting the smoke inside the self-driving vehicle, the program instructions are configured to cause the display screen to show visual instructions to a rider, wherein the visual instructions are configured to alert the rider regarding at least one of the smoke and the door being unlocked. 
     Even still, in some embodiments, the safety system includes a temperature detection system coupled to the self-driving vehicle and configured to detect a temperature inside at least a portion of self-driving vehicle. The program instructions may thereby be configured to cause the vehicle management system to unlock the door in response to the smoke detection system detecting the smoke inside the self-driving vehicle and the temperature detection system detecting the temperature greater than a predetermined temperature threshold. In some embodiments, the temperature detection system comprises a camera system configured to identify the smoke. Furthermore, in some embodiments, the temperature is located within 24 inches of the smoke. In other words, in some embodiments, the temperature detection system is configured to detect a temperature within 24 inches of the smoke, within 12 inches of the smoke, and even within 1 inch of the smoke. 
     Furthermore, in some embodiments, the door comprises an unlocked state and a locked state, and the program instructions are configured to verify the door is in the unlocked state in response to the smoke detection system detecting the smoke inside the self-driving vehicle. 
     The disclosure also includes a safety system comprising a self-driving vehicle configured to transport a rider, a vehicle management system configured to autonomously drive the self-driving vehicle, a seat coupled to the self-driving vehicle, and a seat belt configured to alternatively have a buckled state and an unbuckled state. In some embodiments, when the seat belt is in the buckled state the seat belt is configured to secure the rider in the seat and in the unbuckled state the seat belt is configured to enable the rider to exit the seat. In many embodiments, the safety system further includes a smoke detection system coupled to the self-driving vehicle and configured to detect smoke inside a cabin of the self-driving vehicle. 
     In some embodiments, the safety system further includes at least one processor and at least one memory having program instructions that when executed by the at least one processor are configured to cause the vehicle management system to switch the seat belt from the buckled state to the unbuckled state in response to the smoke detection system detecting the smoke inside the self-driving vehicle. 
     Additionally, in some embodiments, the safety system includes a first actuator configured to switch the seat belt from the buckled state to the unbuckled state, wherein the program instructions are configured to send a control signal to the first actuator in response to the smoke detection system detecting the smoke inside the self-driving vehicle, wherein the control signal is configured to cause the first actuator to switch the seat belt from the buckled state to the unbuckled state. 
     Even still, in some embodiments, the safety system further includes a seat belt sensor configured to detect the buckled state of the seat belt, wherein the program instructions are configured to cause the vehicle management system to switch the seat belt from the buckled state to the unbuckled state in response to the smoke detection system detecting the smoke inside the self-driving vehicle and the seat belt sensor detecting the buckled state. 
     The safety system may also include an occupancy sensor configured to detect the rider sitting in the seat, wherein the program instructions are configured to cause the vehicle management system to switch the seat belt from the buckled state to the unbuckled state in response to the smoke detection system detecting the smoke inside the self-driving vehicle and the occupancy sensor detecting the rider sitting in the seat. 
     In some embodiments, the safety system further includes a seat belt sensor configured to detect the buckled state of the seat belt, wherein the program instructions are configured to cause the vehicle management system to switch the seat belt from the buckled state to the unbuckled state in response to the smoke detection system detecting the smoke inside the self-driving vehicle, the occupancy sensor detecting the rider sitting in the seat, and the seat belt sensor detecting the buckled state. 
     Furthermore, in some embodiments, the safety system includes a speed detection system, wherein the program instructions are configured to cause the vehicle management system to automatically switch the seat belt from the buckled state to the unbuckled state in response to the smoke detection system detecting the smoke inside the self-driving vehicle and the speed detection system determining that the self-driving vehicle is moving at a first speed that is less than a first speed threshold. In some embodiments, the first speed threshold is less than 30 miles per hour. In some embodiments, the first speed threshold is greater than one mile per hour. 
     In some embodiments, the self-driving vehicle comprises a door, a door lock configured to impede opening the door, and a door lock actuator configured to arrange the door lock to an unlocked state. Accordingly, in some embodiments, the program instructions are configured to cause the door lock actuator to unlock the door in response to the smoke detection system detecting the smoke inside the self-driving vehicle. 
     Accordingly, in some embodiments, wherein the self-driving vehicle comprises a door actuator configured to at least partially open the door, the program instructions are configured to cause the door actuator to at least partially open the door in response to the smoke detection system detecting the smoke inside the self-driving vehicle. 
     Additionally, in some embodiments, wherein the self-driving vehicle comprises a door actuator configured to at least partially open the door, the program instructions are configured to cause the door actuator to at least partially open the door in response to the smoke detection system detecting the smoke inside the self-driving vehicle. In some embodiments, the safety system further comprises a speed detection system, and the program instructions are configured to cause the vehicle management system to switch the seat belt from the buckled state to the unbuckled state in response to the smoke detection system detecting the smoke inside the self-driving vehicle and the speed detection system determining that the self-driving vehicle is moving at a first speed that is less than a first speed threshold, wherein the first speed threshold is less than 30 miles per hour. In some embodiments, the program instructions are configured to cause the door actuator to at least partially open the door in response to the smoke detection system detecting the smoke inside the self-driving vehicle and the speed detection system determining that the self-driving vehicle is moving at a second speed that is less than a second speed threshold, wherein the second speed threshold is less than 15 miles per hour. In some embodiments, the first speed threshold is greater than 1 mile per hour and is greater than the second speed threshold. 
     In some embodiments, wherein the self-driving vehicle comprises a window and a motor configured to at least partially open the window, wherein in response to the smoke detection system detecting the smoke inside the self-driving vehicle the program instructions are configured to cause the motor to at least partially open the window prior to the seat belt switching from the buckled state to the unbuckled state. 
     In some embodiments, the smoke detection system is configured to detect a concentration of the smoke, and the program instructions are configured to cause the vehicle management system to automatically switch the seat belt from the buckled state to the unbuckled state in response to the smoke detection system detecting the smoke inside the self-driving vehicle and the safety system determining the concentration of the smoke is greater than a predetermined threshold. 
     Additionally, in some embodiments, the smoke detection system is configured to detect a particle size of the smoke, and the vehicle management system is configured to switch the seat belt from the buckled state to the unbuckled state in response to the smoke detection system detecting the smoke inside the self-driving vehicle and the safety system determining the particle size is smaller than a predetermined threshold. 
     In some embodiments, wherein the self-driving vehicle comprises a window and a motor configured to at least partially open the window, the smoke detection system is configured to detect a particle size of the smoke, the program instructions are configured to cause the vehicle management system to switch the seat belt from the buckled state to the unbuckled state in response to the safety system determining the particle size is smaller than a first predetermined threshold, and the program instructions are configured to cause the motor to at least partially open the window in response to the safety system determining the particle size is larger than a second predetermined threshold. 
     Furthermore, in some embodiments, wherein the self-driving vehicle comprises a window and a motor configured to at least partially open the window, the smoke detection system comprises a camera and at least one of an ionization smoke detector and an optical smoke detector, wherein the camera is configured to take a picture showing at least a portion of the cabin. Accordingly, in some embodiments, the program instructions are configured to cause the motor to at least partially open the window in response to the safety system determining that the picture shows the smoke, and the program instructions are configured to cause the vehicle management system to switch the seat belt from the buckled state to the unbuckled state in response to at least one of the ionization smoke detector and the optical smoke detector detecting the smoke inside the self-driving vehicle. 
     In some embodiments, the safety system further includes a temperature detection system coupled to the self-driving vehicle and configured to detect a temperature inside at least a portion of the self-driving vehicle, wherein the program instructions are configured to cause the vehicle management system to switch the seat belt from the buckled state to the unbuckled state in response to the smoke detection system detecting the smoke inside the self-driving vehicle and the temperature detection system detecting that the temperature is greater than a predetermined temperature threshold. In some embodiments, the temperature detection system comprises a thermal imaging camera. 
     In some embodiments, the safety system further includes an object detection system configured to detect a second vehicle and having at least one of a camera, a radar, and a lidar, wherein at least one of the camera, the radar, and the lidar is coupled to the self-driving vehicle to enable the objection detection system to detect the second vehicle, and the program instructions are configured to cause the vehicle management system to switch the seat belt from the buckled state to the unbuckled state in response to the smoke detection system detecting the smoke inside the self-driving vehicle and in response to at least one of: the object detection system detecting that the second vehicle is at least a predetermined distance from the self-driving vehicle, the object detection system detecting that the second vehicle is not on a collision course with the self-driving vehicle, and the vehicle management system determining, based on data from the object detection system, that the second vehicle has less than a predetermined risk threshold of colliding with the self-driving vehicle. 
     In some embodiments, a maintenance system is configured to be used with a self-driving vehicle. In some embodiments, a maintenance system comprises a smoke detection system coupled to the vehicle and configured to detect smoke inside a cabin of the vehicle; and a vehicle management system configured to autonomously drive the vehicle. 
     In some embodiments, the smoke detection system coupled to the vehicle comprises an ionization smoke detector configured to detect cigarette smoke and comprises an optical smoke detector configured to detect electronic cigarette aerosol by analyzing a particle size of the aerosol and determining that the particle size is indicative of electronic cigarette use. 
     In some embodiments, the smoke detection system comprises an ionization smoke detector configured to detect cigarette smoke and comprises an optical smoke detector configured to detect electronic cigarette aerosol by detecting that a particle size of the aerosol is greater than a predetermined threshold. 
     In some embodiments, the maintenance system comprises program instructions configured to detect the cigarette smoke based on first data from the ionization smoke detector. Program instructions can be configured to detect the electronic cigarette aerosol based on second data from the optical smoke detector. Program instructions can be configured to detect the electronic cigarette aerosol by analyzing the particle size of the aerosol and determining that the particle size is greater than the predetermined threshold. 
     In some embodiments, the maintenance system comprises a communication system and program instructions. Program instructions can be configured to cause the communication system to send a first wireless communication to a remote computing device in response to the smoke detection system detecting the smoke inside the vehicle. 
     In some embodiments, a smoke detection system is configured to analyze a particle size of the smoke. Program instructions can be configured to cause the communication system to send the first wireless communication identifying the smoke as an aerosol in response to the smoke detection system determining that the particle size is greater than a first predetermined threshold. Program instructions can be configured to cause the communication system to send the first wireless communication identifying the smoke as cigarette smoke in response to the smoke detection system determining that the particle size is less than a second predetermined threshold that is smaller than or equal to the first predetermined threshold. 
     In some embodiments, a smoke detection system comprises at least one optical smoke detector configured to analyze the particle size of the smoke. 
     In some embodiments, a communication system is configured to send a first wireless communication to a remote computing device in response to the smoke detection system detecting the smoke. The smoke detection system can be coupled to the vehicle and can be configured to analyze a particle size of the smoke. The communication system can be configured to send the first wireless communication identifying the smoke as an aerosol in response to the smoke detection system determining that the particle size is greater than a predetermined threshold. The communication system can be configured to send the first wireless communication identifying the smoke as cigarette smoke in response to the smoke detection system determining that the particle size is less than the predetermined threshold. The smoke detection system can comprise an optical smoke detector configured to analyze the particle size. The smoke detection system can comprise an ionization smoke detector configured to detect the cigarette smoke. 
     In some embodiments, a safety system comprises a self-driving vehicle; a temperature detection system coupled to the self-driving vehicle and configured to detect a first temperature of a first portion of the self-driving vehicle; and a vehicle management system configured to autonomously drive the self-driving vehicle. 
     In some embodiments, the vehicle management system comprises program instructions configured to intentionally increase a travel time of the self-driving vehicle in response to the temperature detection system detecting that the first temperature exceeds a predetermined threshold. 
     In some embodiments, at least one of a passenger cabin of the self-driving vehicle (which is configured to hold human passengers), a motor compartment of the self-driving vehicle (which can comprise one or more motors), a battery compartment of the self-driving vehicle (which can comprise one or more batteries), and a cargo compartment of the self-driving vehicle (which can be configured to hold cargo that is transported by the self-driving vehicle) comprises the first portion. 
     In some embodiments, a temperature detection system can comprise at least one of an infrared camera, a thermocouple, a resistance temperature detector, a thermistor, a pyrometer, and a thermometer. At least one of the infrared camera, the thermocouple, the resistance temperature detector, the thermistor, the pyrometer, and the thermometer can be configured to detect the first temperature of the first portion. 
     In some embodiments, the vehicle management system is configured to increase the travel time by changing from a first travel route to a destination chosen by a first rider to a second travel route. The vehicle management system can be configured to change from the first travel route to the second travel route to intentionally increase the travel time in response to the temperature detection system detecting that the first temperature exceeds the predetermined threshold. 
     In some embodiments, a safety system comprises at least one processor and at least one memory having the program instructions that when executed by the at least one processor are configured to cause the vehicle management system to increase the travel time of the self-driving vehicle in response to the temperature detection system detecting that the first temperature exceeds the predetermined threshold. 
     In some embodiments, a vehicle management system is configured to reduce a speed of the self-driving vehicle in response to the temperature detection system detecting that at least one of the first temperature exceeds a predetermined temperature threshold and a trajectory of the first temperature exceeds a predetermined trajectory threshold. 
     In some embodiments, a safety system comprises at least one processor and at least one memory having program instructions that when executed by the at least one processor are configured to cause the vehicle management system to intentionally reduce the speed of the self-driving vehicle to a velocity below a local speed limit and above five miles per hour in response to the temperature detection system detecting that the first temperature exceeds the predetermined temperature threshold. 
     In some embodiments, a safety system comprises at least one processor and at least one memory having program instructions that when executed by the at least one processor are configured to cause the vehicle management system to intentionally reduce the speed of the self-driving vehicle in response to the temperature detection system detecting that the trajectory of the first temperature exceeds the predetermined trajectory threshold. 
     In some embodiments, a temperature detection system comprises at least one of an infrared camera, a thermocouple, a resistance temperature detector, a thermistor, a pyrometer, and a thermometer. At least one of the infrared camera, the thermocouple, the resistance temperature detector, the thermistor, the pyrometer, and the thermometer can be configured to detect the first temperature of the first portion. 
     In some embodiments, at least one of a passenger cabin of the self-driving vehicle, a motor compartment of the self-driving vehicle, a battery compartment of the self-driving vehicle, and a cargo compartment of the self-driving vehicle comprises the first portion of the self-driving vehicle. The battery compartment can comprise one or more batteries. A battery can be housed in a battery housing. The motor compartment can comprise one or more motors configured to propel the self-driving vehicle. Compartments can be complete or partial enclosures. 
     The temperature detection system can comprise at least one of an infrared camera, a thermocouple, a resistance temperature detector, a thermistor, a pyrometer, and a thermometer. At least one of the infrared camera, the thermocouple, the resistance temperature detector, the thermistor, the pyrometer, and the thermometer can be configured to detect the first temperature of the first portion. 
     In some embodiments, a self-driving vehicle comprises a passenger cabin comprising the first portion. The temperature detection system can comprise an infrared camera coupled to a second portion of the self-driving vehicle such that the infrared camera is configured to detect the first temperature of the first portion of the passenger cabin. The vehicle management system can comprise program instructions configured to reduce the speed in response to the temperature detection system detecting that the first temperature exceeds the predetermined temperature threshold. 
     In some embodiments, a self-driving vehicle comprises a motor compartment and a battery compartment. At least one of the motor compartment and the battery compartment can comprise the first portion of the self-driving vehicle. The temperature detection system can comprise an infrared camera coupled to a second portion of the self-driving vehicle such that the infrared camera is configured to detect the first temperature of the first portion. The vehicle management system can comprise program instructions configured to reduce the speed in response to the temperature detection system detecting that the first temperature exceeds the predetermined temperature threshold. 
     In some embodiments, a motor compartment comprises an electric motor and/or a combustion motor. Combustion motors can use many different types of fuel including gasoline and diesel. Combustion motors can be gasoline engines. Combustion motors can be diesel engines. A self-driving vehicle can comprise a motor compartment, which can comprise the first portion of the self-driving vehicle. 
     In some embodiments, the temperature detection system comprises at least one of a thermocouple, a resistance temperature detector, a thermistor, a pyrometer, and a thermometer. At least one of the thermocouple, the resistance temperature detector, the thermistor, the pyrometer, and the thermometer can be configured to detect the first temperature of the first portion of the motor compartment. The vehicle management system can comprise program instructions configured to reduce the speed in response to at least one of the thermocouple, the resistance temperature detector, the thermistor, the pyrometer, and the thermometer detecting that at least one of the first temperature exceeds the predetermined temperature threshold and the trajectory of the first temperature exceeds the predetermined trajectory threshold. 
     In some embodiments, a self-driving vehicle comprises a battery compartment comprising the first portion of the self-driving vehicle. The temperature detection system can comprise at least one of an infrared camera, a thermocouple, a resistance temperature detector, a thermistor, a pyrometer, and a thermometer. At least one of the infrared camera, the thermocouple, the resistance temperature detector, the thermistor, the pyrometer, and the thermometer can be configured to detect the first temperature of the first portion of the battery compartment. The vehicle management system can comprise program instructions configured to reduce the speed of the self-driving vehicle in response to at least one of the infrared camera, the thermocouple, the resistance temperature detector, the thermistor, the pyrometer, and the thermometer detecting that at least one of the first temperature exceeds the predetermined temperature threshold and the trajectory of the first temperature exceeds the predetermined trajectory threshold. 
     In some embodiments, a self-driving vehicle comprises a battery and a battery housing configured to house the battery. At least one of the battery and the battery housing can comprise the first portion of the self-driving vehicle. The temperature detection system can comprise at least one of a thermocouple, a resistance temperature detector, a thermistor, and a thermometer. At least one of the thermocouple, the resistance temperature detector, the thermistor, and the thermometer can be coupled to at least one of the battery and the battery housing. At least one of the thermocouple, the resistance temperature detector, the thermistor, and the thermometer can be configured to detect the first temperature of the first portion. 
     In some embodiments, a vehicle management system comprises program instructions configured to intentionally reduce the speed of the self-driving vehicle in response to at least one of the thermocouple, the resistance temperature detector, the thermistor, and the thermometer detecting that at least one of the first temperature exceeds the predetermined temperature threshold and the trajectory of the first temperature exceeds the predetermined trajectory threshold. 
     In some embodiments, a self-driving vehicle is configured to drive a first rider to a destination chosen by the first rider. A vehicle management system can comprise at least one processor and at least one memory. The at least one memory can comprise program instructions. The at least one memory can comprise at least one of a temperature threshold and a trajectory threshold. The program instructions can be configured to cause the self-driving vehicle to cease driving toward the destination in response to the temperature detection system detecting that at least one of the first temperature exceeds the temperature threshold and a trajectory of the first temperature exceeds the trajectory threshold. 
     In some embodiments, a temperature detection system comprises at least one of an infrared camera, a thermocouple, a resistance temperature detector, a thermistor, a pyrometer, and a thermometer. At least one of the infrared camera, the thermocouple, the resistance temperature detector, the thermistor, the pyrometer, and the thermometer can be configured to detect the first temperature of the first portion. 
     In some embodiments, program instructions are configured to cause the self-driving vehicle to intentionally cease driving toward the destination in response to the temperature detection system detecting that the trajectory of the first temperature exceeds the trajectory threshold. 
     In some embodiments, a self-driving vehicle comprises a door and a door lock configured to impede opening the door. Program instructions can be configured to cause the vehicle management system to unlock the door of the self-driving vehicle in response to the temperature detection system detecting that at least one of the first temperature exceeds the temperature threshold and the trajectory of the first temperature exceeds the trajectory threshold. 
     In some embodiments, a safety system comprises a speed detection system. Program instructions can be configured to cause the vehicle management system to automatically unlock the door in response to the temperature detection system detecting that the first temperature exceeds the temperature threshold and the speed detection system determining that the self-driving vehicle has a movement speed that is less than a first speed threshold. In some embodiments, a first speed threshold can be less than fifteen miles per hour, less than five miles per hour, and/or greater than 0.2 miles per hour. 
     In some embodiments, a self-driving vehicle comprises a door and a motor configured to open the door. Program instructions can be configured to cause the motor to open the door in response to the temperature detection system detecting that the first temperature exceeds the temperature threshold and the safety system detecting that the self-driving vehicle has a movement speed that is less than a first speed threshold. In some embodiments, a first speed threshold is less than ten miles per hour, less than two miles per hour, and/or greater than 0.2 miles per hour. 
     In some embodiments, a safety system comprises a self-driving vehicle. The safety system can comprise a temperature detection system coupled to the self-driving vehicle and configured to detect a first temperature of a first portion of the self-driving vehicle. The safety system can comprise a vehicle management system comprising program instructions having a first mode and a second mode. The vehicle management system can be configured to autonomously drive the self-driving vehicle. 
     In some embodiments, a vehicle management system comprises at least one memory comprising at least one of a temperature threshold and a trajectory threshold. 
     In some embodiments, in the first mode, the safety system is configured to make the self-driving vehicle available to accept a pick-up request of a rider. 
     In some embodiments, in the second mode, the safety system is configured to make the self-driving vehicle unavailable to accept the pick-up request. 
     In some embodiments, program instructions are configured to exit the first mode and enter the second mode in response to the temperature detection system detecting that at least one of the first temperature exceeds the temperature threshold and a trajectory of the first temperature exceeds the trajectory threshold. 
     In some embodiments, a temperature detection system comprises at least one of an infrared camera, a thermocouple, a resistance temperature detector, a thermistor, a pyrometer, and a thermometer, and at least one of the infrared camera, the thermocouple, the resistance temperature detector, the thermistor, the pyrometer, and the thermometer is configured to detect the first temperature of the first portion. 
     In some embodiments, program instructions are configured to exit the first mode and enter the second mode in response to the temperature detection system detecting that the trajectory of the first temperature exceeds the trajectory threshold. 
     In some embodiments, the safety system is configured to exit the second mode and enter the first mode in response to the temperature detection system detecting that the first temperature does not exceed the temperature threshold. 
     In some embodiments, the safety system is configured to exit the second mode and enter the first mode in response to the temperature detection system detecting that the trajectory of the first temperature does not exceed the trajectory threshold. 
     In some embodiments, a self-driving vehicle comprises a passenger cabin comprising the first portion. A temperature detection system can comprise an infrared camera coupled to a second portion of the self-driving vehicle such that the infrared camera is configured to detect the first temperature of the first portion of the passenger cabin. Program instructions can be configured to exit the first mode and enter the second mode in response to the infrared camera detecting that the first temperature of the first portion of the passenger cabin exceeds the temperature threshold. 
     In some embodiments, a motor compartment comprises an electric motor and/or a combustion motor. Combustion motors can use many different types of fuel including gasoline and diesel. In some embodiments, the combustion motor can be a Ford Raptor engine or a Toyota Tundra engine. In some embodiments, the motor can be a Toyota Prius hybrid motor system. In some embodiments, the motor can be a Tesla electric motor system. 
     In some embodiments, a self-driving vehicle comprises a motor compartment comprising the first portion of the self-driving vehicle. A temperature detection system can comprise at least one of an infrared camera, a thermocouple, a resistance temperature detector, a thermistor, a pyrometer, and a thermometer. At least one of the infrared camera, the thermocouple, the resistance temperature detector, the thermistor, the pyrometer, and the thermometer can be configured to detect the first temperature of the first portion of the motor compartment. 
     In some embodiments, program instructions are configured to exit the first mode and enter the second mode in response to at least one of the infrared camera, the thermocouple, the resistance temperature detector, the thermistor, the pyrometer, and the thermometer detecting that the first temperature of the first portion of the motor compartment exceeds the temperature threshold. 
     In some embodiments, a self-driving vehicle comprises a battery compartment comprising the first portion of the self-driving vehicle. A temperature detection system can comprise at least one of an infrared camera, a thermocouple, a resistance temperature detector, a thermistor, a pyrometer, and a thermometer. At least one of the infrared camera, the thermocouple, the resistance temperature detector, the thermistor, the pyrometer, and the thermometer can be configured to detect the first temperature of the first portion of the battery compartment. 
     In some embodiments, program instructions are configured to exit the first mode and enter the second mode in response to at least one of the infrared camera, the thermocouple, the resistance temperature detector, the thermistor, the pyrometer, and the thermometer detecting that at least one of the first temperature exceeds the temperature threshold and the trajectory of the first temperature exceeds the trajectory threshold. 
     In some embodiments, a safety system comprises a self-driving vehicle. The safety system can comprise a temperature detection system coupled to the self-driving vehicle and configured to detect a first temperature of a first portion of the self-driving vehicle. The safety system can comprise a vehicle management system configured to autonomously drive the self-driving vehicle and comprising program instructions having a first mode and a second mode. 
     In some embodiments, a vehicle management system comprises at least one memory comprising at least one of a temperature threshold and a trajectory threshold. Program instructions can be configured to cause the self-driving vehicle to stop moving via the first mode in response to the temperature detection system detecting that at least one of the first temperature exceeds the temperature threshold and a trajectory of the first temperature exceeds the trajectory threshold. Program instructions can be configured to cause the self-driving vehicle to stop moving via the second mode in response to the safety system detecting an indication of a person located inside the self-driving vehicle and the temperature detection system detecting that at least one of the first temperature exceeds the temperature threshold and the trajectory of the first temperature exceeds the trajectory threshold. 
     In some embodiments, the second mode can be configured to enable the self-driving vehicle to stop more quickly than the first mode. The second mode can be configured to enable the self-driving vehicle to move at a greater speed than the first mode. The vehicle management system can be configured to determine a local speed limit, and the second mode can be configured to enable the self-driving vehicle to exceed the local speed limit by a greater amount than the first mode. The second mode can be configured to enable the self-driving vehicle to accelerate faster than the first mode (e.g., to reach a stopping location faster than would be possible in the first mode). The second mode can be configured to enable the self-driving vehicle to decelerate faster than the first mode (e.g., to enable the self-driving vehicle to stop more quickly than would be possible in the first mode). 
     In some embodiments, a self-driving vehicle is configured to drive on a road. The vehicle management system can comprise a vehicle guidance system having at least one of a camera, a radar, and a lidar. The vehicle guidance system can be configured to detect objects (e.g., other cars) located outside the self-driving vehicle on the road. Program instructions can be configured to enable the self-driving vehicle to come closer to the objects (e.g., other cars) in the second mode than in the first mode (e.g., to enable the self-driving vehicle to reach a stopping location faster than would be possible in the first mode because the second mode enables changing lanes between close vehicles). 
     In some embodiments, a self-driving vehicle comprises a battery compartment comprising a first portion of the self-driving vehicle. A temperature detection system can comprise at least one of an infrared camera, a thermocouple, a resistance temperature detector, a thermistor, a pyrometer, and a thermometer. At least one of the infrared camera, the thermocouple, the resistance temperature detector, the thermistor, the pyrometer, and the thermometer can be configured to detect the first temperature of the first portion of the battery compartment. Program instructions can be configured to cause the self-driving vehicle to stop moving in response to at least one of the infrared camera, the thermocouple, the resistance temperature detector, the thermistor, the pyrometer, and the thermometer detecting that at least one of the first temperature exceeds the temperature threshold and the trajectory of the first temperature exceeds the trajectory threshold. 
     In some embodiments, a self-driving vehicle comprises at least one of a camera configured to detect the indication via image recognition, an antenna configured to detect the indication via receiving a radio communication from a remote computer device of the person, and a seat occupancy sensory configured to detect the indication. 
     In some embodiments, a self-driving vehicle is configured to drive on a road. A vehicle management system can comprise a vehicle guidance system having at least one of a camera, a radar, and a lidar. The vehicle guidance system can be configured to detect objects located outside the self-driving vehicle on the road. Program instructions can comprise a first mode, a second mode, a third mode, and additional modes. 
     In some embodiments, in the first mode, the program instructions are configured to prompt the vehicle management system to drive the self-driving vehicle toward a location. 
     In some embodiments, program instructions are configured to exit the first mode and enter the second mode in response to the temperature detection system detecting that the first temperature exceeds the temperature threshold and the safety system determining that a person is not located inside the self-driving vehicle. 
     In some embodiments, in the second mode, the program instructions are configured to prompt the vehicle guidance system to implement a first stopping mode. 
     In some embodiments, program instructions are configured to exit the first mode and enter the third mode in response to the temperature detection system detecting that the first temperature exceeds the temperature threshold and the safety system determining that the person is located inside the self-driving vehicle. 
     In some embodiments, in the third mode, the program instructions are configured to prompt the vehicle guidance system to implement a second stopping mode configured to enable the self-driving vehicle to come to a stop in less time than the first stopping mode. 
     In some embodiments, the second stopping mode can be configured to enable the self-driving vehicle to move at a greater speed than the first stopping mode. The vehicle management system can be configured to determine a local speed limit, and the second stopping mode can be configured to enable the self-driving vehicle to exceed the local speed limit by a greater amount than the first stopping mode. The second stopping mode can be configured to enable the self-driving vehicle to accelerate faster than the first stopping mode (e.g., to reach a stopping location faster than would be possible in the first stopping mode). The second stopping mode can be configured to enable the self-driving vehicle to decelerate faster than the first stopping mode (e.g., to enable the self-driving vehicle to stop more quickly than would be possible in the first stopping mode). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects, and advantages are described below with reference to the drawings, which are intended to illustrate, but not to limit, the invention. In the drawings, like reference characters denote corresponding features consistently throughout similar embodiments. 
         FIG.  1    illustrates a diagrammatic view that includes a self-driving vehicle configured to use a camera system, according to some embodiments. 
         FIG.  2    illustrates a side view of an interior of the self-driving vehicle with cameras located in several areas, according to some embodiments. 
         FIG.  3    illustrates a side view of an interior of the self-driving vehicle with seats facing each other, according to some embodiments. 
         FIG.  4    illustrates a perspective view of a camera device, according to some embodiments. 
         FIG.  5    illustrates a bottom view of the camera device, according to some embodiments. 
         FIG.  6    illustrates a perspective view of the camera device, according to some embodiments. 
         FIGS.  7  and  8    illustrate diagrammatic views regarding a camera system of a self-driving vehicle, according to some embodiments. 
         FIG.  9    illustrates a diagrammatic view that includes a self-driving vehicle, a camera system, and a smoke detection system, according to some embodiments. 
         FIGS.  10  and  11    illustrate diagrammatic views of a smoke detection system, according to some embodiments. 
         FIGS.  12  and  13    illustrate perspective views of portions of a vehicle, according to some embodiments. 
         FIG.  14    illustrates a diagrammatic view of a temperature detection system, according to some embodiments. 
         FIGS.  15 ,  16 , and  17    each illustrate perspective views of a door of a vehicle, according to some embodiments. 
         FIG.  18    illustrates a side view of a seat of a vehicle, according to some embodiments. 
         FIG.  19    illustrates a perspective view of a seat belt having anchor points that can be bolted to a frame of a self-driving vehicle, according to some embodiments. 
         FIG.  20    illustrates a perspective view of portions of a seat belt, according to some embodiments. 
         FIGS.  21  and  22    illustrate a perspective view of an actuator of a seat belt, according to some embodiments. 
         FIG.  23    illustrates a side view of a vehicle and a diagrammatic view of various devices and systems used in conjunction with the vehicle, according to some embodiments. 
         FIG.  24    illustrates a diagrammatic view of temperature data, according to some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Although certain embodiments and examples are disclosed below, inventive subject matter extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses, and to modifications and equivalents thereof. Thus, the scope of the claims appended hereto is not limited by any of the particular embodiments described below. For example, in any method or process disclosed herein, the acts or operations of the method or process may be performed in any suitable sequence and are not necessarily limited to any particular disclosed sequence. Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding certain embodiments; however, the order of description should not be construed to imply that these operations are order dependent. Additionally, the structures, systems, and/or devices described herein may be embodied as integrated components or as separate components. 
     For purposes of comparing various embodiments, certain aspects and advantages of these embodiments are described. Not necessarily all such aspects or advantages are achieved by any particular embodiment. Thus, for example, various embodiments may be carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other aspects or advantages as may also be taught or suggested herein. 
     Self-driving vehicles will save tens of thousands of lives per year. The majority of vehicle-related deaths are caused by driver errors. Tests have shown that self-driving vehicles nearly eliminate self-inflicted accidents (although they are not immune to accidents caused by human drivers of other vehicles). 
     Self-driving vehicles typically have unlimited attention spans and can process complex sensor data nearly instantaneously. (Alphabet Inc. and Tesla Motors Inc. have built self-driving vehicles.) The ability of self-driving vehicles to save lives is so impressive that society has a moral imperative to develop self-driving technology such that it can be widely adopted. 
     Although self-driving vehicles will unlock many safety benefits, there are several barriers to rapid adoption of self-driving vehicles. Some of the embodiments described herein overcome several of these barriers. 
     Self-driving cars are sometimes referred to as autonomous cars, autonomous vehicles, driverless cars, and driverless vehicles. Various levels of “self-driving” behaviors are available to sense surrounding environments and navigate appropriately (e.g., without hitting objects, in a time-efficient manner). Levels of self-driving vehicles comprise Level 1 (Driver Assistance), Level 2 (Partial Automation), Level 3 (Conditional Automation), Level 4 (High Automation), and Level 5 (Full Automation). Of course, other levels and distinctions are possible. The National Highway Traffic Safety Administration has outlined various levels of self-driving vehicle automation based on information from the Society of Automotive Engineers. 
     Referring now primarily to  FIG.  1   , a vehicle management system  65  can be configured to govern the destinations of a self-driving vehicle  2 . A first rider  1  can have a remote computing device  12  running software configured to enable the first rider  1  to request a ride from a ride service and/or from a particular vehicle. 
     The first rider  1  can open an “app” on an iPhone or Android phone. The “app” can allow the first rider  1  to request a pick-up time and pick-up location. 
     The vehicle management system  65  can communicate with the remote computing device  12  of the first rider  1  directly (e.g., via radio communications such as Bluetooth) or indirectly via intermediary communication systems  5 . Arrows  17 ,  18  indicate communication. (Many additional communication means and methods are compatible with the embodiments described herein.) An antenna  19  of the self-driving vehicle  2  can enable the vehicle management system  65  to communicate with remote computing devices  12 ,  12   b.    
     A second rider  1   b  may request a ride via a second remote computing device  12   b . In some cases, the vehicle management system  65  must choose between providing a ride to a first rider  1 , providing a ride to a second rider  1   b , and/or going to a first location  8  (e.g., to clean the vehicle prior to providing a ride to the first rider  1  and/or to the second rider  1   b ). Arrow  15  indicates the self-driving vehicle  2  driving to the first rider  1  to give the first rider  1  a ride. Arrow  9  indicates the self-driving vehicle  2  driving to the first location  8  instead of driving to pick up the second rider  1   b  right after dropping off the first rider  1 . Arrow  16  indicates the self-driving vehicle  2  eventually picking up the second rider  1   b  (e.g., after the self-driving vehicle  2  is cleaned). 
     A person who owns a car is incentivized to keep the car clean because any mess the person leave in the car will be an annoyance to the person in the future. In contrast, a rider (who does not own the car) can leave a mess in the car without having to see the mess in the future. As a result, people who own self-driving vehicles  2  are motivated to keep the self-driving vehicles  2  clean while non-owning riders are more prone to leaving messes in self-driving vehicles  2 . Owners of vehicles  2  will not want to make their self-driving vehicles  2  available for riders  1 ,  1   b  if the owners are concerned that their vehicles  2  will return messy (after providing the rides). Thus, there is a need for systems that help maintain self-driving vehicles  2 . 
     An owner of a self-driving vehicle  2  will be reluctant to allow other riders to use the self-driving vehicle  2  (e.g., while the owner is at home or work) if the self-driving vehicle  2  will return messy. In addition, if a first rider  1  leaves a mess in the self-driving vehicle  2  (that is not cleaned up), subsequent riders will be unsatisfied with having to ride in a messy self-driving vehicle  2 . 
     One option is to clean the self-driving vehicle  2  between each rider. This option, however, is often cost-prohibitive. Unlike rental cars that are often rented for a day or more at a time, self-driving vehicles  2  can be rented for just a few minutes at a time. Driving the self-driving vehicle  2  to a cleaning station after each few minutes of rental time would require far too many unnecessary cleanings and unnecessary miles driven. Some embodiments described herein enable cleaning the self-driving vehicle  2  only when necessary and otherwise permitting the self-driving vehicle  2  to be used by a series of riders without taking the time to clean the self-driving vehicle  2 . 
     The self-driving vehicle  2  can include two modes. In the first mode, the self-driving vehicle  2  is considered clean and is available to accept a pick-up request. If the maintenance system detects that the self-driving vehicle  2  is unclean inside, then the system can enter a second mode in which the self-driving vehicle  2  is unavailable to accept a pick-up request and instead heads towards a cleaning facility. Once the self-driving vehicle  2  is clean, the system can enter the first mode again. As a result, the self-driving vehicle  2  may drop off the first rider  1 , detect that the self-driving vehicle  2  has an item left behind by the first rider  1 , and then instead of going to pick up the second rider  1   b , can go to a cleaning facility. (Another self-driving vehicle can pick up the second rider  1   b  or the second rider  1   b  can wait for the self-driving vehicle  2  to be cleaned and then can receive a ride from the self-driving vehicle  2 .) 
     The vehicle management system  65  can be a portion of the self-driving vehicle  2 . Communication between the vehicle  2  and the vehicle management system  65  can occur via electrical wires that couple the vehicle management system  65  to other portions of the vehicle  2 . 
     In some embodiments, the vehicle management system  65  is located remotely relative to the self-driving vehicle  2 . Communication between the vehicle  2  and the vehicle management system  65  can occur via wireless communications that travel over intermediary communication systems  5 . 
     In some embodiments, intermediary communication systems  5  are used to perform each step. Intermediary communication systems  5  can comprise wireless networks, Wi-Fi routers, Bluetooth systems, cellular networks, telephone networks, Internet systems, servers, cloud computing, remotely located computers, satellite systems, communication systems, and any other suitable means of enabling communication between the various components of embodiments described herein and/or incorporated by reference. 
     The communicative coupling between the remote computing device  12  and the vehicle management system  65  can be via intermediary communication systems  5 . In other words, intermediary communication systems  5  can communicatively couple the remote computing device  12  and the vehicle management system  65 . This communicative coupling may be via intermittent wireless communications. For example, the vehicle management system  65  may send a wireless message to the remote computing device  12  periodically (e.g., every 10 seconds, every 60 seconds, every 10 minutes). As used herein, “periodically” does not imply that every period has the same duration. In some embodiments, the communicative coupling between the self-driving vehicle  2  and the vehicle management system  65  is via intermediary communication systems  5 . 
     Some embodiments include methods of using the vehicle management system  65  to operate the self-driving vehicle  2 . The vehicle management system  65  is configured to be communicatively coupled with a remote computing device  12 , which is configured to operate software, such as an iPhone application or an Android application adapted to enable a user to control behaviors of the self-driving vehicle  2 . Behaviors can include actions and non-actions of the self-driving vehicle  2 , such as picking up the user at a location, picking up the user at a time based on a schedule of the user or a time based on past pick-up times, remaining idle, driving to a residence of the user, pulling out of a garage, parking the vehicle, getting gas, charging the vehicle, and the like. 
     Referring now primarily to  FIG.  2   , the maintenance system can comprise a camera system having one or more camera devices  10   a ,  10   b ,  10   c ,  10   d ,  11   a ,  11   b . The camera devices  10   a ,  10   b ,  10   c ,  10   d ,  11   a ,  11   b  can include any of the features and capabilities described in the context of the camera device  10 . 
     Camera devices  10   a ,  10   b  can be coupled to a ceiling  20  of the self-driving vehicle  2  such that they include cameras directed towards the first row of seats and/or towards the second row of seats. Camera devices  10   c  can be placed in a trunk area of the self-driving vehicle  2  (e.g., to enable taking pictures and/or videos of items left in the trunk area). 
     A camera device  11   a  can be integrated into the rear-view mirror of the self-driving vehicle  2 . A camera device  11   b  can be integrated into the dash of the self-driving vehicle  2 . Camera devices  10   a ,  10   b ,  10   c ,  11   a ,  11   b  can be placed in any area of the self-driving vehicle  2 . 
     As illustrated in  FIG.  3   , the first and second rows of seats can face towards each other to create a more social riding experience. A camera device  10   d  can be coupled to an interior of the self-driving vehicle  2 . As illustrated in  FIG.  3   , the camera device  10   d  is coupled to the ceiling  20  of the self-driving vehicle  2 . 
       FIG.  4    illustrates a perspective view of a camera device.  FIG.  5    illustrates a bottom view of the camera device  10  coupled to a ceiling  20  of the self-driving vehicle  2 .  FIG.  6    illustrates a perspective view of the camera device  10  with the ceiling  20  hidden to show a top side of the camera device  10 . (The top side is configured to face towards the ceiling  20  of the self-driving vehicle  2 .) 
     The camera device  10  can include multiple cameras  24   a ,  24   b ,  24   c . A first camera  24   a  can be directed in a first direction  25   a  (e.g., towards a front row of seats in the self-driving vehicle  2 ). A second camera  24   b  can be directed in a second direction  25   b  (e.g., towards a middle row of seats in the self-driving vehicle  2 ). A third camera  24   c  can be directed in a third direction  25   c  (e.g., towards a third row of seats in the self-driving vehicle  2 ). 
     Each camera  24   a ,  24   b ,  24   c  can include a wide-angle lens  28  to provide a wider field of view, which can be particularly helpful in the small confines of the self-driving vehicle  2 . The cameras  24   a ,  24   b ,  24   c  can be high-resolution cameras with auto-focus. 
     The camera device  10  can comprise a rider detection system, a communication module (with can include an antenna, a transmitter, and a receiver), a printed circuit board populated with integrated circuits and other electrical components, an image analysis system, a battery, a power management system, a microphone, a speaker, a memory with software configured to carry out the features described herein, and lights configured to illuminate the interior of the self-driving vehicle  2 . 
     The camera device  10  can comprise a smoke detector configured to detect if a rider is smoking (e.g., cigarettes, vaping) inside the self-driving vehicle  2 . Holes  34  enable the smoke to enter the camera device  10  to enable the smoke detector to detect the smoke. Not all the holes  34  are labeled to increase the clarity of other features. 
     The camera device  10  includes buttons that can be configured to enable the rider to interact physically with the camera device. A first button  27   a  is configured to summon emergency responders in response to the rider pressing the button  27   a . The camera device  10  can call “911” and can provide the GPS location of the self-driving vehicle  2  to the emergency responders. 
     A second button  27   b  is configured to call a virtual assistant (or a live human assistant) in response to the rider pressing the button  27   b . The assistant can be configured to answer the rider&#39;s questions. The virtual assistant can use Apple&#39;s “Siri” technology or Amazon&#39;s “Alexa” technology. 
     Pressing a third button  27   c  can notify the maintenance system that the interior of the self-driving vehicle  2  needs to be cleaned. Pressing a fourth button  27   d  can notify the maintenance system that the exterior of the self-driving vehicle  2  needs to be cleaned. 
     The camera device  10  can include an outer housing  33  (e.g., molded from plastic) that snaps onto a molded plastic base plate  31  that is coupled to the ceiling  20  by screws. A hatch  29  can be removed to enable plugging cables into the camera device  10 . The cables can provide electrical power from the self-driving vehicle  2  to the camera device  10 . The cables can also communicatively couple the camera device  10  to other portions of the self-driving vehicle  2  that communicatively couple the self-driving vehicle  2  to the vehicle management system  65 . The cables can exit through holes  30  in the hatch  29 . The camera device  10  can be coupled by wires or wirelessly communicatively coupled to the other elements described herein and/or incorporated by reference. 
     The vehicle management system  65  can be wirelessly communicatively coupled to the self-driving vehicle  2  via intermediary communication systems  5 . The remote computing device  12  can be wirelessly communicatively coupled to the vehicle management system  65  via intermediary communication systems  5 . Intermediary communication systems  5  can comprise wireless networks, cellular networks, telephone networks, Internet systems, servers, cloud computing, remotely located computers, radio communication systems, satellite systems, communication systems, and any other suitable means of enabling wired and/or wireless communication between the remote computing device  12 , the vehicle management system  65 , and/or the self-driving vehicle  2 . 
     In embodiments that include elements such as sending information or otherwise communicating, the remote computing device  12 , the vehicle management system  65 , and the self-driving vehicle  2  can do these elements by using intermediary communication systems  5 . For example, the remote computing device  12 , the vehicle management system  65 , and the self-driving vehicle  2  may send wireless communications and/or receive wireless communications via intermediary communication systems  5 , which can serve as a communication bridge between the remote computing device  12 , the vehicle management system  65 , and the self-driving vehicle  2 . 
       FIG.  7    illustrates a diagrammatic view of the camera device  10  and various images. The camera device  10  can take a first baseline image  35  (e.g., prior to the first rider  1  entering the self-driving vehicle  2 ). The camera device  10  can take a second image  36  in response to the first rider  1  exiting the self-driving vehicle  2 . An image analysis system  70  can subtract the first baseline image  35  from the second image  36  to determine what features are in the second  36  but not in the first baseline image  35 . 
     As shown in the subtraction result image  37 , the first rider  1  left a valuable item  39  behind in the self-driving vehicle  2  and also left trash  40  behind in the self-driving vehicle  2 . The system can send a picture of the valuable item  39  (e.g., a backpack or purse) to the first rider  1  to determine if the first rider  1  wants the system to return the valuable item  39  to the first rider  1 . The system can remove the valuable item  39  prior to picking up a second rider  1   b  (to prevent the second rider from stealing the valuable item  39 ). In some embodiments, the system places the valuable item  39  in the trunk (and locks the trunk) prior to picking up the second rider  1   b.    
     The system can determine the self-driving vehicle  2  needs to be cleaned prior to picking up the second rider  1   b  in response to detecting the trash  40 . 
     Some embodiments use machine vision to detect the items  39 ,  40  left behind by analyzing the second image  36  without analyzing or needing the first baseline image  35 . For example, software can be configured to detect that a backpack has been left in the self-driving vehicle  2  even if no baseline image  35  is available. In some cases, the first baseline image  35  can increase the accuracy and reliability of the system (e.g., by reducing false positives and false negatives). 
     Machine vision can recognize that shapes or even colors are indicative of an item not being part of the vehicle  2  (and thus the item is likely something left behind by a rider). Machine vision can recognize common shapes (e.g., a backpack, a purse, a laptop, a coffee mug, a fast-food bag, a person, a dog). 
       FIG.  8    illustrates a diagrammatic view of the system deciding to pick up a second rider  1   b  or deciding to go to a first location  8  (e.g., to remove an item left behind by a first rider  1 ). The system can detect items  39 ,  40  left behind by analyzing the second image  36  to detect things that should not be in the self-driving vehicle  2  after a rider  1  has left the self-driving vehicle  2 . 
     The system can detect items  39 ,  40  left behind by comparing the second image  36  to a baseline image  35  (of items that should be located in the vehicle  2 ). If the system detects items  39 ,  40  (e.g., as illustrated in image  37 ), then the system can send the self-driving vehicle  2  to the first location  8 . If the system does not detect any items left behind (e.g., as illustrated in image  38 ), then the system can pick up the second rider  1   b.    
       FIG.  9    illustrates some of the elements of the maintenance system. Each of the elements illustrated in  FIG.  9    is optional and is not necessarily present in each embodiment. 
     The maintenance system can include a camera device  10 , which can include memory  75  having many images  35 ,  36 ,  53 ,  54 ,  55 ,  56  taken by the camera device  10 . The camera device  10  can be communicatively coupled to a vehicle management system  65 . 
     The vehicle management system  65  can be communicatively coupled to an image analysis system  70 , a communication system  71 , a smoke detection system  74 , a memory  75  having program instructions  76 , computer systems  7  having processors  77 , a location system  43 , map information  45  configured to help the vehicle  2  navigate to destinations, a traffic monitoring system  46  configured to receive up-to-date traffic information to enable the vehicle management system  65  to choose optimal routes to destinations, and a vehicle control system  78 . 
     The vehicle control system  78  is configured to steer, brake, and accelerate the vehicle  2 . The vehicle control system  78  is also configured to detect roads and obstacles on the roads. 
     The location system  43  is configured to receive a location of the remote computing device  12  associated with the first rider  1  and is configured to receive a location of the remote computing device  12   b  associated with the second rider  1   b . The remote computing devices  12 ,  12   b  can send GPS, indoor location information, and/or other location information to the location system  43  to help the vehicle management system  65  determine where to pick up the rider  1 ,  1   b  and/or determine where to drop off an item left behind by a rider  1 ,  1   b.    
     A user of a remote computing device can complete a number of steps to associate the remote computing device with herself. For example, Apple Inc. makes iPhones, Apple Watches, iPads, laptop computers, and other remote computing devices. A user can associate the iPhone, Apple Watch, iPad, laptop computer, or other remote computing device made by Apple Inc. by (1) turning on the device, (2) using the “Quick Start” option if the user has another device running iOS or selecting the “Set Up Manually” option, (3) activating the device and choosing a Wi-Fi network, (4) setting up “Face ID” and creating a password, and (5) signing in with an “Apple ID.” Of course, other remote computing devices use other methods to associate a remote computing device with a particular user. 
     In some cases, a remote computing device is associated with a user simply because the remote computing device is in the user&#39;s possession and/or is being used by the user. The communication system  71  can include a transmitter  72 , a receiver  73 , and an antenna  19 . The antenna  19  can communicatively couple the vehicle management system  65  to remote computing devices  12 ,  12   b  of riders  1 ,  1   b . The antenna  19  can communicatively couple the vehicle management system  65  to remote computing devices  12   c  of a manager of the vehicle  2 . 
     The vehicle management system  65  can be communicatively coupled to an account  80  of a rider  1  to enable the system to fine the rider  1  for leaving items  39 ,  40  in the vehicle  2 . The fine can be a dollar amount (e.g., $20) such as a trash  40  removal fee or a fee to return a valuable item  39  to a rider  1 . 
     Some embodiments comprise a maintenance system configured to be used with a self-driving vehicle  2 . In some embodiments, maintenance systems comprise a camera system coupled to an interior of the vehicle  2 . The camera system can be configured to take a picture of an item left behind by a first rider. A maintenance system can comprise a vehicle management system configured to autonomously drive the vehicle  2  to a first location  8  to remove the item. 
     As used herein, a self-driving vehicle  2  can “autonomously drive” if the vehicle  2  is steering itself even if a person is providing input regarding navigation of the vehicle  2 . The vehicle  2  can be configured to transport one or more passengers. 
     As used herein, a still image and a video can both be types of pictures. As used herein, a still image and a video can both be types of images. 
     In some embodiments, the camera system comprises a first camera coupled to a ceiling of the vehicle  2  and directed towards a first row of the vehicle  2 , and the camera system comprises a second camera coupled to the ceiling of the vehicle  2  and directed towards a second row of the vehicle  2 . (The first camera can be directed towards a first row if an image taken by the camera shows the first row. The second camera can be directed towards a second row if an image taken by the camera shows the second row.) 
     In some embodiments, the camera system comprises a first camera coupled to a rear-view mirror of the vehicle  2  and directed towards a first row of the vehicle  2 , and the camera system comprises a second camera coupled to a ceiling of the vehicle  2  and directed towards a second row of the vehicle  2 . 
     In some embodiments, the camera system comprises a first camera located in a trunk area of the vehicle  2  such that the first camera is configured to enable an image analysis system  70  to determine if the item is left in the trunk area. 
     In some embodiments, the maintenance system comprises an image analysis system  70  configured to detect the item left behind by comparing a first baseline image  35  taken by the camera system of the interior of the vehicle  2  to a second image  36  taken by the camera system after the first baseline image  35 . Some embodiments comprise determining that the item is present in the second image  36  but not present in the first baseline image  35 . 
     In some embodiments, the vehicle management system is configured to automatically drive the vehicle  2  to the first location  8  to remove the item in response to the image analysis system  70  detecting the item left by the first rider. 
     Some embodiments comprise a communication system  71  configured to send a first wireless communication to a remote computing device  12  associated with the first rider in response to the image analysis system  70  detecting the item left behind by the first rider. The first wireless communication can be configured to notify the first rider that the item was left behind. 
     The communication system  71  can be configured to send the first wireless communication to a remote computing device  12  directly (e.g., via radio communications) or indirectly (e.g., via intermediary communication systems  5 ). 
     In some embodiments, the communication system  71  is configured to send a second wireless communication comprising a third image  53  of the item to the remote computing device  12  in response to the image analysis system  70  detecting the item left behind by the first rider. The third image  53  can enable the rider to see the item on a display of her remote computing device  12 . 
     In some embodiments, the vehicle management system is configured to receive an address of the first location  8  from the remote computing device  12  in response to the communication system  71  sending the first wireless communication. The vehicle management system can be configured to receive the address from the remote computing device directly or indirectly. 
     As used herein, “address” is used broadly and is not limited to a street address. An address can be a Global Positioning System (“GPS”) location and can be any other location indicator. An address can be an indoor location (e.g., a location inside a large shopping center or apartment complex). 
     In some embodiments, the first location  8  is an address at which the first rider has requested to pick up the item. The address can be the rider&#39;s current address. The address can also be a location at which the rider is not currently located by at which the rider (or the rider&#39;s representative) plans to meet the vehicle  2  (or another vehicle  2  carrying the item) to retrieve the item. 
     In some embodiments, the communication system  71  is configured to receive a third wireless communication from the remote computing device  12  associated with the first rider in response to the communication system  71  sending the first wireless communication. The third wireless communication can comprise instructions for shipping the item. The instructions can comprise an address to which the system should ship the item. The instructions can comprise a manner in which the item should be shipped. 
     In some embodiments, the first location  8  is a shipping location (such as a FedEx, UPS, or USPS facility) configured to remove the item from the vehicle  2  and configured to ship the item according to the shipping instructions. The vehicle management system can be configured to enable removing the item from the vehicle  2  once the vehicle  2  is located at the shipping location. The vehicle  2  can unlock a door to enable removing the item. The vehicle  2  can send a smaller, short-range delivery robot to deliver the item to the shipping location. 
     In some embodiments, the vehicle management system is configured to receive the first location  8  of a service area configured to clean the vehicle  2 . The vehicle management system can be configured to drive the vehicle  2  to the service area to remove the item in response to the image analysis system  70  detecting the item left by the first rider. 
     Some embodiments comprise a third image  54  taken by the camera system in response to the vehicle  2  leaving the service area. Some embodiments comprise a communication system  71  configured to send a first wireless communication comprising the third image  54  to a remote computing device  12   c  associated with a manager of the vehicle  2 . The first wireless communication can be configured to enable the manager to verify that the item was removed from the vehicle  2 . 
     Some embodiments comprise a third image  56  taken by the camera system. The image analysis system  70  can be configured to compare the third image  56  to the second image  36  to detect that the item was removed from the vehicle  2 . 
     In some embodiments, the vehicle management system is configured to fine an account of the first rider in response to the image analysis system  70  detecting the item left behind by the first rider. The fine can be a sum imposed as a punishment for leaving the item. 
     In some embodiments, a communication system  71  is configured to send a first wireless communication to a remote computing device  12  associated with the first rider in response to the image analysis system  70  detecting the item left behind by the first rider. The communication system  71  can be configured to send the first wireless communication to a remote computing device  12  directly (e.g., via radio communications) or indirectly (e.g., via intermediary communication systems  5 ). 
     The first wireless communication can comprise a third image  53  taken by the camera system. The third image  53  can be configured to show the item. The first wireless communication can be configured to ask the first rider if the item belongs to the first rider. The communication system  71  can be configured to receive a second wireless communication from the remote computing device  12  in response to the first wireless communication. The second wireless communication can be configured to inform the maintenance system that the first rider is an owner of the item. The maintenance system can comprise a memory configured to record that the first rider is the owner of the item. 
     In some embodiments, the system is configured to automatically drive the vehicle  2  to the rider&#39;s current location (e.g., a GPS location). 
     In some embodiments, the maintenance system comprises a location detection system  43  configured to receive the first location  8  of a remote computing device  12  associated with the first rider to enable the vehicle management system to autonomously drive the vehicle  2  to the first location  8  in response to an image analysis system  70  detecting the item left by the first rider. The image analysis system  70  can be a part of the camera system. The image analysis system  70  can be located remotely from the vehicle  2 . 
     Some embodiments notify a manager of the vehicle  2  that an item was left behind. 
     In some embodiments, the maintenance system comprises an image analysis system  70  configured to detect the item left behind by comparing a first baseline image  35  taken by the camera system of the interior of the vehicle  2  to a second image  36  (of the interior) taken by the camera system after the first baseline image  35 . 
     In some embodiments, the maintenance system comprises a communication system  71  having an antenna  19 , a transmitter  72 , and a receiver  73 . The communication system  71  can be configured to send a first wireless communication to a remote computing device  12   c  associated with a manager of the vehicle  2  in response to the image analysis system  70  detecting the item left behind by the first rider. 
     As used herein, the “manager” can be a person (other than a rider who is just renting the vehicle  2 ) or entity who is responsible for the vehicle  2 . The manager can be an owner of the vehicle  2 . The manager can be a person or entity to whom the owner has entrusted management of the vehicle  2  and/or maintenance of the vehicle  2 . 
     The communication system  71  can be configured to send the first wireless communication to a remote computing device  12  directly (e.g., via radio communications) or indirectly (e.g., via intermediary communication systems  5 ). 
     In some embodiments, the first wireless communication is configured to notify the manager that the item was left behind. The communication system  71  can be configured to send a second wireless communication comprising a third image of the item to the remote computing device  12   c  in response to the image analysis system  70  detecting the item left behind by the first rider. 
     In some embodiments, the vehicle management system is configured to receive a third wireless communication from the remote computing device in response to the communication system  71  sending the first wireless communication. The third second wireless communication can be configured to instruct the vehicle management system to autonomously drive the vehicle  2  to the first location  8  to remove the item. 
     In some embodiments, the vehicle management system is configured to determine that the first rider has exited the vehicle  2 . The vehicle management system can be configured to cause the camera system to take a first interior image of the interior of the vehicle  2  in response to determining that the first rider has exited the vehicle  2 . 
     In some embodiments, the maintenance system further comprises an image analysis system  70  having at least one processor  77  and a memory  75  comprising program instructions (e.g., code modules configured to be executed by one or more computers) that when executed by the at least one processor are configured to cause the image analysis system  70  to detect the item left behind by analyzing the first interior image taken by the camera system after the first rider has exited the vehicle  2 . The first location  8  can be a vehicle cleaning facility. The vehicle management system can be configured to drive the vehicle  2  to the vehicle cleaning facility to remove the item in response to the image analysis system  70  detecting the item. 
     In some embodiments, the vehicle management system comprises a first mode and a second mode. In the first mode, the vehicle management system can be configured to make the vehicle  2  available to accept a pick-up request of a second rider. In the second mode, the vehicle management system can be configured to make the vehicle  2  unavailable to accept the pick-up request at that time (although the vehicle management system  65  can record the pick-up request such that the vehicle  2  can pick-up the person at a future time, such as after the vehicle  2  has been cleaned). 
     A vehicle  2  that is available to accept a pick-up request is ready to go pick up a person. A vehicle  2  that is unavailable to accept a pick-up request is not ready to go pick up a person, but the pick-up can still be scheduled for a future time (e.g., after the vehicle  2  has been cleaned at a cleaning facility or serviced at a service facility). 
     As used herein, “available to accept a pick-up request” means that program instructions and/or another portion of a system place the vehicle  2  in a mode that does not block the vehicle  2  from picking up a person due to a condition of the vehicle (e.g., an item left behind is detected in the vehicle  2 , smoke is detected in the vehicle  2 , an elevated temperature is detected in the vehicle  2 ). 
     As used herein, “unavailable to accept a pick-up request” means that program instructions and/or another portion of a system place the vehicle  2  in a mode that blocks (often temporarily) the vehicle  2  from picking up a person due to a condition of the vehicle (e.g., an item left behind is detected in the vehicle  2 , smoke is detected in the vehicle  2 , an elevated temperature is detected in the vehicle  2 ). 
     The vehicle management system can be configured to be in the second mode from a first time at which the image analysis system  70  detects the item left behind. The vehicle management system can be configured to exit the second mode and enter the first mode in response to at least one of the item being removed, receiving an indication that the vehicle  2  has been cleaned, and the vehicle  2  leaving a vehicle cleaning station. In some embodiments, the indication that the vehicle  2  has been cleaned comprises a wireless communication (e.g., from the cleaning facility) that communicates that the vehicle  2  has been cleaned. 
     In some embodiments, the vehicle management system is configured to determine that the first rider has exited the vehicle  2  in response to (1) receiving a location of a remote computing device  12  associated with the first rider and determining that the location is not inside the vehicle  2 , (2) failing to detect a direct wireless communication from the remote computing device  12  to an antenna of the vehicle  2 , (3) determining, by the image analysis system  70 , that a second interior image does not show the first rider, and/or (4) determining, by the image analysis system  70 , that an infrared image of the interior of the vehicle  2  does not show the first rider. 
     As used herein, a “direct wireless communication” is a wireless communication that does not use intermediary communication systems  5  for communicative coupling between the remote computing device  12  and an antenna  19  that is mechanically coupled to the vehicle  2 . For example, the vehicle  2  can communicate directly with a remote computing device  12  located inside the vehicle  2  via Bluetooth. This Bluetooth communication is one example of a direct wireless communication. Other communication protocols other can Bluetooth can also enable direct wireless communication. Other radio communication systems can enable direct wireless communication. 
     In some embodiments, the maintenance system comprises at least one processor  77  and a memory  75  comprising program instructions that when executed by the at least one processor cause the maintenance system to (1) compare a first baseline image  35  taken by the camera system of the interior of the vehicle  2  to a second image  36  taken by the camera system after the first baseline image  35  to detect the item left behind by the first rider, and/or (2) drive, by the vehicle management system, the vehicle  2  to the first location  8  to remove the item in response to the detecting the item. The program instructions can comprise code modules configured to be executed by one or more computers located in the vehicle  2  and/or located away from the vehicle  2 . 
     In some embodiments, the first location  8  is a first vehicle cleaning facility. The program instructions can be configured to select the first vehicle cleaning facility based at least in part on determining a distance from the vehicle  2  to the first vehicle cleaning facility and/or based at least in part on determining that the first vehicle cleaning facility is approved by a manager of the vehicle  2 . 
     A manager can receive a list of vehicle cleaning facilities. The list can include prices, services offered, user reviews, and locations. The manager can then select which of the vehicle cleaning facilities she approves. Once approved, the system can select which of the approved facilities to use to clean the vehicle  2  based on many factors including which facility is open, which facility is closest to the current location of the vehicle  2 , and which facility will be closest to an anticipated future location of the vehicle  2 . 
     The memory  75  can comprise a list of vehicle cleaning facilities that were approved by the manager of the vehicle  2 . The list can include a location of each cleaning facility. The program instructions can be configured to choose a cleaning facility that was previously approved by the manager and is located near the current location of the vehicle  2 . 
     In some embodiments, the program instructions are configured to send a first wireless communication to a remote computing device  12  associated with the first rider in response to detecting the item. The first wireless communication can comprise an image of the item. The program instructions can be configured to receive a second wireless communication from the remote computing device  12  in response to sending the first wireless communication. The second wireless communication can comprise an instruction (e.g., from the first rider) to return the item. The program instructions can be configured to drive, by the vehicle management system, the vehicle  2  to the first location  8  in response to the instruction. 
     One barrier to owners of self-driving vehicles being willing to allow other people to ride in their vehicles (e.g., when the owner is not present) is that owners are concerned riders will smoke in their vehicles. Smoking can leave a lasting smell that is bothersome to vehicle owners and bothersome to subsequent riders. 
     When a self-driving vehicle gives rides to riders, there may be times when an owner, manager, or driver is not in the vehicle. As a result, the rider might feel free to smoke in the vehicle. Smoking in the vehicle, however, could substantially damage the value of the vehicle and undermine the experience of future riders. Thus, there is a need for systems and methods are detect smoke inside self-driving vehicles. 
     Many types of smoke detection systems can be used inside vehicles. Some embodiments use optical smoke detectors, ionization smoke detectors, and camera-based smoke detectors (that use machine vision, image recognition, and/or artificial intelligence to recognize smoke). Smoke detectors can be coupled to a ceiling inside the vehicle (because smoke can float upward) and can be coupled to any location inside the vehicle. In some embodiments, smoke detectors are integrated into a camera system and/or into the dash of the vehicle. 
     There are many types of optical smoke detectors. In some types, an infrared light beam from a light-emitting diode (“LED”) is projected into a chamber. Holes in an outer covering of the smoke detector can allow smoke to move into the chamber. The chamber can include an electronic light detector (e.g., a photocell) that generates electricity in response to light hitting the electronic light detector. The LED can be oriented in such a way that it is not pointed at the light detector. When smoke enters the chamber, however, the smoke can cause the light beam from the LED to be scattered. Some of the scattered light can hit the light detector. An electronic circuit can monitor the light detector and can determine whether infrared light is hitting the detector. The smoke detector can interpret infrared light hitting the detector as an indication of smoke. The smoke detector can be configured to emit an audio alarm and/or send a wireless communication in response to infrared light hitting the detector. 
     Some embodiments use photoelectric smoke detectors. Photoelectric smoke detectors can be well suited to detecting certain types of smoke. 
     Some smoke detection system embodiments comprise ionization smoke detectors. There are many types of ionization smoke detectors. In some embodiments, ionization smoke detectors have a chamber. Holes in an outer housing of the smoke detector can allow smoke to enter the chamber. The chamber can be filled with ions. The ions can come from a chemical element called americium. 
     Americium can release tiny radioactive particles (called alpha particles), which leak into the detection chamber. As the radioactive particles from the americium enter the chamber, the radioactive particles can collide with air molecules and turn them into positively charged ions and negatively charged electrons. The ions and electrons can move in opposite directions between two electrodes. As long as the ions and electrons are moving, a current flows between the electrodes, which a circuit in the smoke detector can interpret as being an indication that smoke is not present in the vehicle. 
     If smoke is present, however, smoke particles get into the detector and start to clog up the ionization chamber. The smoke particles attach themselves to the ions and effectively shut off the electric current. The circuit in the detector can detect that change and can interpret the lack of the electrical current as an indication that smoke is present in the vehicle. 
     When smoke is no longer present in the chamber, the current between the electrodes can resume, which the smoke detector can determine is an indication of the smoke no longer being present in the vehicle. 
     Some embodiments have a smoke detection system that uses a camera system to “see” the smoke (and thereby detect the smoke). The camera system can see the smoke by recognizing the distinct shape of smoke moving through the air. For example, a cloud of smoke inside a vehicle has a particular shape that a camera system can recognize as an indication of smoke being present in the vehicle. 
     The cloud of smoke created by electronic cigarette use has a different appearance (e.g., a different shape, different movement patterns, and different optical properties) than the appearance (e.g., shape, movement patterns, and optical properties) of smoke created by non-electric cigarette smoking. The camera system can thus “see” the difference between a cloud of smoke created by electronic cigarette use and the cloud of smoke created by non-electronic cigarette use. 
     The maintenance system can include at least one processor and a memory comprising program instructions that when executed by the at least one processor cause the smoke detection system to determine whether the smoke is from electronic cigarette use or is from non-electronic cigarette use by analyzing the appearance (e.g., shape, movement patterns, and optical properties) of the smoke. 
     In some embodiments, the smoke detection system comprises a camera system and an image analysis system configured to detect the smoke inside the vehicle by comparing a first baseline image taken by the camera system of an interior of the vehicle to a second image taken by the camera system (of the interior of the vehicle) after the first baseline image. 
     The image analysis system can include at least one processor and a memory comprising program instructions that when executed by the at least one processor cause the image analysis system to compare a first baseline image taken by the camera system of the interior of the vehicle to a second image taken by the camera system after the first baseline image to detect the smoke. The smoke can appear in the second image (e.g., taken by the camera while the rider is smoking) but not appear in the first image (e.g., taken by the camera before the rider started smoking). A visible difference between the two images can be a cloud of smoke. 
     Many different types of smoke detectors can analyze a size of a particle of the smoke. A small particle of smoke can be indicative of the smoke being from non-electronic cigarette use. A large particle of smoke can be indicative of the smoke being from electronic cigarette use. 
     As used herein, “smoke” is used broadly to include smoke generated by burning cigarettes and to include aerosol (sometimes called “vapor”) created by electronic cigarette use (sometimes called “vaping”). 
     As used herein, “cigarettes” are used to burn materials such that the user can inhale the smoke. Cigarettes can burn many substances including, but not limited to tobacco, marijuana, other psychoactive materials, and other materials that people burn to inhale. As used herein, “cigarette” is used broadly and can include a roll of material enclosed in paper and meant to be smoked, but also includes many other smoking devices such as cigars, pipes, bongs, and bubblers. 
     As used herein, “electronic cigarettes” are used to heat a liquid or other substance to generate an aerosol (which is sometimes called a “vapor”). Some liquids include nicotine, propylene glycol, glycerin, flavorings, and drugs. As used herein, “electronic cigarette” is used broadly and includes all the diverse shapes and types of electronic cigarettes. Some electronic cigarettes include a mouthpiece, a cartridge (tank), a heating element (atomizer), a microprocessor, and a battery. As used herein, “electronic cigarettes” include vaping devices of all shapes, styles, and sizes and is not limited to vaping devices that have a slim, cylindrical appearance. 
     Nittan Europe Limited is registered in England and makes a dual optical smoke detector called the EV-DP. Using the scattered light principle inherent in optical detectors, the dual optical smoke detector uses both infrared LEDs and blue LEDs to provide an accurate measurement of particles within the chamber of the smoke detector. By calculating the ratio of these light sources, which operate at different wavelengths, the dual optical smoke detector can determine the particle size and thus distinguish between smoke due to combustion (of cigarettes) and smoke due to aerosol generated by non-combustion products (e.g., vaping devices). 
     The entire contents of the following patent are incorporated by reference herein: U.S. Pat. No. 6,011,478; issued Jan. 4, 2000; and entitled Smoke Sensor and Monitor control System. 
     U.S. Pat. No. 6,011,478 describes smoke detection systems that analyze the sizes of particles of smoke. The components described in U.S. Pat. No. 6,011,478 that analyze the sizes of particles of smoke are included in the camera device  10  described herein. 
     The smoke detection system can also comprise an optical smoke detector (e.g., the EV-DP) configured to analyzing a particle size of the aerosol. The smoke detection system can detect electronic cigarette aerosol by analyzing a particle size of the aerosol and determining that the particle size is indicative of electronic cigarette use (e.g., the particle size is larger than is typical for combustion-generated smoke). 
     The smoke detection system can determine if the particle size is smaller than a predetermined threshold by directly determining that the particle size is smaller than the threshold. The smoke detection system can also determine if the particle size is smaller than a predetermined threshold by determining that the particle size is larger than the threshold (because by knowing that the particle size is larger than the threshold, the system also effectively knows that the particle size is not smaller than the threshold). 
     The smoke detection system can determine if the particle size is larger than a predetermined threshold by directly determining that the particle size is larger than the threshold. The smoke detection system can also determine if the particle size is larger than a predetermined threshold by determining that the particle size is smaller than the threshold (because by knowing that the particle size is smaller than the threshold, the system also effectively knows that the particle size is not larger than the threshold). 
     In some embodiments, rather than use the process of elimination, the smoke detection system actually measures the particles and then determines if the size of each particle is smaller or larger than the threshold. The threshold can be chosen such that being smaller than the threshold is indicative of the particle being cigarette smoke and being larger than the threshold can be indicative of the particle being electronic cigarette aerosol. The maintenance system&#39;s reaction to detecting cigarette smoke can be different (e.g., more extreme) than the maintenance system&#39;s reaction to electronic cigarette aerosol (which is typically less damaging to vehicles). 
       FIG.  10    illustrates a diagrammatic view of a smoke detection system  74 . When the camera device  10  includes at least one smoke detector, the camera device  10  can be a smoke detection system  74 . Many types of smoke detectors can be used including ionization smoke detectors  90 , optical smoke detectors  91 , camera-based smoke detectors (which can include an image analysis system  70  and cameras  24   a ,  24   b ,  24   c ), and any other type of smoke detector. 
     The ionization smoke detector  90 , the optical smoke detector  91 , and the image analysis system  70  can be part of the camera device  10  (e.g., such that they are located inside the device  10 ). In some embodiments, the ionization smoke detector  90 , the optical smoke detector  91 , and/or the image analysis system  70  are located outside of the camera device  10 , but are still located inside the vehicle  2 . 
     In some embodiments, the image analysis system  70  is located remotely relative to the vehicle  2  such that a camera  24   a  takes images (which can be videos or still images) of the inside of the vehicle  2  and a communication system  71  sends the images to the image analysis system  70  (which can include a server located far from the vehicle  2 ). The communication system  71  can send the images to the image analysis system  70  via intermediary communication systems  5 . The image analysis system  70  can analyze the images to determine if the images show smoke. 
     The smoke detection system  74  can be coupled to the vehicle  2  (e.g., to a ceiling of the vehicle  2 ). The smoke detection system  74  can detect smoke inside the vehicle  2 .  FIG.  10    illustrates two clouds of smoke  88 ,  89 . A first cloud of smoke  88  includes small particles (which are illustrated as small circles). A second cloud of smoke  89  includes large particles (which are illustrated as large circles). The smoke detection system  74  can analyze the size of the particles in many different ways. 
     The smoke detection system  74  can use both infrared LEDs and blue LEDs to provide an accurate measurement of particles within the chamber of the smoke detector. By calculating the ratio of these light sources, which operate at different wavelengths, the smoke detection system  74  can determine the particle size and thus distinguish between smoke due to combustion (of cigarettes) and smoke due to aerosol generated by non-combustion products (e.g., vaping devices). 
     The entire contents of the following patent are incorporated by reference herein: U.S. Pat. No. 6,011,478; issued Jan. 4, 2000; and entitled Smoke Sensor and Monitor Control System. The smoke detection system  74  can use any of the embodiments described in U.S. Pat. No. 6,011,478 to analyze the size of the particles in smoke to determine if the particles are larger or smaller than a predetermined threshold. The threshold can be chosen such that detecting particles larger than the threshold is indicative of the smoke being from non-combustion (e.g., electronic cigarette aerosol) and detecting particles smaller than the threshold is indicative of the smoke being from combustion (e.g., cigarette smoking). 
     Detecting particles smaller than the threshold (e.g., as indicated by the first cloud of smoke  88 ) can cause the system to label the event as a combustion (e.g., cigarette smoking) event. The system can send a wireless communication  98  (which may be via intermediary communication systems  5 ) to a remote computing device  12   c  of a manager of the vehicle  2 . The manager can be an entity responsible for the maintenance of the vehicle  2 . The manager can be an owner of the vehicle  2 . 
       FIG.  10    illustrates the remote computing device  12   c  as a desktop computer, but the remote computing device  12   c  can be a server, the Cloud, any type of remote computing device described herein or incorporated by reference, or any other suitable computer. 
     The first wireless communication  98  (which can comprise many wireless communication sessions) can be configured to enable the remote computing device  12   c  to show an image  94  of the rider  1  who was smoking in the vehicle  2 . The image  94  can show the rider  1  in the act of smoking in the vehicle  2  (e.g., to serve as proof that the rider  1  was smoking in the vehicle  2 ). 
     The wireless communication  98  (which can comprise many wireless communication sessions) can comprise data regarding the smoking event. The data can include the name of the rider  1 , an account number of the rider  1 , a ride number, and/or any other data that serves to identify the rider  1 . The wireless communication  98  can also comprise data regarding whether the smoke detected by the smoke detection system  74  was due to non-combustion (e.g., electronic cigarette aerosol) or combustion (e.g., cigarette smoking). The fine due to detecting combustion can be higher than the fine due to non-combustion due to the greater harm caused by combustion smoke (rather than non-combustion smoke) inside the vehicle  2 . The system&#39;s reaction to combustion smoke can be more extreme than the system&#39;s reaction to non-combustion smoke. 
     The remote computing device  12   c  can be configured to show data  96  regarding the rider  1  and the smoking event of the rider  1 . 
     Detecting particles larger than the threshold (e.g., as indicated by the second cloud of smoke  89 ) can cause the system to label the event as a non-combustion (e.g., vaping) event. The system can send a second wireless communication  99  (which may be via intermediary communication systems  5 ) to a remote computing device  12   c  of a manager of the vehicle  2 . The remote computing device  12   c  shown in the lower right of  FIG.  10    illustrates information displayed by the remote computing device  12   c  in response to the second wireless communication  99  regarding the non-combustion smoking event. 
     The second wireless communication  99  (which can comprise many wireless communication sessions) can be configured to enable the remote computing device  12   c  to show an image  95  of the rider  1   b  who was smoking in the vehicle  2 . The image  95  can show the rider  1   b  in the act of smoking in the vehicle  2  (e.g., to serve as proof that the rider  1   b  was smoking in the vehicle  2 ). 
     The second wireless communication  99  (which can comprise many wireless communication sessions) can comprise data regarding the smoking event. The data can include the name of the rider  1   b , an account number of the rider  1   b , a ride number, and/or any other data that serves to identify the rider  1   b.    
     The second wireless communication  99  can also comprise data regarding whether the smoke detected by the smoke detection system  74  was due to non-combustion (e.g., electronic cigarette aerosol) or combustion (e.g., cigarette smoking). 
     The remote computing device  12   c  can be configured to show data  97  regarding the rider  1   b  and the smoking event of the rider  1   b.    
       FIG.  11    illustrates a diagrammatic view of a smoke detection system  74 .  FIG.  11    includes a small circle in the ceiling of the vehicle  2 . This small circle illustrates one location (out of many) in which the smoke detection system  74  can be placed inside the vehicle  2 . The smoke detection system  74  can be located inside the cabin of the vehicle  2 . 
     A remote computing device  12   c  of a manager  3  of the vehicle  2  can receive wireless communications from the vehicle  2  (in some cases via intermediary communication system  5 ) in response to the vehicle  2  detecting smoke. 
     The vehicle  2  can include a window  82  and a motor  81  configured to move the window  82  (of the vehicle  2 ) up and down. The motor  81  can be embedded in a door of the vehicle  2 . 
     The vehicle  2  can include a fan  83  configured to circulate air inside the cabin of the vehicle  2 . In some vehicles  2 , the fan  83  is embedded inside a vent inside the dash. 
     The vehicle  2  can include a temperature management system  85  having a thermometer, an air conditioner, a heater, and a ventilation system  84 . The temperature management system  85  can be configured to control an ambient temperature inside the cabin of the vehicle  2  by heating or cooling air inside the cabin. In some embodiments, the temperature management system  85  is configured to heat the air inside the cabin to approximately 74 degrees Fahrenheit (e.g., on cold days) and is configured to cool the air inside the cabin to approximately 74 degrees Fahrenheit (e.g., on hot days). In other embodiments, however, the temperature management system  85  is configured to deliberately make the ambient temperature inside the cabin uncomfortably hot or cold in response to the smoke detection system  74  detecting smoke inside the cabin. 
     On a hot day (with an outside temperature greater than 74 degrees Fahrenheit), the temperature management system  85  can heat the cabin air to a temperature that is greater than 84 degrees Fahrenheit and/or greater than 90 degrees Fahrenheit. 
     On a cold day (with an outside temperature less than 74 degrees Fahrenheit), the temperature management system  85  can cool the cabin air to a temperature that is less than 64 degrees Fahrenheit, less than 50 degrees Fahrenheit, and/or less than 40 degrees Fahrenheit. 
     The vehicle  2  can include a speaker  86  configured to emit sounds (e.g., music, audio commands) inside the cabin of the vehicle  2 . In some vehicles  2 , the speaker  86  is embedded inside the dash of the vehicle  2 . In some vehicles  2 , the speaker  86  is located along the top, bottom, or side of the cabin of the vehicle  2  and arranged and configured to emit sounds towards the seats. The vehicle  2  can also include a microphone  186  configured to record sounds, such as a verbal response, inside the cabin of vehicle  2 . In some vehicles  2 , the microphone  186  is embedded inside the dash of the vehicle  2 . In some vehicles  2 , the microphone  186  is located along the top, bottom, or side of the cabin of the vehicle  2  and arranged and configured to record sounds from rider(s) in the seat(s). 
     The vehicle  2  can include a rain sensor  87 . The rain sensor  87  can be based on the principle of total internal reflection. An infrared light is beamed at a 45-degree angle into the windshield from the interior of the vehicle  2  (e.g., just behind the windshield of the vehicle  2 ). If the windshield glass is wet, less light makes it back to a light sensor than if the windshield glass is dry. Measuring the light that makes it back to the light sensor provides an indication of whether it is raining (because the windshield is wet when it is raining). 
     The following U.S. patents, the entire contents of which are incorporated herein by reference, describe additional types of rain sensors  87  that can be used with the embodiments described herein: U.S. Pat. Nos. 4,578,995; 4,584,508; 4,987,296; 6,392,218; and 6,341,523. Some embodiments use other types of rain sensors. 
     Some rain sensor embodiments use a camera (e.g., looking out of a window of the vehicle) to “see” if it is raining outside the vehicle. For example, in 2017 Tesla introduced an update that enabled their cars to utilize onboard cameras to passively detect rain without the use of a dedicated sensor. 
     Some embodiments comprise a maintenance system configured to be used with a self-driving vehicle  2 . The maintenance system can use a smoke detector to detect smoke inside the vehicle  2  and then can take actions in response to detecting the smoke. 
     A maintenance system can comprise a smoke detection system  74  configured to detect smoke inside a cabin of the vehicle  2 ; a communication system  71  configured to send a first wireless communication to a remote computing device  12   c  associated with a manager of the vehicle  2  in response to the smoke detection system  74  detecting the smoke; and/or a vehicle management system  65  configured to autonomously drive the vehicle  2 . 
     The vehicle management system  65  can be mechanically coupled to the vehicle  2 . In some embodiments, the vehicle management system  65  is located remotely relative to the vehicle  2 . In some embodiments, a portion of the vehicle management system  65  is mechanically coupled to the vehicle  2  and another portion of the vehicle management system  65  is not mechanically coupled to the vehicle  2  but is communicatively coupled to the vehicle  2 . 
     A vehicle management system  65  can be configured to autonomously drive the vehicle  2  even if a rider provides some input such as a destination and even if the rider is told to intervene to drive the vehicle  2  in certain circumstances. 
     In some embodiments, the smoke detection system  74  comprises a camera system and an image analysis system  70  configured to detect the smoke inside the vehicle  2  by comparing a first baseline image taken by the camera system of an interior of the vehicle  2  to a second image taken by the camera system (of the interior of the vehicle  2 ) after the first baseline image. 
     In some embodiments, a maintenance system comprises a memory  75  having an identification of a first rider of the vehicle  2 . The communication system  71  can comprise an antenna  19 , a transmitter  72 , and/or a receiver  73 . The communication system  71  can be configured to send the identification of the first rider to the remote computing device  12   c  of the manager in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . 
     Many different types of identifying information can be used as identification of the rider. In some embodiments, the identification is a name of the rider, a picture of the rider, a number or code that represents the rider&#39;s account, a credit card number, a social security number, a driver&#39;s license number, a number or code that represents the ride that the rider took, and/or any information configured to help identify the rider. 
     In some embodiments, a maintenance system comprises a camera system coupled to an interior of the vehicle  2 . The camera system can be configured to take a picture of a first rider smoking. The communication system  71  can be configured to send the picture of the first rider smoking to the remote computing device  12   c.    
     In some embodiments, the camera system comprises a first camera directed towards a first row of the vehicle  2 . The first camera can be configured to take the picture in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . 
     In some embodiments, the smoke detection system  74  comprises an ionization smoke detector  90  configured to detect cigarette smoking. The smoke detection system  74  can also comprise an optical smoke detector  91  configured to detect electronic cigarette aerosol by analyzing a particle size of the aerosol and determining that the particle size is indicative of electronic cigarette use. 
     As used herein, smoke can include aerosol generated by “vaping” and also smoke generated by burning cigarettes. 
     Electronic cigarettes can include all types of devices used to heat a liquid to generate an aerosol, commonly called a “vapor,” that the user inhales. 
     Cigarettes can be used to burn many psychoactive materials including tobacco and marijuana. 
     In some embodiments, the smoke detection system  74  comprises at least one optical smoke detector  90  configured to analyze a particle size of the smoke. The communication system  71  is configured to send the first wireless communication identifying the smoke as an aerosol in response to the smoke detection system  74  determining that the particle size is greater than a predetermined threshold. The communication system  71  can be configured to send the first wireless communication identifying the smoke as cigarette smoking in response to the smoke detection system  74  determining that the particle size is less than the predetermined threshold. 
     The first wireless communication can comprise multiple wireless communications and is not limited to a single communication instance. The first wireless communication can comprise many wireless communication sessions. 
     In some embodiments, a camera system is coupled to an interior of the vehicle  2 . The camera system can be configured to take a picture of a first rider smoking. The communication system  71  can be configured to send the picture of the first rider smoking to the remote computing device  12   c . The first wireless communication  98  can be configured to enable the remote computing device  12   c  to display the picture of the first rider smoking and to display an indication  96  of whether the smoke is due to the aerosol or the cigarette smoking. 
     The vehicle management system  65  can automatically take many actions in response to the smoke detector detecting smoke. 
     In some embodiments, the vehicle management system  65  comprises a motor  81  configured to open a window  82  of the vehicle  2 . The vehicle management system  65  can be configured to use the motor  81  to automatically roll down the window  82  in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . 
     In some embodiments, the vehicle management system  65  comprises a ventilation system  84  having a fan  83  to push air in the cabin. The fan  83  can be located inside the dash of the vehicle  2  such that the fan  83  pushes air in the cabin by pushing air through a vent and into the cabin. The vehicle management system  65  can be configured to automatically increase a rate at which the ventilation system  84  pushes outside air into the cabin of the vehicle  2  in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . In several embodiments, the rate is increased by increasing a rotational speed of the fan  83 . 
     In some embodiments, the vehicle management system  65  comprises a ventilation system  84 , and the vehicle management system  65  is configured to use the ventilation system  84  to automatically inject outside air into the cabin of the vehicle  2  in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . 
     In some embodiments, the vehicle management system  65  comprises a temperature management system  85  having a thermometer and having at least one of an air conditioner, a heater, and a ventilation system  84  having a fan  83  to circulate air in the cabin. The fan  83  can be located inside a vent inside the dash of the vehicle  2  such that the fan  83  is configured to circulate air in the cabin by pushing air out from a vent. The vehicle management system  65  can be configured to at least one of increase and decrease an ambient temperature inside the cabin by at least ten degrees Fahrenheit in response to the smoke detection system  74  detecting the smoke inside the vehicle  2  to decrease a comfort level of a first rider. 
     In some embodiments, the vehicle management system  65  is configured to decrease an ambient temperature inside the cabin by at least ten degrees Fahrenheit and/or by at least twenty degrees Fahrenheit in response to the smoke detection system  74  detecting the smoke inside the vehicle  2  to decrease a comfort level of a first rider. The vehicle management system  65  can be configured to increase an ambient temperature inside the cabin by at least ten degrees Fahrenheit and/or by at least twenty degrees Fahrenheit in response to the smoke detection system  74  detecting the smoke inside the vehicle  2  to decrease a comfort level of a first rider. 
     In some embodiments, a maintenance system is configured to be used with a self-driving vehicle  2 . A maintenance system can comprise a smoke detection system  74  coupled to the vehicle  2  and configured to detect smoke inside a cabin of the vehicle  2 . The smoke detection system  74  can be coupled to the vehicle  2  by being placed inside the vehicle  2 , being attached to a roof of an interior of the vehicle  2 , and/or coupled to the vehicle  2  in any suitable way configured to enable the smoke detection system  74  to detect smoke inside the vehicle  2 . A maintenance system can comprise a vehicle management system configured to autonomously drive the vehicle  2 . 
     In some embodiments, a vehicle management system is configured to respond in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . Embodiments described herein include many different ways in which the vehicle management system can respond to the smoke detection system  74  detecting smoke inside the vehicle  2 . Responses can protect the safety of riders inside the vehicle  2  and/or can reduce smoke damage to the vehicle  2 . 
     In some embodiments, a maintenance system comprises a communication system  71  configured to send a first wireless communication to a remote computing device in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . The remote computing device can be associated with a manager of the vehicle  2  such that the first wireless communication is configured to notify the manager regarding the smoke inside the vehicle  2 . 
     In some embodiments, the vehicle management system comprises a temperature management system  85 . The temperature management system  85  can comprise a thermometer, an air conditioner, a heater, and a ventilation system  84 . The ventilation system  84  can comprise a fan  83  configured to circulate air in the cabin of the vehicle  2 . The vehicle management system can be configured to increase and/or decrease an ambient temperature inside the cabin by at least ten degrees Fahrenheit in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . In response to the smoke detection system  74  detecting the smoke inside the vehicle  2 , the vehicle management system can increase and/or decrease the ambient temperature to decrease a comfort level of a first rider. Making the rider hot or cold can decrease the comfort level of the first rider, which can discourage the rider from continuing to smoke in the vehicle  2 . 
     In some embodiments, the maintenance system comprises at least one processor  77  and at least one memory  75  having program instructions  76  configured to be executed by the at least one processor  77 . The program instructions  76  can be configured to cause the vehicle management system to at least one of increase and decrease the ambient temperature by at least ten degrees Fahrenheit and by less than thirty degrees Fahrenheit. In response to the smoke detection system  74  detecting smoke inside the vehicle  2 , the program instructions  76  can cause the vehicle management system to increase and/or decrease the ambient temperature (e.g., by at least ten degrees Fahrenheit and/or by less than thirty degrees Fahrenheit) to decrease the comfort level of a rider inside the vehicle  2 . 
     In some embodiments, the vehicle management system comprises a speaker  86  and/or a display screen  93 . At least one of the speaker  86  and the display screen  93  can be configured to provide at least one of audio instructions and visual instructions to the first rider. At least one of the audio instructions and the visual instructions can be configured to instruct the first rider to cease smoking in order to enable changing the ambient temperature to increase the comfort level. For example, the instructions can tell the rider that the cabin of the vehicle will remain uncomfortably hot or uncomfortably cold until the rider stops smoking in the vehicle  2 . 
     In some embodiments, the smoke detection system  74  is configured to analyze a particle size of the smoke to determine if the particle size is smaller than a predetermined threshold. The vehicle management system can be configured to increase and/or decrease the ambient temperature inside the cabin (to decrease the comfort level of the first rider) in response to the maintenance system detecting the smoke inside the vehicle  2  and determining that the particle size is smaller than the predetermined threshold. 
     In some embodiments, the vehicle management system is configured to automatically at least partially restore (increase) the comfort level in response to the smoke detection system  74  no longer detecting the smoke inside the vehicle  2 , detecting that a concentration of the smoke is less than a predetermined threshold, detecting that a concentration of the smoke is decreasing, and/or detecting that a concentration of the smoke has decreased by at least a predetermined amount and/or ratio. 
     For example, if the program instructions caused the cabin temperature to fall from 73 degrees Fahrenheit to 50 degrees Fahrenheit (in response to detecting smoke in the cabin), then the program instructions can cause the cabin temperature to increase to 70 degrees Fahrenheit (to at least partially restore the comfort level) in response to the smoke detection system  74  no longer detecting the smoke inside the vehicle  2 . If the program instructions caused the cabin temperature to rise from 73 degrees Fahrenheit to 90 degrees Fahrenheit (in response to detecting smoke in the cabin), then the program instructions can cause the cabin temperature to decrease to 73 degrees Fahrenheit (to restore the comfort level) in response to the smoke detection system  74  no longer detecting the smoke inside the vehicle  2 . 
     In some embodiments, the vehicle management system  65  is configured to determine a local speed limit and is configured to automatically reduce a speed of the vehicle  2  below the local speed limit in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . 
     In some embodiments, the vehicle management system  65  determines the local speed limit by receiving the local speed limit from a remote system (e.g., via a wireless communication to the vehicle management system  65 ). 
     In some embodiments, the vehicle management system  65  comprises data regarding speed limits of each area (e.g., street section) of a map. The vehicle management system  65  can determine the local speed limit by determining a location of the vehicle  2  and then using that location to determine which speed limit applies to the area of the location. 
     Some embodiments include reducing the speed so much that the vehicle  2  stops (e.g., such that the vehicle  2  is parked). The vehicle management system  65  can be configured to determine a suitable parking location in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 , and the vehicle management system  65  can be configured to park the vehicle  2  in the parking location in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . 
     In some embodiments, the vehicle management system  65  comprises a speaker  86 . The speaker  86  can be configured to emit audio commands instructing a first rider of the vehicle  2  to cease smoking in order to cause the vehicle management system  65  to increase the speed and/or start moving again after being stopped in a parking location. The audio commands can be words such as, “John, the car has stopped because it has detected that you are smoking. The car will not start moving again until you stop smoking. You have been fined $50 and will be fined an even larger amount if you do not stop smoking within 60 seconds.” 
     Getting the rider to stop smoking right away is advantageous because additional time smoking will result in additional damage to the vehicle  2 . A vehicle  2  that has been smoked in for 10 seconds typically will not smell as bad as a vehicle  2  that has been smoked in for 10 minutes. 
     Some embodiments comprise a first financial penalty for smoking and additional financial penalties for continuing to smoke inside the vehicle. The vehicle  2  can be configured to provide a ride to a first rider. The vehicle management system  65  can be configured to fine an account  80  of the first rider a first amount in response to the smoke detection system detecting the smoke inside the vehicle  2 . The vehicle management system  65  can be configured to notify the first rider that the account  80  will be fined a second amount if the smoke detection system detects the smoke at a later time during the ride. The vehicle management system  65  can be configured to fine the account  80  the second amount in response to the smoke detection system detecting the smoke at the later time during the ride. The second amount can be greater than the first amount. The second amount can be at least forty percent greater than the first amount such that the large second amount is a strong deterrent to the rider deciding to continue smoking in the vehicle  2 . 
     In some embodiments, the vehicle management system  65  can be configured to fine an account  79  of a second rider a certain amount of money (e.g., a financial fine) in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . 
     In some embodiments, the vehicle  2  is configured to drive a first rider to a destination selected by the first rider. The vehicle management system  65  can be configured to cease driving towards the destination in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . The vehicle  2  can pull over to the side of the road. The vehicle  2  can determine a suitable parking location and then can cease driving towards the destination by going to the parking location. The vehicle  2  can cease driving towards the destination by driving away from the destination. The vehicle management system  65  can be configured to continue driving towards the destination once the smoke detection system  74  no longer detects the smoke inside the vehicle  2 . 
     In some embodiments, the vehicle management system  65  is configured to fine an account  80  of a first rider of the vehicle  2  in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . The smoke detection system  74  can be configured to analyze a particle size of the smoke to determine if the particle size is larger than a predetermined threshold. The vehicle management system  65  can be configured to fine the account  80  a first amount if the particle size is larger than the predetermined threshold. The vehicle management system  65  can be configured to fine the account  80  a second amount if the particle size is smaller than the predetermined threshold. The second amount can be larger than the first amount and/or at least 20 percent larger than the first amount. 
     In some embodiments, the vehicle management system  65  comprises a lighting system  100  having at least one light coupled to an interior of the vehicle  2 . The lighting system  100  can be configured to illuminate at least one of a seat of the vehicle  2  and a majority of the cabin. The vehicle management system  65  can be configured to use the lighting system  100  to illuminate at least one of the seat and the majority of the cabin in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . 
     The light can be a spotlight to illuminate a seat in which the rider that is smoking is sitting. The light can be an LED. The light can be multiple LEDs. 
     In some embodiments, the vehicle management system  65  comprises a speaker  86 . The speaker  86  can be configured to emit audio commands instructing a first rider of the vehicle  2  to cease smoking. The vehicle management system  65  can be configured to cease illuminating the majority of the cabin and/or cease illuminating the seat in response to the smoke detection system  74  no longer detecting the smoke inside the vehicle  2 . 
     In some embodiments, the vehicle management system comprises a lighting system  100  configured to illuminate at least a portion of an interior of the vehicle  2 . The lighting system  100  can comprise at least one light coupled to an interior of the vehicle  2 . The lighting system  100  can be configured to illuminate at least one of a seat of the vehicle  2  and a majority of the cabin (of the vehicle  2 ). The vehicle management system can be configured to use the lighting system  100  to illuminate at least one of the seat and the majority of the cabin in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . 
     In some embodiments, the maintenance system comprises at least one processor  77  and at least one memory  75  having program instructions  76  that when executed by the at least one processor  77  are configured to cause the vehicle management system to illuminate at least one of the seat and the majority of the cabin in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . 
     In some embodiments, the vehicle management system is configured to cease illuminating at least one of the seat and the majority of the cabin in response to the smoke detection system  74  in response to the smoke detection system  74  no longer detecting smoke inside the vehicle  2 , detecting that a concentration of the smoke is less than a predetermined threshold, detecting that a concentration of the smoke is decreasing, and/or detecting that a concentration of the smoke has decreased by at least a predetermined amount and/or ratio. 
     In some embodiments, the smoke detection system  74  is configured to analyze a particle size of the smoke to determine if the particle size is smaller than a predetermined threshold. The vehicle management system can be configured to illuminate at least one of the seat of the vehicle  2  and the majority of the cabin in response to the maintenance system detecting the smoke inside the vehicle  2  and determining that the particle size is smaller than the predetermined threshold. 
     In some embodiments, the vehicle management system comprises at least one of a speaker  86  and a display screen  93 . At least one of the speaker  86  and the display screen  93  can be configured to provide at least one of audio instructions and visual instructions to a first rider inside the vehicle  2 . At least one of the audio instructions and the visual instructions can be configured to instruct the first rider to cease smoking while at least one of the seat and the majority are illuminated by the lighting system  100 . 
     The vehicle management system  65  can cause the vehicle  2  to go to a service area  8  to clean the vehicle  2 . Cleaning the vehicle  2  can help remove the smoke smell. 
     In some embodiments, the vehicle management system  65  is configured to receive a first location of a service area  8  configured to clean the vehicle  2 . The vehicle management system  65  can be configured to drive the vehicle  2  to the service area  8  in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . 
     In some embodiments, the smoke detection system  74  is configured to detect the smoke emitted by a first rider while the vehicle  2  is driving to a drop off location of the first rider. The vehicle management system  65  can comprise a first mode and a second mode. In the first mode, the vehicle management system  65  is configured to make the vehicle  2  available to accept a pick-up request of a second rider. In the second mode, the vehicle management system  65  is configured to make the vehicle  2  unavailable to accept the pick-up request. The vehicle management system  65  can be configured to enter the second mode in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . The vehicle management system  65  can be configured to exit the second mode and enter the first mode in response to at least one of receiving an indication that the vehicle  2  has been cleaned and the vehicle  2  leaving a vehicle cleaning station. 
     In some embodiments, the vehicle management system  65  comprises a ventilation system  84  having a fan  83  to push air in the cabin. The fan  83  can be embedded in a vent channel of the dash or can be located in any other suitable location. The smoke detection system  74  can be configured to analyze a particle size of the smoke to determine if the particle size is smaller than a predetermined threshold. The vehicle management system  65  can be configured to automatically increase a rate at which the ventilation system  84  pushes outside air into the cabin in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . The vehicle management system  65  can be configured to drive the vehicle  2  to a service area  8  configured to clean the vehicle  2  in response to determining that the particle size is smaller than the predetermined threshold. 
     In some embodiments, the vehicle management system  65  comprises a motor  81  configured to roll down a window  82  of the vehicle  2 . The smoke detection system  74  is configured to analyze a particle size of the smoke to determine if the particle size is smaller than a predetermined threshold. The vehicle management system  65  can be configured to use the motor  81  to automatically roll down the window  82  in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . The vehicle management system  65  can be configured to drive the vehicle  2  to a service area  8  configured to clean the vehicle  2  in response to determining that the particle size is smaller than the predetermined threshold. 
     In some embodiments, the vehicle management system  65  comprises at least one of a motor  81  configured to roll down a window  82  of the vehicle  2  and a ventilation system  84  having a fan  83  to push air in the cabin. The smoke detection system  74  can be configured to detect the smoke emitted by a first rider while the vehicle  2  is driving to a drop off location of the first rider. The smoke detection system  74  can be configured to analyze a particle size of the smoke to determine if the particle size is smaller than a predetermined threshold. 
     In some embodiments, in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 , the vehicle management system  65  is configured to at least one of use the motor  81  to automatically roll down the window  82  and increase a rate at which the ventilation system  84  pushes the air into the cabin. 
     In some embodiments, in response to determining that the particle size is larger than the predetermined threshold and after at least one of rolling down the window  82  and increasing the rate (at which the ventilation system  84  pushes the air into the cabin), the vehicle management system  65  is configured to make the vehicle  2  available to pick up a second rider. 
     In some embodiments, in response to determining that the particle size is smaller than the predetermined threshold, the vehicle management system  65  is configured to make the vehicle  2  unavailable to pick up the second rider until after the vehicle management system  65  has driven the vehicle  2  to a service area  8  configured to clean the vehicle  2 . 
     In some embodiments, the vehicle management system  65  comprises a motor  81  configured to roll down a window  82  of the vehicle  2  and a rain sensor  87  configured to detect an indication of rain on the vehicle  2 . The smoke detection system  74  can be configured to analyze a particle size of the smoke to determine if the particle size is smaller than a predetermined threshold. The vehicle management system  65  can be configured to use the motor  81  to automatically roll down the window  82  in response to the smoke detection system  74  detecting the smoke inside the vehicle  2  and/or in response to the rain sensor  87  not detecting the indication of the rain. The vehicle management system  65  can be configured to drive the vehicle  2  to a service area  8  configured to clean the vehicle  2  in response to determining that the particle size is smaller than the predetermined threshold. 
     In some embodiments, the vehicle management system  65  comprises a motor  81  configured to roll down a window  82  of the vehicle  2  and a rain sensor  87  configured to detect an indication of rain on the vehicle  2 . The vehicle management system  65  can be configured to use the motor  81  to automatically roll down the window  82  in response to the smoke detection system  74  detecting the smoke inside the vehicle  2  and in response to the rain sensor  87  not detecting the indication of the rain. 
     A seat belt (also known as a seatbelt or safety belt) is a vehicle safety device designed to secure an occupant of a vehicle against harmful movement that may result during a collision or a sudden stop. 
     Seat belts can dramatically reduce the risk of injury during a crash. Seat belts save many lives every year. In some embodiments, the vehicle management system is configured to take certain actions to encourage a first rider to wear a seat belt. 
     The vehicle can comprise a sensor configured to detect if the rider is “wearing” a seat belt (i.e., if the seat belt is secured around the first rider by a strap and/or a buckle). In some embodiments, the sensor is located in the buckle and includes a contact sensor configured such that the sensor detects if the seat belt is buckled (or if the seat belt is not buckled). 
     In some embodiments, the vehicle management system is configured to reduce a speed of the vehicle in response to the vehicle management system determining (e.g., based on data from the seat belt sensor) that the seat belt is not buckled. Reducing the speed can encourage the rider to buckle her seat belt. 
     In some embodiments, the vehicle management system is configured to intentionally increase a travel time of the vehicle in response to the vehicle management system determining (e.g., based on data from the seat belt sensor) that the seat belt is not buckled. 
     In some embodiments, the vehicle management system is configured to increase the travel time by changing from a first travel route to a destination (chosen by a first rider) to a second travel route to the destination. The vehicle management system can be configured to change from the first travel route to the second travel route to intentionally increase the travel time in response to the vehicle management system determining (e.g., based on data from the seat belt sensor) that the seat belt is not buckled. Increasing the travel time can encourage the rider to buckle her seat belt. 
     In some embodiments, the vehicle is configured to drive a first rider to a destination (that was previously chosen by the first rider). The vehicle management system can be configured to cease driving toward the destination in response to the vehicle management system determining (e.g., based on data from the seat belt sensor) that the seat belt is not buckled. 
     In some embodiments, the vehicle management system comprises a lighting system having at least one light coupled to an interior of the vehicle. The lighting system can be configured to illuminate at least a portion of the interior of the vehicle (e.g., at least one of a seat of the vehicle and a majority of the cabin). The vehicle management system can be configured to use the lighting system to illuminate at least the portion (e.g., the seat and/or the majority of the cabin) in response to the vehicle management system determining (e.g., based on data from the seat belt sensor) that the seat belt is not buckled. 
     In some embodiments, the vehicle management system comprises at least one of a speaker and a display screen. At least one of the speaker and the display screen can be configured to provide at least one of audio instructions and visual instructions to a first rider inside the vehicle. In response to the vehicle management system determining that the seat belt is not buckled (e.g., based on data from the seat belt sensor), at least one of the audio instructions and the visual instructions can be configured to instruct the first rider to buckle her seat belt. 
     In some embodiments, a maintenance system is configured to be used with a self-driving vehicle  2 . A maintenance system can comprise a smoke detection system  74  coupled to the vehicle  2  and configured to detect smoke inside a cabin of the vehicle  2 . A maintenance system can comprise a vehicle management system configured to autonomously drive the vehicle  2 . 
     In some embodiments, the vehicle management system is configured to intentionally increase a travel time of the vehicle  2  in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . Intentionally increasing the travel time can motivate the rider to stop smoking in the vehicle  2 . 
     In some embodiments, the vehicle management system is configured to increase the travel time by changing from a first travel route to a destination (e.g., a destination chosen by a first rider) to a second travel route to the destination. The vehicle management system can be configured to change from the first travel route to the second travel route to intentionally increase the travel time in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . 
     The first travel route can be an optimal travel route determined by Google Maps. Google Maps can estimate that the second travel route would take longer (to arrive at a drop-off location of the rider) than the first travel route. Switching to a travel route that takes longer can encourage the rider to stop smoking (in order to prompt the vehicle  2  to choose an optimal travel route). In some cases, the second travel route includes a stop at a cleaning facility, a police station, and/or a facility that manages the vehicle  2 . 
     In some embodiments, the vehicle management system comprises at least one of a speaker  86  and a display screen  93 . At least one of the speaker  86  and the display screen  93  can be configured to provide at least one of audio instructions and visual instructions to a first rider in the vehicle  2 . At least one of the audio instructions and the visual instructions can be configured to warn the first rider to cease smoking to avoid increasing the travel time. 
     For example, audio instructions can say, “Stop smoking immediately or your travel time will be increased.” Visual instructions can include the following words on the display screen  93 : “You must stop smoking to avoid delaying your travel.” 
     In some embodiments, the vehicle management system comprises at least one of a speaker  86  and a display screen  93 . At least one of the speaker  86  and the display screen  93  is configured to provide at least one of audio instructions and visual instructions to a first rider. At least one of the audio instructions and the visual instructions can be configured to instruct the first rider to cease smoking in order to decrease the travel time. 
     For example, audio instructions can say, “We have delayed your travel due to detecting smoke. Stop the smoke immediately to save time.” Visual instructions can include the following words on the display screen  93 : “Due to detecting smoke in the vehicle, your travel route has been changed. To save time and get back on an optimal travel route to your destination, stop smoking.” 
     In some embodiments, the maintenance system comprises at least one processor  77  and at least one memory  75  having program instructions  76  that when executed by the at least one processor  77  are configured to cause the vehicle management system to increase the travel time of the vehicle  2  in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . 
     In some embodiments, the vehicle management system is configured to reduce a speed of the vehicle  2  in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . 
     In some embodiments, in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 , the vehicle management system is configured to automatically reduce the speed while still enabling the vehicle  2  to continue transporting a first rider toward a destination selected by the first rider. 
     A longer travel time reduces the convenience of travel for the rider, which can be a means to encourage the first rider not to smoke in the vehicle  2 . 
     In some embodiments, the vehicle management system is configured to determine a local speed limit. A camera  111  of the vehicle  2  can take a picture of a speed limit sign. Software can be used to “read” the sign to determine the local speed limit. 
     The local speed limit applies to the road on which the vehicle  2  is located. In some embodiments, the vehicle management system determines the local speed limit by sending a GPS location of the vehicle  2  to a system having a database comprising locations and corresponding speed limits and then receiving the local speed limit from the system. 
     The vehicle management system can be configured to intentionally reduce the speed of the vehicle  2  to a velocity below the local speed limit and above five miles per hour (and/or above ten miles per hour) in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . As a result, the vehicle  2  can continue moving while still encouraging the rider to stop smoking in the vehicle  2 . 
     In some embodiments, the maintenance system comprises at least one processor  77  and at least one memory  75  having program instructions  76  that when executed by the at least one processor  77  are configured to cause the vehicle management system to intentionally reduce the speed of the vehicle  2  to a velocity below a local speed limit and above five miles per hour (and/or above ten miles per hour) in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . 
     In some embodiments, the vehicle management system comprises at least one of a speaker  86  and a display screen  93 . At least one of the speaker  86  and the display screen  93  can be configured to provide at least one of audio instructions and visual instructions to a first rider. At least one of the audio instructions and the visual instructions can be configured to instruct the first rider to cease smoking in order to increase the speed. 
     For example, the audio instructions can say, “We cannot increase the speed until the smoke is gone from inside the vehicle.” The visual instructions can display the following words on the display screen  93 : “We will not increase the speed until the smoke is gone from inside the vehicle.” 
     In some embodiments, the smoke detection system  74  is configured to analyze a particle size of the smoke to determine if the particle size is smaller than a predetermined threshold. The vehicle management system can be configured to reduce the speed in response to the maintenance system detecting the smoke inside the vehicle  2  and determining that the particle size is smaller than the predetermined threshold. 
     In some embodiments, the maintenance system is configured to detect smoke from a rider smoking inside the vehicle  2  and/or is configured to detect smoke from a fire inside the vehicle  2 . If the smoke is from a fire inside the vehicle  2 , the maintenance system can take steps to protect the rider and the vehicle  2 . If the smoke is from a smoking a cigarette or vaping inside the vehicle  2 , the maintenance system can take steps to protect the vehicle  2  (and in some cases to protect riders from the smoke). 
     The maintenance system can, in some cases, differentiate between smoke from fire, smoke from smoking a cigarette, and smoke from vaping based on the particle size of the smoke, based on the concentration of the smoke, based on temperature data (e.g., from infrared sensors and/or thermometers configured to detect temperatures inside the cabin of the vehicle  2 ). A high concentration of smoke can indicate that the smoke is more likely from a fire than from smoking a cigarette. A larger particle size can indicate that the smoke is more likely from vaping than from a cigarette and/or a fire. 
     A vehicle  2  can be configured to drive a first rider to a destination chosen by the first rider. (The destination can be a drop-off location.) The vehicle management system can be configured to cease driving toward the destination in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . 
     In some embodiments, the maintenance system comprises at least one processor  77  and at least one memory  75  having program instructions  76  that when executed by the at least one processor  77  are configured (to cause the vehicle management system) to cause the vehicle  2  to cease driving toward the destination in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . 
       FIG.  9    illustrates a lock  92  configured to impede the door  62  from being opened by a rider of the vehicle  2 . In some embodiments, the vehicle management system uses the lock  92  to unlock the doors  62  to enable the rider to open a door  62  of the vehicle  2 . 
     The vehicle management system can use the lock  92  to unlock the doors  62  to enable the rider to open a door  62  of the vehicle  2  in response to the smoke detection system  74  detecting smoke in the vehicle  2 . The vehicle management system can use the lock  92  to unlock the doors  62  to enable the rider to open a door  62  of the vehicle  2  in response to the maintenance system determining that a concentration of the smoke is greater than a first predetermined threshold. The vehicle management system can use the lock  92  to unlock the doors  62  to enable the rider to open a door  62  of the vehicle  2  in response to the maintenance system determining that an average particle size of the smoke is smaller than a second predetermined threshold. 
     The vehicle management system can cause the vehicle  2  to pull over and then automatically unlock the door  62  (e.g., once the vehicle  2  has stopped moving and/or once the vehicle is moving at less than 5 miles per hour). Program instructions  76  can be configured to cause the vehicle  2  to pull over and then unlock a lock  92  of a door  62  of the vehicle  2 . 
     In some embodiments, in response to the smoke detection system  74  detecting smoke in the vehicle  2  (and/or in response to the maintenance system determining that a concentration of the smoke is greater than a first predetermined threshold and/or in response to the maintenance system determining that an average particle size of the smoke is smaller than a second predetermined threshold), the vehicle management system can cause the vehicle  2  to pull over and then use a motor  63  (illustrated in  FIG.  9   ) to open a door  62  automatically without the rider having to open the door  62 . Program instructions  76  can be configured to cause the vehicle  2  to pull over and then use a motor  63  of the lock  92  to open a door  62  of the vehicle  2 . 
     In some embodiments, the maintenance system comprises at least one processor  77  and at least one memory  75  having program instructions  76  that when executed by the at least one processor  77  are configured to cause the vehicle management system to unlock doors  62  of the vehicle  2  in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . Unlocking the doors  62  can enable riders to exit the vehicle  2  (e.g., after the vehicle  2  has come to a stop). 
     The vehicles  2  comprises at least one door  62  and a door lock  92  configured to impede opening the door  62 . The program instructions  76  can be configured to automatically unlock the door lock in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . 
     The program instructions  76  can be configured to automatically unlock the door lock  62  in response to the smoke detection system  74  detecting the smoke inside the vehicle  2  and also in response to the maintenance system detecting that the vehicle  2  is at least one of stopped and moving at a velocity of less than fifteen miles per hour. 
     Enabling the rider to open the door  62  while the vehicle  2  is moving quickly can be dangerous. Waiting to unlock the door  62  until the vehicle  2  is either stopped or at least only moving slowly can reduce the risk of the rider exiting the vehicle  2  while the vehicle  2  is moving quickly. 
     The program instructions  76  can be configured to automatically unlock the door lock  92  in response to the smoke detection system  74  detecting the smoke inside the vehicle  2  and also in response to at least one of (a) the maintenance system determining that a concentration of the smoke is greater than a first predetermined threshold and (b) the maintenance system determining that a particle size of the smoke is smaller than a second predetermined threshold. 
     Determining, by a portion of the maintenance system, that the concentration of the smoke is greater than the first predetermined threshold can help the maintenance system differentiate between emergencies (e.g., with large amounts of smoke in the cabin of the vehicle  2 ) and non-emergencies (e.g., due to cigarette smoking and/or vaping). Detecting large amounts of smoke can trigger the program instructions  76  to unlock the doors  62 . In some embodiments, detecting small amounts of smoke can trigger the program instructions  76  to unlock the doors  62 . In some embodiments, detecting small amounts of smoke does not trigger the program instructions  76  to unlock the doors  62 . 
     Determining, by a portion of the maintenance system, that a particle size of the smoke is smaller than the second predetermined threshold can help the maintenance system differentiate between emergencies (e.g., with smoke due to a fire in the vehicle  2 ) and non-emergencies (e.g., with smoke that is not due to a fire in the vehicle). A small particle size can be indicative of smoke due to a fire in the vehicle  2 . A large particle size can be indicative of smoke that is not due to a fire in the vehicle  2 . A large particle size can be indicative of vaping in the vehicle  2 . 
     The vehicle  2  can comprise a door  62  and a motor  63  configured to open the door  62 . The program instructions  76  can be configured to cause the motor  63  to open the door  62  in response to the smoke detection system  74  detecting the smoke inside the vehicle  2  and the maintenance system detecting that the vehicle  2  is at least one of stopped and moving at a velocity of less than ten miles per hour. 
     The Tesla Model X (made by Tesla, Inc.) includes a motor configured to open the rear doors. Tesla refers to these doors as “Falcon Wing Doors.” Embodiments can use a Tesla Model X motor and door. 
     Sienna minivans (made by Toyota) include motors configured to open the rear sliding doors. The following patents include door motor information. The entire contents of the following patent are incorporated by reference herein: U.S. Pat. No. 6,081,088; issued Jun. 27, 2000; and entitled Automatic Opening/Closing Apparatus. The entire contents of the following patent are incorporated by reference herein: U.S. Pat. No. 5,986,420; issued Nov. 16, 1999; and entitled Apparatus for Automatically Opening and Closing Pop-Up Door of a Vehicle. 
     The following patent includes door lock information. The entire contents of the following patent are incorporated by reference herein: U.S. Pat. No. 5,769,471; issued Jun. 23, 1998; and entitled Apparatus for Unlocking a Door Lock for a Vehicle. 
     In some embodiments, the smoke detection system  74  is configured to analyze a particle size of the smoke to determine if the particle size is smaller than a predetermined threshold. The vehicle management system can be configured to cease driving toward the destination in response to the maintenance system detecting the smoke inside the vehicle  2  and determining that the particle size is smaller than the predetermined threshold. The vehicle  2  can stop moving, pull over to a parking location alongside the road, and/or stop at a cleaning facility configured to remove the smoke smell from the vehicle  2 . 
     In some embodiments, the vehicle management system is configured to cease driving (stop moving) in response to the maintenance system detecting the smoke inside the vehicle  2  and determining that a concentration of the smoke exceeds a predetermined threshold. The concentration threshold can be configured to be indicative of smoke from a fire rather than smoke from smoking a cigarette or vaping. 
     If a person is located inside the vehicle  2 , then the maintenance system can pull over faster than if a person is not located in the vehicle when the smoke detection system  74  detects the smoke. Pulling over to the side of the road faster can enable the rider to exit the vehicle  2  more quickly but may increase the risk of hitting other vehicles in the process of pulling over. As a result, pulling over slower can be advantageous (to reduce the risk to other vehicles on the road) if a person is not present in the vehicle  2 . 
     In some embodiments, the maintenance system comprises at least one processor  77  and at least one memory  75  having program instructions  76  that when executed by the at least one processor  77  are configured to cause the vehicle  2  to stop moving via (e.g., by) a first stopping mode in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . The program instructions  76  can be configured to cause the vehicle  2  to stop moving via (e.g., by) a second stopping mode in response to the smoke detection system  74  detecting the smoke inside the vehicle  2  and the maintenance system detecting an indication of a person being located inside the vehicle  2 . The second stopping mode can be configured to enable the vehicle  2  to stop more quickly than the first stopping mode. 
     The vehicle guidance system  117  can enable the vehicle  2  to avoid hitting other objects on the road while the vehicle  2  pulls over to stop on the side of the road. 
     A seat of the vehicle  2  can comprise a weight sensor  114  (shown in  FIG.  3   ) configured to sense the weight of a rider sitting on the seat (to enable the maintenance system to detect the rider). A weight greater than a predetermined threshold (e.g., 20 pounds) can be an indication of a person being located in the vehicle  2 . 
     An infrared sensor  115  (shown in  FIG.  3   ) can be used to detect a temperature indicative of a person sitting in a seat of the vehicle  2  (so the maintenance system can determine, based on infrared data) if a person is located in the vehicle  2 . 
     A camera  24   a ,  24   b ,  24   c  can take a picture inside the cabin of the vehicle  2 . Image recognition software can be used to analyze the picture to enable the maintenance system to determine if a person is located inside the vehicle  2 . 
     In some embodiments, the second stopping mode is configured to enable the vehicle  2  to move at a greater speed than the first stopping mode (e.g., to enable the vehicle  2  to arrive at a stopping location more quickly). 
     In some embodiments, the vehicle management system is configured to determine a local speed limit, and the second stopping mode is configured to enable the vehicle  2  to exceed the local speed limit by a greater amount than the first stopping mode. 
     In some embodiments, the second stopping mode is configured to enable the vehicle  2  to accelerate faster than the first stopping mode. 
     In some embodiments, the second stopping mode is configured to enable the vehicle  2  to decelerate faster than the first stopping mode. 
     In some embodiments, the vehicle  2  is configured to drive on a road. The vehicle management system can comprise a vehicle guidance system  117  having at least one of a camera  111 , a radar  118 , and a lidar  119 . 
     The vehicle guidance system  117  can be configured to detect objects located outside the vehicle  2  on the road. Program instructions  76  can be configured to enable the vehicle  2  to come closer to the objects in the second stopping mode than in the first stopping mode. 
     For example, in the second stopping mode, the program instructions  76  can specify a minimum distance to other cars of 10 feet in the second stopping mode and 20 feet in the first stopping mode. As a result, the second stopping mode can enable changing lanes into smaller spaces between cars to enable the vehicle  2  to pull over faster than would be the case in the first stopping mode. 
     In some embodiments, the vehicle management system comprises a vehicle guidance system  117  having at least one of a camera  111 , a radar  118 , and a lidar  119 . The vehicle guidance system  117  can be configured to detect objects located outside the vehicle  2  on the road. The maintenance system can comprise at least one processor  77  and at least one memory  75  having program instructions  76  configured to be executed by the at least one processor  77  and comprising a first mode, a second mode, and a third mode. In the first mode, the program instructions  76  are configured to prompt the vehicle management system to drive the vehicle  2  toward a location (e.g., a destination, a drop-off location, a pick-up location). 
     In some embodiments, the program instructions  76  are configured to exit the first mode and enter the second mode in response to the smoke detection system  74  detecting the smoke inside the vehicle  2  and in response to the maintenance system determining that a person is not located inside the vehicle  2 . In the second mode, the program instructions  76  prompt the vehicle guidance system  117  to implement a first stopping mode. 
     In some embodiments, the program instructions  76  are configured to exit the first mode and enter the third mode in response to the smoke detection system  74  detecting the smoke inside the vehicle  2  and the maintenance system determining that the person is located inside the vehicle  2 . In the third mode, the program instructions  76  prompt the vehicle guidance system  117  to implement a second stopping mode configured to enable the vehicle  2  to come to a stop in less time than the first stopping mode. 
     For example, the second stopping mode may cause the vehicle  2  to come to a stop in fewer seconds than the first stopping mode would cause the vehicle  2  to come to a stop. Fewer seconds can reduce the severity of injury to the rider caused by a fire inside the vehicle  2 . 
     Some embodiments discourage riders from smoking. In some embodiments, the vehicle management system comprises a speaker  86  configured to emit an audio command. The audio command can be configured to instruct the first rider to cease smoking in order to resume driving toward the destination. For example, the audio command can say, “We aren&#39;t driving anywhere until you stop smoking.” 
     In some embodiments, the vehicle management system comprises a display screen  93 . The display screen  93  can be configured to provide visual instructions to the first rider. The visual instructions can be configured to instruct the first rider to cease smoking in order to resume driving toward the destination. For example, the visual instructions can include the following words: “We aren&#39;t driving anywhere until you stop smoking.” 
     In some embodiments, the vehicle management system is configured to resume driving toward the destination in response to at least one of the smoke detection system  74  no longer detecting the smoke and the smoke detection system  74  detecting a decrease in a concentration of the smoke. 
     In some embodiments, the smoke detection system  74  is configured to analyze a particle size of the smoke inside the vehicle  2 . The maintenance system can comprise a speaker  86 , at least one processor  77 , and at least one memory  75 . The memory  75  can comprise program instructions  76  configured to be executed by the at least one processor  77  such that the program instructions  76  are configured to cause the speaker  86  to emit a first audio command in response to the maintenance system determining that the particle size is smaller than a predetermined threshold. For example, the first audio command can say, “Smoke has been detected. We are going to pull over as soon as possible. Please unbuckle and exit the vehicle when safe to do so.” 
     The program instructions  76  can be configured to cause the speaker  86  to emit a second audio command in response to the maintenance system determining that the particle size is larger than the predetermined threshold. The second audio command can be configured to communicate different information than the first audio command to a first rider inside the vehicle  2 . For example, the second audio command can say, “Vaping has been detected. Your account has been fined twenty dollars. Please stop vaping immediately to avoid additional fines.” 
     In some embodiments, the vehicle  2  is configured to drive a first rider to a destination, and the maintenance system comprises at least one processor  77  and at least one memory  75 . The memory  75  can comprise program instructions  76  configured to be executed by the at least one processor  77 . 
     In some embodiments, program instructions  76  comprise a first mode and a second mode. In the first mode, the maintenance system can make the vehicle  2  available to accept a pick-up request of a second rider. In the second mode, the maintenance system can make the vehicle  2  unavailable to accept the pick-up request. The maintenance system can be configured to enter the second mode in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . The maintenance system can be configured to exit the second mode and enter the first mode in response to the smoke detection system  74  no longer detecting the smoke inside the vehicle  2 , the maintenance system detecting that a concentration of the smoke is less than a predetermined threshold, the maintenance system receiving a communication in response to the vehicle  2  having been cleaned, and/or the maintenance system receiving an indication (such as GPS data) indicative of the vehicle  2  having left a cleaning facility. 
     Self-driving vehicles can include cars, vans, trucks, buses, scooters, motorcycles, helicopters, quadcopters, flying machines, air taxis, planes, and any motorized vehicle configured to transport a person. 
     In some embodiments, the vehicle  2  is configured to drive on a road. The vehicle management system can comprise a vehicle guidance system  117 . The vehicle guidance system  117  can comprise radar  118 , lidar  119 , ultrasonic sensors, cameras  111 , and any other sensing devices configured to enable the vehicle  2  to detect objects. 
     The entire contents of the following application are incorporated by reference herein: U.S. patent application Ser. No. 16/205,013; filed Nov. 29, 2018; and entitled SELF-DRIVING VEHICLE SYSTEMS AND METHODS. 
     The vehicles  2  described herein can include any of the features of the vehicles described in U.S. patent application Ser. No. 16/205,013. 
     The entire contents of the following application are incorporated by reference herein: U.S. patent application Ser. No. 16/134,190; filed Sep. 18, 2018; and entitled SELF-DRIVING VEHICLE SYSTEMS AND METHODS. 
     The vehicles  2  described herein can include any of the features of the vehicles described in U.S. patent application Ser. No. 16/134,190. 
     Some embodiments can be used with self-driving vehicles. Embodiments, however, are not limited to self-driving vehicles and can be used with non-self-driving vehicles. 
     As used herein, “location” is used broadly and is not limited to a street address. A location can be a Global Positioning System (“GPS”) location and can be any other location indicator. A location can be an outdoor location. A location can be an indoor location (e.g., a location inside a large shopping center, an apartment complex or other building). 
     Some embodiments use iBeacon hardware to enable tracking remote computing devices indoors. iBeacon is a protocol developed by Apple Inc. Several embodiments use radio transceivers (such as Bluetooth transceivers) to enable tracking remote computing devices indoors. 
     Some embodiments use Global Positioning System (“GPS”) hardware to determine an outdoor location of a remote computing device and/or of a vehicle. GPS can include the system of satellites put into orbit and maintained by the U.S. Department of Defense, Russia&#39;s GLONASS satellite system, assisted GPS systems, and/or any satellite system used to provide location data. 
     In some embodiments, each system comprises at least one processor and a memory comprising program instructions that when executed by the at least one processor cause the system to perform any of the steps described herein and/or incorporated by reference. 
     A self-driving vehicle  2  can include a vehicle guidance system  117  configured to detect objects (e.g., cars, pedestrians, other vehicles, buildings, fire hydrants, trees, lane markers, guard rails, roadway barriers, sidewalks, roadway signs, traffic lights) located around the self-driving vehicle  2 . Various sensors of the vehicle guidance system  117  can sense objects even closer than an inch away (e.g., by using ultrasonic sensors) and even farther away than 100 yards (e.g., using long-range radar). 
       FIG.  12    illustrates a perspective view of the top side, the front side and the passenger side of the vehicle guidance system  117  coupled to the vehicle  2 .  FIG.  13    illustrates a perspective view of the top side, the backside side and the driver side of the vehicle guidance system  117  coupled to the vehicle  2 . 
     The vehicle guidance system  117  can comprise radar  118 , lidar  119 , ultrasonic sensors, cameras  111 , and any other sensing devices configured to enable the vehicle  2  to detect objects. 
     The self-driving vehicle  2  can comprise a vehicle guidance system  117  mounted to the roof of the self-driving vehicle  2 . In some embodiments, however, the components of the vehicle guidance system  117  are mounted on different areas of the self-driving vehicle  2 . For example, the ultrasonic sensors can be mounted on the bumpers of the self-driving vehicle  2 . The short range of the ultrasonic sensors can make bumper mounting helpful (because the bumper is often closer to the objects being sensed). The cameras  111  can be mounted just behind the windshield (e.g., in the rearview mirror) and just behind other windows. The radars  118  can be mounted near each of the four corners of the self-driving vehicle  2 . In the illustrated embodiment, however, the vehicle guidance system  117  can be contained in one assembly to simplify the integration of the vehicle guidance system  117  into a vehicle. 
     The vehicle guidance system  117  can use cameras  111  mounted around a perimeter (e.g., around a perimeter of the vehicle  2  or around a perimeter of a housing of the vehicle guidance system  117 ). As illustrated in  FIGS.  12  and  13   , cameras  111  face forward, backward, left, and right to provide (collectively) a 360 degree view around the vehicle  2 . The cameras  111  can be high-resolution cameras covered by a glass window to protect each cameras  111  from water and dirt. 
     Cameras  111  can be configured to see lane markers on a road. Using cameras  111  to see painted lane markers can be helpful (because painted lane markers sometimes lack enough three-dimensional nature to be detected by some other sensors). In addition, cameras  111  can see color differences (e.g., the difference between the color of the asphalt and the color of yellow or white paint of a lane marker). Cameras  111  can see the color of traffic lights (e.g., red, yellow, green). 
     Cameras  111  sometimes have trouble seeing in situations where the human eye would have trouble seeing (e.g., in fog or rain). 
     Radars  118  can be very helpful in fog and rain. An object that is not detected by cameras  111  (e.g., due to fog or rain) can be detected by radar  118 . Radars  118  can detect the speed of other vehicles and the distance to other vehicles. Radars  118  can also detect objects that are far away. 
     Radar is an object-detection system that uses radio waves to determine the range, angle, or velocity of objects. A radar can comprise a transmitter producing electromagnetic waves in the radio or microwave domain, a transmitting antenna, a receiving antenna (which can be the same antenna as the transmitting antenna), a receiver, and/or a processor to determine properties of the objects detected by the radar. 
     Lidar uses light to detect objects. A lidar  119  can be located on the top portion of the vehicle guidance system  117  to provide a 360 degree view of the area around the self-driving vehicle  2 . The lidar  119  can tell the difference between an actual person and a billboard that includes a picture of a person (due to the three-dimensional nature of the actual person and the two dimensional nature of the picture of a person). 
     The lidar  119  can accurately sense the three-dimensional nature of the world around the self-driving vehicle  2 . The lidar  119  can also measure the distance to objects. Measuring distance can enable the self-driving vehicle  2  to know, for example, if an approaching car is 5 meters away (so there is not enough time to turn in front of the car) or 25 meters away (so there may be enough time to turn in front of the car). 
     In some embodiments, the lidar  119  is a Velodyne VLS-128 made by Velodyne LiDAR, Inc. having an office in San Jose, Calif. The Velodyne VLS-128 can provide real-time, three-dimensional data with up to 0.1 degree vertical and horizontal resolution, a range of up to 300 meters, and a 360-degree surround view. The VLS-128 can provide the range, resolution and accuracy required by some of the most advanced autonomous vehicle programs in the world. 
     Many types of lidars can be used. Some embodiments use “incoherent” or direct energy detection (which principally measures amplitude changes of the reflected light). Some embodiments use coherent detection (which in some cases can be well suited for measuring Doppler shifts, or changes in phase of the reflected light). Coherent systems can use optical heterodyne detection. 
     Lidar can use pulse models. Some lidar embodiments use micropulse or high energy. Micropulse systems can use intermittent bursts of energy. Some lidar embodiments use high-power systems. 
     Lidar can comprise lasers. Some embodiments include solid-state lasers. Some embodiments include flash lidar. Some embodiments include electromechanical lidar. Some embodiments include phased arrays to illuminate any direction by using a microscopic array of individual antennas. Some embodiments include mirrors (e.g., micro electromechanical mirrors). Some embodiments include dual oscillating plane mirrors, a polygon mirror and/or a scanner (e.g., a dual-axis scanner). 
     Lidar embodiments can include photodetector and receiver electronics. Any suitable type of photodetector can be used. Some embodiments include solid-state photodetectors (e.g., silicon avalanche photodiodes) and/or photomultipliers. 
     The motion of the vehicle  2  can be compensated for to accurately determine the location, speed, and direction of objects (such as other vehicles) located outside the vehicle  2 . For example, if a first vehicle  2  is heading west at 35 miles per hour and a second vehicle is heading east at an unknown speed, a vehicle guidance system  117   a  of the first vehicle  2  can remove the contribution of the 35 miles per hour when determining the speed of the second vehicle. 
     In some embodiments, motion of the vehicle  2  is compensated for by using position and navigation systems to determine the absolute position, speed, and orientation of the lidar, camera, radar, or other object sensing system. A Global Positioning System (“GPS”) receiver and/or an Inertial Measurement Unit (“IMU”) can be used to determine the absolute position and orientation of the object sensing system. 
     Lidar can use active sensors that supply their own illumination source. The energy can hit objects. The reflected energy can be detected and measured by sensors. Distance to the object can be determined by recording the time between transmitted and backscattered pulses and by using the speed of light to calculate the distance traveled. Scanning can be used to create a three-dimensional image or map of the area around the vehicle  2 . 
     Embodiments can use a short-range lidar to give the self-driving vehicle  2  a surround view near the self-driving vehicle  2  (to see objects close to the self-driving vehicle  2 ) and can use a long-range lidar configured to not only detect objects located far from the self-driving vehicle  2 , but also to enable zooming into objects that are over 200 meters away. The long-range lidar can be very helpful at high-speed highway situations. 
     Lidar uses light to detect a distance to an object, a direction to the object, and/or a location of an object. Lidar can use pulsed laser light emitted by a laser. 
     The light can reflect off objects around the vehicle  2 . These reflections can be detected by a sensor of the lidar. Measuring how long the light takes to return to the sensor and measuring the wavelengths of the reflected light can enable making a three-dimensional model of the object being sensed and of the entire area around the vehicle  2 . 
     The self-driving vehicle  2  can include a vehicle navigation system, a communication system that has a transmitter and a receiver, a computer system that has a processor, a memory that has program instructions and map information, a traffic monitor, and a drive-by-wire system. In some embodiments, at least some of these items are part of the vehicle guidance system  117 . 
     A vehicle navigation system can be configured to enable the vehicle  2  to follow a driving route. The vehicle navigation system can direct the vehicle toward a pick-up location, a drop-off location, and/or another location. 
     A communication system can be configured to communicate with a vehicle management system. The communication system can be configured to communicate with a remote computing device of a rider. The communication system can use an antenna to communicate with other vehicles and other devices via intermediary communication systems. 
     Intermediary communication systems can comprise wireless networks, Wi-Fi routers, Bluetooth systems, cellular networks, telephone networks, Internet systems, servers, cloud computing, remotely located computers, satellite systems, communication systems, and any other suitable means of enabling communication between the various components of embodiments described herein and/or incorporated by reference. 
     The vehicle  2  can comprise a drive-by-wire system. The drive-by-wire system can be a computer-regulated system for controlling the engine, accelerating, braking, steering, signaling, handling, suspension, and/or other functions related to autonomously driving the vehicle  2 . 
     Receiving radio communications (with position data) from three or more GPS satellites can provide data to enable each vehicle and each remote computing device to calculate its own position. 
     Each device can receive radio signals broadcasted from GPS satellites. Then, the device can calculate how far it is away from the broadcasting satellite by determining how long the radio signal (traveling at lightspeed) took to arrive at the device. Trilateration (based on data from at least three GPS satellites) enables the device to know where it is located. The device can then send its location to the vehicle management system. A location tracking system can receive the location data from the vehicle management system, from the device, and/or from any other system. 
     Communicative coupling may be via continuous communications or intermittent communications. Intermittent communications can be via periodic communications (e.g., every 1 second, every 60 seconds, every 10 minutes). As used herein, “periodically” does not imply that every period has the same duration. In some embodiments, the communicative coupling is via intermediary communication systems  15 . 
     A remote computing device can be a smartphone, a tablet computer, a laptop computer, a desktop computer, a server, augmented reality glasses, an implanted computer, and/or any type of computer. A rider can bring her remote computing device into the self-driving vehicle, use her remote computing device in the self-driving vehicle, and leave the self-driving vehicle with her remote computing device. In some embodiments, the rider requests a ride at her home with a remote computing device, but then leaves the remote computing device at home when she goes to get a ride from the self-driving vehicle. 
     In some embodiments, a remote computing device comprises an accelerometer, a barometer (which can include an altimeter), a gyroscope, a WiFi tracker, a compass, a location tracking system, a memory, a computer system having a processor, a database and/or a communication system. The communication system can include a transmitter, a receiver, and/or an antenna. The remote computing device can comprise a display screen configured to display images to a rider. The remote computing device can comprise a speaker configured to emit sounds to the rider. The remote computing device can comprise a microphone configured to record sounds from the rider. 
     A maintenance system can be configured to be used with one or more self-driving vehicles. A maintenance system can comprise a smoke detection system  74  coupled to the vehicle  2  and configured to detect smoke inside a cabin of the vehicle  2 ; and a vehicle management system  65  configured to autonomously drive the vehicle  2 . 
     The vehicle management system  65  can comprise a motor  81  configured to open a window  82  of the vehicle  2 . The vehicle management system  65  can also comprise a ventilation system  84  having a fan  83  to configured circulate air in the cabin. Many different types of fans can be used. For example, Porsche vehicles, Acura vehicles, Ford vehicles, Toyota vehicles, and many other vehicles use fans to circulate air inside vehicles. 
     Fans can include revolving blades or fins configured to push air. Some embodiments use axial fans. Some embodiments use centrifugal fans. Some embodiments use cross flow fans. Tubular fans, tangential fans, and squirrel cage fans can be used with the embodiments described herein and/or incorporated by reference. 
     A maintenance system can comprise a computer system  7  comprising at least one processor  77  and a memory  75  having program instructions  76  that when executed by the at least one processor  77  are configured to cause the motor  81  to automatically open the window  82  in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . The program instructions  76  can be configured to increase a rotational speed of the fan  83  in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . 
     In some embodiments, a vehicle management system  65  comprises a motor  81  configured to open a window  82  of the vehicle  2 . The vehicle management system  65  can comprise program instructions  76  configured to cause the motor  81  to automatically open the window  82  in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . 
     Many different types of motors can be used to open and close windows  82 . AutoZone sells a wide selection of window  82  lift motors. Dorman Products has an office in Colmar, Pennsylvania has a range of window  82  lift motors. These motors can be configured to “roll up” and “roll down” a window  82  (e.g., a door window) of a car. 
     Air, especially in urban areas, generally has low levels of smoke even when a person is not smoking in the area. Thus, it is advantageous for some of the embodiments described herein to only react if the concentration of smoke is above a predetermined threshold. 
     Program instructions  76  can be configured to cause the motor  81  to automatically open the window  82  in response to the smoke detection system  74  detecting a concentration of the smoke greater than a predetermined threshold. 
     In response to the smoke detection system  74  detecting the smoke inside the vehicle  2 , the program instructions  76  can prevent a first rider from closing the window  82  by at least one of disabling the motor  81 , disabling a switch configured to move the window  82 , disabling a system configured to close the window  82 , and locking the window  82  in an open position. 
     The system configured to close the window  82  can include a window  82  lock, a switch (that when touched or activated opens or closes the window  82 ), a motor  81  configured to open or close the window  82 , other electrical components used to operate the window  82 , a power supply configured to operate the motor  81  or the other electrical components used to operate the window  82 , guides that direct the window  82  as the window  82  “rolls” or moves down (or up), electrical connections configured to control the flow of electricity to components related to operating the window  82 . 
     The system configured to close the window  82  can include any of the components, parts, and systems used to open and close windows in vehicles made by Tesla, Toyota, Ford, Honda, GMC, BMW, and Nissan. 
     After causing the motor  81  to open the window  82 , the program instructions  76  can cause the motor  81  to automatically close the window  82  in response to at least one of the smoke detection system  74  no longer detecting the smoke inside the vehicle  2  and the smoke detection system  74  detecting a concentration of the smoke less than a predetermined threshold. 
     Accurately detecting if a rider is smoking in the vehicle  2  can be difficult if the windows are open. Open windows can bring in so much outside air that detecting the smoke can be difficult. If the system suspects that the rider may be smoking (e.g., due to detecting very low levels of smoke), the system can roll up the windows to enable the system to more accurately determine if the rider is smoking in the vehicle  2 . Then, if the system determines that the rider is smoking, the system can roll down the windows to reduce smoke damage to the vehicle  2 . 
     In some embodiments, the vehicle management system  65  comprises a motor  81  configured to close a window  82  of the vehicle  2 . The vehicle management system  65  can comprise program instructions  76  configured to cause the motor  81  to automatically close the window  82  in response to the smoke detection system  74  detecting a first concentration of the smoke greater than a first predetermined threshold to enable the smoke detection system  74  to detect a second concentration of the smoke above a second predetermined threshold with the window  82  closed. The second predetermined threshold can be greater than the first predetermined threshold. 
     The maintenance system can comprise a communication system. In response to detecting the second concentration of the smoke above the second predetermined threshold, the program instructions  76  can cause the communication system to send a first wireless communication to a remote computing device. The first wireless communication can be configured to notify the remote computing device regarding the smoke. 
     After the program instructions  76  cause the motor  81  to automatically close the window  82  in response to the smoke detection system  74  detecting the first concentration of the smoke above the first predetermined threshold, the program instructions  76  can cause the motor  81  to automatically open the window  82  in response to detecting the second concentration of the smoke above the second predetermined threshold. 
     Accurately detecting if a rider is smoking in the vehicle  2  can be difficult if the ventilation system  84  is quickly blowing a high volume of air into the cabin of the vehicle  2 . The ventilation system  84  can bring in so much outside air and/or filtered air that detecting the smoke can be difficult. If the system suspects that the rider may be smoking (e.g., due to detecting very low levels of smoke), the system can reduce a rate at which the ventilation system  84  blows air into the cabin to enable the system to more accurately determine if the rider is smoking in the vehicle  2 . (In some embodiments, the system stops the fan.) Then, if the system determines that the rider is smoking, the system can increase the rate at which the ventilation system  84  blows air into the cabin to reduce smoke damage to the vehicle  2 . 
     The vehicle management system  65  can comprise a ventilation system  84  having a fan  83  to configured circulate air in the cabin. The vehicle management system  65  can comprise program instructions  76  configured to reduce a rotational speed of the fan  83  in response to the smoke detection system  74  detecting a first concentration of the smoke above a first predetermined threshold to enable the smoke detection system  74  to detect a second concentration of the smoke above a second predetermined threshold after the rotational speed is reduced. The second predetermined threshold can be greater than the first predetermined threshold. 
     The maintenance system can comprise a communication system. In response to detecting the second concentration of the smoke above the second predetermined threshold, the program instructions  76  can cause the communication system to send a first wireless communication to a remote computing device. The first wireless communication can be configured to notify the remote computing device regarding the smoke in the vehicle  2 . 
     After the program instructions  76  reduce the rotational speed of the fan  83  in response to the smoke detection system  74  detecting the first concentration of the smoke above the first predetermined threshold, the program instructions  76  can increase the rotational speed of the fan  83  in response to detecting the second concentration of the smoke above the second predetermined threshold. 
     The vehicle management system  65  can comprise a ventilation system  84  having a fan  83  configured to circulate air in the cabin. The vehicle management system  65  comprises program instructions  76  configured to increase a rotational speed of the fan  83  in response to the smoke detection system  74  detecting the smoke inside the vehicle  2 . 
     The program instructions  76  can be configured to increase the rotational speed of the fan  83  in response to the smoke detection system  74  detecting a concentration of the smoke greater than a predetermined threshold. 
     After increasing the rotational speed of the fan  83 , the program instructions  76  can decrease the rotational speed of the fan  83  in response to at least one of the smoke detection system  74  no longer detecting the smoke inside the vehicle  2  and the smoke detection system  74  detecting a concentration of the smoke less than a predetermined threshold. 
     The vehicle management system  65  can comprise a ventilation system  84  having a fan  83  to configured circulate air in the cabin. The smoke detection system  74  can be configured to analyze a particle size of the smoke to determine if the particle size is smaller than a predetermined threshold. The vehicle management system  65  can comprise program instructions  76  configured to increase a rotational speed of the fan  83  in response to the smoke detection system  74  detecting the smoke inside the vehicle  2  and determining that the particle size is less than the predetermined threshold. The smoke detection system  74  can comprise at least one optical smoke detector configured to analyze the particle size of the smoke. 
     Carbon monoxide can be deadly. Unfortunately, carbon monoxide is typically impossible for humans to detect on their own. Sometimes, vehicle exhaust systems have leaks that allow carbon monoxide (e.g., from the combustion of the engine) to enter the cabin of the vehicle  2 . Carbon monoxide in the cabin can make riders sick and can even be fatal. In some embodiments, the camera device  10  comprises a carbon monoxide detector having a sensor configured to detect carbon monoxide. Holes  34  enable the carbon monoxide to enter the camera device  10  to enable the carbon monoxide detector to detect the carbon monoxide. 
     The maintenance system can comprise a motor  81  configured to open a window  82  of the vehicle  2 ; a carbon monoxide detector; and/or program instructions  76  configured to cause the motor  81  to automatically open the window  82  of the vehicle  2  in response to the carbon monoxide detector detecting a first concentration of carbon monoxide greater than a first predetermined threshold. Opening the window  82  can allow fresh air into the cabin to reduce the concentration of carbon monoxide. 
     The maintenance system can comprise a ventilation system  84  having a fan  83  to configured circulate air in the cabin. The program instructions  76  can be configured to increase a rotational speed of the fan  83  in response to the carbon monoxide detector detecting a second concentration of the carbon monoxide greater than a second predetermined threshold. Increasing the rotational speed can bring fresh air into the cabin of the vehicle  2  to reduce the concentration of carbon monoxide. 
     In addition to detecting smoke within the cabin of the vehicle  2  and the other features disclosed heretofore, the system may also be arranged and configured to detect whether a temperature inside the cabin of the vehicle  2  has reached a predetermined temperature threshold thereby indicating the presence of a dangerous situation. Accordingly,  FIG.  14    illustrates a diagrammatic view of a temperature detection system  110 . It should be appreciated that the temperature detection system  110  may be a component within a safety detection system configured to be used with a self-driving vehicle  2 . 
       FIG.  14    includes various broken line circles  120 ,  122 ,  124  intended to show different locations that the temperature detection system may be located on the vehicle  2 . Location  120  includes any location within the cabin of the vehicle  2 . Location  122  includes any location within the motor compartment of the vehicle  2 , such as under the hood near the engine. Furthermore, location  124  includes a cargo compartment of the vehicle  2 , such as inside the trunk. Generally, the temperature detection system  110  is intended to monitor the temperature of any location of the vehicle  2 . 
     In this regard, the safety detection system may include the temperature detection system  110  coupled to the vehicle  2  and configured to detect whether a temperature inside at least one of a cabin  120  of the vehicle  2 , a motor compartment  122  of the vehicle  2 , and a cargo compartment  124  of the vehicle  2  exceeds a predetermined threshold. The system may also include a vehicle management system configured to autonomously drive the vehicle  2 . 
     In many embodiments, the vehicle management system is configured to reduce a speed of the vehicle in response to the temperature detection system detecting that the temperature exceeds the predetermined threshold. In some embodiments, the predetermined threshold is 100° F. It should be appreciated that the predetermined threshold may be any temperature, such as 150° F., 200° F., 250° F., 300° F., 350° F. 
     The vehicle management system may include at least one of a speaker  86  and a display screen  93 . The at least one of the speaker  86  and the display screen  93  may be configured to provide at least one of audio instructions and visual instructions to a rider. Furthermore, the at least one of the audio instructions and visual instructions comprise information related to the temperature. At least one of the audio instructions and visual instructions may be configured to alert the rider regarding at least one of the smoke, the door  130  being unlocked, the reduced speed of the vehicle  2 , the window  137  being at least partially open, the seat belt  153  being unbuckled, emergency personnel being notified, the fire extinguisher  180  being activated, and the like. 
     In some embodiments, the system comprises at least one processor  77  and at least one memory  75  having program instructions  76  that when executed by the at least one processor  77  are configured to cause the vehicle  2  to reduce a speed of the vehicle  2  in response to the temperature detection system  110  detecting that the temperature exceeds the predetermined threshold. 
     In many embodiments, the vehicle  2  comprises a door  62  and a door lock  92  configured to impede opening the door  62 , and the program instructions  76  are configured to automatically unlock the door lock  92  in response to the temperature detection system detecting that the temperature exceeds the predetermined threshold. Furthermore, the program instructions  76  may be configured to automatically unlock the door lock  92  in response to the temperature detection system  110  detecting the temperature exceeds the predetermined threshold and the safety detection system detecting that the vehicle  2  is at least one of stopped and moving at a velocity of less than a predetermined velocity, such as fifteen miles per hour. In some embodiments, the vehicle  2  comprises a door  62  and a motor  63  configured to open the door  62 . In such embodiments, the program instructions  76  may be configured to cause the motor  63  to open the door  62  in response to the temperature detection system  110  detecting that the temperature exceeds the predetermined threshold and the safety detection system detecting that the vehicle  2  is at least one of stopped and moving at a predetermined velocity, such as less than ten miles per hour. 
     In some embodiments, the program instructions  76  are configured to automatically unlock the door lock  92  in response to the temperature detection system  110  detecting the temperature exceeds the predetermined threshold and in response to at least one of the safety detection system determining that the temperature exceeds a second predetermined threshold that is greater than the predetermined threshold. 
     In some embodiments, the program instructions are configured to cause the vehicle to stop moving via a first stopping mode in response to the temperature detection system detecting the temperature exceeds the predetermined threshold. Additionally, in some embodiments, the program instructions are configured to cause the vehicle to stop moving via a second stopping mode in response to the temperature detection system detecting the temperature exceeds the predetermined threshold and the safety detection system detecting an indication of a person being located inside the vehicle, and the second stopping mode is configured to enable the vehicle to stop more quickly than the first stopping mode. 
     In some embodiments, the second stopping mode is configured to enable the vehicle  2  to move at a greater speed than the first stopping mode. Furthermore, in some embodiments, the vehicle management system is configured to determine a local speed limit, and the second stopping mode is configured to enable the vehicle  2  to exceed the local speed limit by a greater amount than the first stopping mode. In some embodiments, the second stopping mode is configured to enable the vehicle  2  to accelerate faster than the first stopping mode. In some embodiments, the second stopping mode is configured to enable the vehicle  2  to decelerate faster than the first stopping mode. 
     In many embodiments, the vehicle management system comprises a vehicle guidance system having at least one of a camera, a radar, and a lidar. In many embodiments, the vehicle guidance system is configured to detect objects located outside the vehicle on the road, and the program instructions  76  are configured to enable the vehicle to come closer to the objects in the second stopping mode than in the first stopping mode. 
     With continued reference to  FIG.  14   , a remote computing device  12   c  of a manager  3  of the vehicle  2  can receive wireless communications from the vehicle  2  (in some cases via intermediary communication system  5 ) in response to the vehicle  2  detecting a temperature that exceeds a predetermined threshold. 
     The temperature detection system  110  can include a variety of devices to detect temperature. In some embodiments, the temperature detection system  110  comprises at least one of an image analysis system  70 , an infrared camera  10 , thermocouple  116 , resistance temperature detector (RTD)  121 , thermistor  123 , integrated circuit  125 , pyrometer  126 , and thermometer  128 . 
     Devices such as the thermocouple  116 , resistance temperature detector (RTD)  121 , thermistor  123 , integrated circuit  125 , pyrometer  126 , and thermometer  128  may be configured to detect air and/or a surface temperature in the various locations  120 ,  122 ,  124  of the vehicle  2 . The infrared camera  10  may be configured to detect temperatures within the vehicle  2  by inferring temperature from a portion of the thermal radiation sometimes called black-body radiation emitted by the object being measured. In this regard, the infrared camera  10  may be arranged and configured to monitor specific objects or targets within the vehicle  2 . Additionally, the infrared camera  10  may be arranged and configured to monitor general locations within locations  120 ,  122 ,  124 . 
     In some situations, the temperature may be less than the predetermined threshold but the temperature of an area of the vehicle  2  or a specific object located within the vehicle  2  may be increasing at a rapid rate. As such, to detect these dangerous situations, the temperature detection system  110  (via an infrared camera) may be configured to determine that the temperature is increasing at a rate that exceeds a predetermined rate. For example, the temperature of the cargo area  124  of the vehicle  2  may be well below the predetermined threshold, but a laptop located in the cargo area  124  may be increasing at a rapid rate, such as 20° F. per minute. Accordingly, the temperature detection system  110  may be configured to determine increasing temperature rates of an entire area, such as the cargo area  124  of the vehicle  2 , and/or an individual object, such as the laptop in the cargo area  124 . Various preventative measures can be taken, such as reducing the speed of the vehicle  2  so that the riders can exit safely. 
     A vehicle fire is an emergency in which seconds count. Each second saved until the rider exits the vehicle can significantly reduce the severity of injuries due to the fire. In fact, mere seconds can mean the difference between life and death. 
     Vehicle fires cause some riders to panic. In this panicked state of mind, some riders forget to unbuckle their seat belt, cannot see how to unbuckle their seat belt due to smoke, fail to look for the door unlocking button, fail to find the door unlocking button due to smoke or lack of clear mental processing, fail to look for the door opening handle, and/or even fail to find the door opening handle. Some embodiments reduce fire-related injuries and save lives by enabling riders to exit vehicles more quickly. 
       FIG.  15    illustrates a perspective view of a door  130  of the vehicle  2 . Some portions of the door  130  are hidden to focus attention on the features shown in  FIG.  15   . As indicated by the closed state of the hinges  138  and a retracted state of a rod  149  of the door actuator  135 , the door  130  is in a closed state in  FIG.  15   . 
       FIG.  16    illustrates a perspective view of an open state of the door  130  of the vehicle  2 . Some portions of the door  130  are hidden to focus attention on the features shown in  FIG.  16   . As indicated by the open state of the hinges  138  and an extended state of the rod  149  of the door actuator  135 , the door  130  is in an open state in  FIG.  16   . 
     The rod  149  can retract into an outer housing of the door actuator  135  (which can be a linear actuator) to pull the door  130  closed. The rod  149  can extend out of the outer housing of the door actuator  135  to push the door  130  open. An anchor  150  couples a distal end of the rod  149  to a frame of the vehicle  2 . 
     The vehicle  2  can comprise power door locks. A button  142  can be configured to lock and unlock the door  130 . The button  142  can mechanically and/or electrically interact with the door lock  132 . Pressing the button  142  can send electrical power to a door lock actuator  139  that is configured to unlock the door  130  by placing the door lock  132  in an unlocked state. 
     Referring now primarily to  FIGS.  9 ,  15 , and  16   , the computer system  7  can control the locked and unlocked states of the door lock  132 . For example, program instructions  76  can be configured to lock or unlock the door in response to a safety system detecting various items. 
     A door lock actuator  139  can place the door lock  132  in a locked state (e.g., when a rod  145  of the door lock actuator  139  is in a first position). A door lock actuator  139  can place the door lock  132  in an unlocked state (e.g., when a rod  145  of the door lock actuator  139  is in a second position). 
     The rod  145  can extend out of an outer housing of the door lock actuator  139  and can retract into the outer housing of the door lock actuator  139  to place the door lock  132  in a locked state or in an unlocked state. The door  130  can comprise a door latch  147 . When the door latch  147  is engaged with an anchor coupled to a frame of the vehicle  2 , the door latch  147  holds the door  130  in a closed state. Moving the door latch  147  to disengage the door latch  147  from the anchor coupled to the frame enables the door  130  to open. 
     When the door lock  132  is in a locked state, moving the door handle  146  does not move the door latch  147 . When the door lock  132  is in an unlocked state, moving the door handle  146  moves the door latch  147  to enable opening the door  130 . The door latch  147  can be moved by the door handle  146  or by a door latch actuator  148  that is part of the door lock  132  and/or part of the door latch  147 . 
     The computer system  7  can control the movement of the door lock actuator  139 , the door latch actuator  148 , and the door actuator  135 . Program instructions  76  can be configured to cause movement of the door lock actuator  139 , the door latch actuator  148 , and the door actuator  135 . 
     Embodiments can use many different types of actuators (e.g., for the door lock actuator  139 , the door latch actuator  148 , and the door actuator  135 ). Some embodiments use electric linear actuators. Actuators can be electric, hydraulic, pneumatic, twisted and coiled polymer (TCP), supercoiled polymer (SCP), thermal, magnetic, and/or mechanical. Actuators can comprise electric motors, comb drives, electroactive polymers, hydraulic cylinders, piezoelectric components, pneumatic components, screw jacks, servomechanism, servomotors, solenoids, stepper motors, shape memory alloys, and/or thermally active components. 
       FIG.  17    illustrates a perspective view of a door  130   a . The door  130  illustrated in  FIGS.  15  and  16    can include all of the components described in the context of the door  130   a  in  FIG.  17   . Many components of the door  130   a  are hidden to more clearly show particular components in  FIG.  17   . 
     Referring now primarily to  FIGS.  9  and  17   , the door  130   a  can comprise a window regulator  152  configured to open and close a window  137  of the door  130   a . A motor  136  can cause a cable and pulley system of the window regulator  152  to move the window up and down. 
     The computer system  7  can control the open and closed states of the window  137  by causing the motor  136  of the window regulator  152  to move the window  137  up and down. The motor  136  can be an electric motor that is electronically controlled by the computer system  7 . Program instructions  76  can be configured to open and close the window  137  in response to a safety system detecting various items. 
     Additional vehicle details are described in U.S. Pat. Nos. 6,530,251; 5,386,5713; 6,328,353; and 4,929,007. The entire contents of U.S. Pat. Nos. 6,530,251; 5,386,713; 6,328,353; and 4,929,007 are incorporated by reference herein. 
     In many embodiments, a safety system includes a self-driving vehicle  2  and a vehicle management system configured to autonomously drive the self-driving vehicle. The safety system may also include a smoke detection system  74  coupled to the self-driving vehicle  2  and configured to detect smoke inside a cabin of the self-driving vehicle  2 . 
     With reference to  FIG.  15   , the self-driving vehicle  2  may include a door  130  and a door lock  132  configured to impede opening the door  130 . In many embodiments, the safety system comprises at least one processor  77  and at least one memory  75  having program instructions  76  that when executed by the at least one processor are configured to cause the vehicle management system to unlock the door  130  of the self-driving vehicle  2  in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2 . 
     When smoke is present in the self-driving vehicle  2 , the rider&#39;s instinct may cause the rider to panic and open the door  130 . However, if the vehicle  2  is moving at relatively high rate of speed (e.g. greater than 15 mph) it may be very dangerous to open the door  130 . Accordingly, as shown in  FIG.  9   , the safety system may further comprise a speed detection system  134 . In some embodiments, the program instructions are configured to cause the vehicle management system to automatically unlock the door  130  in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2  and the speed detection system  134  determining that the self-driving vehicle  2  is moving at a first speed that is less than a first speed threshold. In some embodiments, the first speed threshold is less than 30 miles per hour. 
     Even still, in some embodiments, the program instructions are configured to cause the vehicle management system to unlock the door  130  in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2  and the speed detection system  134  determining that the self-driving vehicle  2  is moving at a first speed that is less than a first speed threshold. Furthermore, in some embodiments, the program instructions are configured to cause the motor to at least partially open the door  130  in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2  and the speed detection system  134  determining that the self-driving vehicle  2  is moving at a second speed that is less than a second speed threshold. In some embodiments, the second speed threshold is less than 15 miles per hour. 
     In some embodiments, the speed threshold for unlocking doors is less than 30 miles per hour, less than 20 miles per hour, less than 10 miles per hour, greater than 5 miles per hour, and/or greater than 1 mile per hour. In some embodiments, the speed threshold for opening doors is less than 21 miles per hour, less than 15 miles per hour, less than 5 miles per hour, and/or greater than 1 mile per hour. In some embodiments, the program instructions are not configured to unlock the doors and/or open the doors until at least a portion of the safety system verifies that the vehicle is no longer moving. 
     Many different types of speed detection systems can be used. In some embodiments, a self-driving vehicle  2  comprises a speed detection system  134  that enables the speedometer of the self-driving vehicle  2  to display a speed of the vehicle  2 . In some embodiments, the safety system uses GPS data (e.g., including locations of the vehicle every 0.1 second) to calculate the speed of the self-driving vehicle  2 . 
     Smoke inhalation may pose a serious health and safety risk to the rider(s). For example, a rider may inhale smoke from inside the cabin of the self-driving vehicle  2  and thereby become incapacitated leaving the rider trapped in the vehicle  2 . As such, it may be desirable to configure the self-driving vehicle  2  such that the door  130  automatically opens in response to the presence of smoke. Accordingly, the self-driving vehicle  2  may comprise a motor (e.g., of the door actuator  135 ) configured to at least partially open the door  130 . Furthermore, the program instructions may thereby be configured to cause the motor  135  to at least partially open the door in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2 . 
     With reference to  FIG.  17   , the self-driving vehicle may include a window  137  and a motor  136  configured to at least partially open the window  137 . In such embodiments, the program instructions may be configured to cause the motor  136  to at least partially open the window  137  in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2 . 
     In some embodiments, the smoke detection system  74  is configured to determine particle size of the smoke and concentration of the smoke. In such embodiments, the program instructions may be configured to cause the vehicle management system to automatically unlock the door  130  and/or open the door  130  of the self-driving vehicle  2  in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2  and the safety system determining the concentration of the smoke is greater than a predetermined threshold. It should be appreciated that the concentration of smoke may indicate the amount of combustion products found in a specified volume of air, commonly expressed as micrograms of emission per cubic meter of air. 
     Additionally, in some embodiments, the smoke detection system  74  is configured to detect a particle size of the smoke, and the vehicle management system is configured to unlock the door  130  in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2  and the safety system determining the particle size is smaller than a predetermined threshold. 
     Now, with reference to  FIG.  17   , many embodiments of the self-driving vehicle  2  comprise a window  137  and a motor  136  configured to at least partially open the window. In some embodiments, the smoke detection system  74  is configured to detect a particle size of the smoke and the program instructions are configured to cause the vehicle management system to unlock the door  130  in response to the safety system determining the particle size is smaller than a first predetermined threshold. Furthermore, the program instructions may also be configured to cause the motor  136  to at least partially open the window  137  in response to the safety system determining the particle size is larger than a second predetermined threshold. In some embodiments, the first predetermined threshold is smaller than or equal to the second predetermined threshold. However, in some embodiments, the first predetermined threshold is larger than the second predetermined threshold. 
     Many different ways of detecting particle sizes are described herein and/or incorporated by reference. In some embodiments, the smoke detection system  74  comprises an optical smoke detection system that uses several different infrared light wavelengths. The infrared light wavelengths selected for use in the optical smoke detection system can be chosen because they approximately correspond (in length) to particles sizes emitted in vehicle fires. 
     Furthermore, an optical smoke detector can use a first infrared light wavelength, a second infrared light wavelength (that is longer than the first wavelength), a third infrared light wavelength (that is longer than the second wavelength), and a fourth infrared light wavelength (that is longer than the third wavelength). Optical smoke detectors can sense smoke particles when smoke particles scatter a beam of the infrared light onto a light detector. An optical smoke detection system can detect an indication of smoke particle size by determining which of the first, second, third, and fourth wavelengths were scattered by the smoke particle. 
     As described heretofore, the self-driving vehicle  2  may comprise an actuator  139  configured to move the door lock  132  to an unlocked state. In some embodiments, the program instructions are configured to verify the door  130  is in the unlocked state in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2 . If the door  130  is in the locked state, the program instructions can be configured to cause the vehicle management system to put the door  130  in the unlocked state in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2 . In some embodiments, the program instructions can cause the vehicle management system to put the door  130  in the unlocked state in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2 , without first verifying the whether the door  130  is in the unlocked state. 
     In some embodiments, the smoke detection system  74  comprises a camera  10  and at least one of an ionization smoke detector and an optical smoke detector. In some embodiments, the camera  10  is configured to take a picture showing at least a portion of the cabin. Furthermore, the program instructions may thereby be configured to cause the motor  136  to at least partially open the window  137  in response to the safety system determining that the picture shows the smoke, and the program instructions are configured to cause the door lock actuator  139  to move the door lock  132  to the unlocked state in response to at least one of the ionization smoke detector and the optical smoke detector detecting the smoke inside the self-driving vehicle  2 . In some embodiments, program instructions are configured to at least partially open the window  137  in response to at least one of the ionization smoke detector and the optical smoke detector detecting the smoke inside the self-driving vehicle  2 . 
     Because of the risk of false positives, in some embodiments, the self-driving vehicle  2  is configured to verify the presence of smoke by receiving a verification from a rider present inside the vehicle  2 . Accordingly, as shown in  FIG.  23   , the program instructions are configured to automatically unlock the door lock  132  in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2  and the safety system receiving a verification input  171  from a rider. The verification input  171  may be configured to confirm a presence of the smoke  88 ,  89  in the self-driving vehicle  2 . 
     As shown in  FIGS.  2  and  3   , the self-driving vehicle  2  may comprise a display screen  93 . Now, with reference to  FIG.  23   , the program instructions may be configured to receive the verification input  171  from the rider via at least one of the display screen  93  and a button pressed by the rider in response to a visual request shown on the display screen  93 , such input(s) are referred to as display screen input  172 . Accordingly, in response to the smoke detection system  74  detecting the smoke, the program instructions may thereby be configured to cause the display screen  93  to emit, display, and/or present the visual request for the rider to confirm the presence of the smoke. The display screen  93  can be a touch screen. In some embodiments, the verification input  171  comprises a touch input  173  received by a touch sensor coupled to the self-driving vehicle  2  and communicatively coupled to the vehicle management system  181 . 
     The verification input  171  may define a variety of formats, such as a verbal response  174  from the rider. Accordingly, the self-driving vehicle  2  may comprise a microphone  186  and a speaker  86 . In such embodiments, the verification input  171  comprises a verbal response  174  received from the rider via the microphone  186  in response to the program instructions causing the speaker  86  to emit an audio request for the rider to confirm the presence of the smoke. In response to the smoke detection system  74  detecting the smoke, the program instructions may thereby be configured to cause the speaker  86  to emit the audio request. 
     The verification input  171  may take on additional forms, such as a physical gesture  175  made by the rider. In such embodiments, the self-driving vehicle  2  may comprise a camera  24   c , and the verification input  171  may comprise a gesture  175  made by the rider and recorded by the camera  24   c . In some embodiments, in response to the smoke detection system  74  detecting the smoke, the program instructions are configured to ask the rider to make a particular gesture if she believes there is smoke in the vehicle  2 . The gesture  175  can be nodding her head, using sign language, or any other gesture that the system can interpret. 
     In some embodiments, the program instructions do not ask the rider to make a particular gesture if she believes there is smoke in the vehicle. Instead, a vision recognition system can use artificial intelligence (such as AWS machine learning made by Amazon Web Services, Inc.) to identify gestures associated with how riders respond to smoke in the vehicle. For example, the rider may express panic via facial expressions, may make wild movements that are uncharacteristic of normal riding behavior, may make rapid movements to open the window or bang on the window, may yell for “help,” etc. 
     As shown in  FIG.  23   , in some embodiments, the safety system  170  and the smoke detection system  74  include a communication system  71 , a transmitter  72 , a receiver  73 , and an antenna  19 . The antenna  19  can communicatively couple at least one of the vehicle management system  181 , the safety system  170 , and the smoke detection system  74  to a remote computing device(s)  12 . Accordingly, the verification input  171  may comprise a wireless communication  176  transmitted from a remote computing device  12  of the rider to the safety system  170 . In this regard, the wireless communication  176  may comprise or be caused by a touch input received on a display screen of the remote computing device  12 , such as via an app running on the remote computing device  12 . In some embodiments, the wireless communication  176  comprises a text message or any transmission via radio communications, such as Bluetooth, cellular, WiFi, and the like. It should be appreciated that the wireless communication  176  may be transmitted directly or indirectly via intermediary communication systems  5 . 
     In some embodiments, the self-driving vehicle  2  is configured to provide additional ways of alerting the rider. For example, in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2 , the program instructions may be configured to cause the speaker  86  to emit audio instructions. The audio instructions may be configured to alert a rider regarding at least one of the smoke and the door being unlocked. In this regard, if the rider is not paying attention or is incapacitated (sleeping, drunk, disabled, and the like), then the audio instructions may provide for another way of alerting the rider and hopefully getting the rider&#39;s attention and thereby getting them to safety. 
     As shown in  FIG.  23   , in some embodiments, the self-driving vehicle  2  includes a fire extinguisher  180  arranged and configured to extinguish or at least control a fire inside a cabin of the vehicle  2 . Accordingly, the safety system  170  may comprise at least one processor and at least one memory having program instructions that when executed by the at least one processor are configured to cause the vehicle management system  181  to cause the fire extinguisher  180  to extinguish or at least control (i.e. contain) the fire in response to the smoke detection system  74  detecting smoke inside the cabin of the vehicle  2 . The fire extinguisher  180  may comprise a water fire extinguisher, AFFF foam fire extinguisher, carbon dioxide fire extinguisher, ABC powder fire extinguisher, water mist fire extinguisher, wet chemical fire extinguisher, and the like. In some embodiments, the fire extinguisher  180  is implemented as a fire suppression system using a combination of dry chemicals and/or wet agents to suppress fires. In some embodiments, the fire extinguisher  180  is an X-Tinguish® Fire Suppression System for Transportation made by Flame Guard USA having a manufacturing facility in Lake Barrington, Illinois. 
     As illustrated in  FIGS.  9 ,  14 , and  23   , the safety system  170  may also comprise a temperature detection system  110  coupled to the self-driving vehicle  2  and configured to detect a temperature inside at least a portion of self-driving vehicle  2 . Accordingly, the program instructions may be configured to cause the vehicle management system  181  to unlock the door  130  in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2  and the temperature detection system  74  detecting the temperature greater than a predetermined temperature threshold. 
     In some embodiments, the temperature detection system  110  comprises a camera system configured to identify the smoke. In some embodiments, cameras  24   a ,  24   b ,  24   c  are configured to take pictures based on detecting light that is visible to the human eye. In some embodiments, at least some of the cameras  24   a ,  24   b ,  24   c  are thermal imaging cameras configured to detect the heat from a fire. The thermal imaging cameras can be part of the temperature detection system  110 . A thermal imaging camera can be an infrared camera made by FLIR Systems, Inc. Embodiments can analyze infrared radiation to detect fires in a vehicle  2 . In some embodiments, the infrared radiation is rendered as visible light to aid in heat analysis. Program instructions  76  can analyze the infrared light detected by infrared cameras to detect fires inside the vehicle  2 . 
     The fire may be from a small object such as a laptop computer located inside the cabin of the vehicle  2 . Program instructions  76  can cause an image analysis system  70  to analyze a thermal image taken by one of the cameras  24   a ,  24   b ,  24   c  to determine if the thermal image comprises a portion that has a temperature over a predetermined threshold (e.g., at least 150 degrees Fahrenheit, at least 180 degrees Fahrenheit, at least 200 degrees Fahrenheit). The program instructions  76  can be configured to respond to detecting the temperature over the predetermined threshold in any of the ways in which other embodiments respond to detecting smoke. 
     In some embodiments, the temperature detection system  110  is configured to precisely identify the location of the fire and/or smoke. In some embodiments, the temperature detection system  110  is configured to determine the temperature located within 36 inches of the smoke, 24 inches of the smoke, 12 inches of the smoke, 1 inch of the smoke, and distances greater than 1 inch from the smoke. 
       FIGS.  18 - 22    illustrate additional seat  51  and seat belt  153  embodiments that can be used with any of the other embodiments described herein and/or incorporated by reference. The seat  51  can be located in the vehicle  2 . The camera device  10  can be located inside a cabin of the vehicle  2 . The smoke detection system  74  can be located inside the cabin of the vehicle  2 . Additional details related to FIGS. 18-22 are described in U.S. patent application Ser. No. 16/266,698. The entire contents of U.S. patent application Ser. No. 16/266,698 are incorporated herein by reference. 
     A seat belt is a restraining device configured to hold a rider in a seat of a vehicle during a collision. Many different types of seat belts can be used with the embodiments described herein and/or incorporated by reference. 
     Seat belt embodiments can use two-point seat belts, lap seat belts, shoulder seat belts, sash seat belts, three-point seat belts, four-point seat belts, five-point seat belts, six-point seat belts, eight-point seat belts, and any other type of restraining device configured to hold a rider in a seat of a vehicle during a collision. 
       FIG.  18    illustrates a side view of a first seat  51 . A camera device  10  is also shown in  FIG.  18   . The camera device  10  can be configured to detect if a rider is sitting in the first seat  51 . An optional shoulder strap is hidden in  FIG.  18   . 
       FIG.  19    illustrates a seat belt  153  having anchor points  159   a ,  159   b ,  159   c ,  159   d  that can be bolted to a frame of a self-driving vehicle  2 . The seat belt  153  can comprise a strap  105 . The strap  105  can include webbing. The strap  105  can be flexible. The strap  105  can be rigid. Many other types of seat belts can be used. 
     The seat belt  153  can include a retractor  107  that is spring loaded to apply a force to the strap  105  that wraps at least a portion of the seat belt  153  around a rotating portion of the retractor  107 . Pulling the seat belt tongue  106  toward the buckle  108  can create a triangular shape that forms a shoulder belt and a lap belt as the strap  105  slides through the pillar loop  104 . 
       FIG.  20    illustrates a perspective view of portions of the seat belt  153 . Inserting the tongue  106  (which can be metal) into an opening  109  of the buckle  108  can “buckle” the seat belt  153 . 
     Inserting the tongue  106  into the opening  109  can compress a spring  160 . The compression of the spring  160  can cause the buckle  108  to eject the tongue  106  when a rider presses a button  161  configured to unbuckle the seat belt  153 . 
     As shown in  FIG.  21   , an actuator  141  can also be configured to depress the button  161  (e.g., by pulling the button assembly downward into the outer housing  163  of the buckle  108 ). The retractor  107  (shown in  FIG.  19   ) can be spring loaded such that once the buckle  108  ejects the tongue  106  (e.g., in response to the button  161  moving), the retractor  107  reels in at least a portion of the strap  105  to pull the seat belt  153  off of the rider to enable the rider to exit the vehicle  2 . 
     In some embodiments, the actuator  141  is an electric linear actuator controlled by the computer system  7  shown in  FIG.  9   . (Actuators can be purchased from many companies including Actuonix Motion Devices Inc.) Program instructions  76  can be configured to cause the actuator  141  to move the button  161  in response to various items. 
     The actuator  141  can comprise a rod  162  configured to extend (e.g., to push the button  161  upward) and retract (e.g., to depress the button  161 ). A distal end of the rod  162  can comprise an anchor  164  that couples the distal end of the rod  162  to the button  161 . A lower end of the actuator  141  can comprise an anchor  165  that is coupled to the outer housing  163 . 
     Referring now primarily to  FIGS.  9  and  18 - 22   , a seat belt sensor  155  is configured to detect at least one of a buckled state of the first seat belt  153  and an unbuckled state of the first seat belt  153 . In some embodiments, a seat belt sensor detects if a strap  105  is coupled to an anchor such that the seat belt  153  is arranged to restrain a rider in the event of a collision. In some embodiments, a seat belt sensor  155  detects if there is strain on the strap  105  (e.g., due to one end of the strap  105  being coupled to an anchor and another end of the strap  105  being pulled by a retractor  107 ) such that the seat belt  153  is arranged to restrain a rider in the event of a collision. Many types of seat belt sensors can be used with the embodiments described herein and/or incorporated by reference. 
     U.S. Pat. No. 7,093,515 teaches a seat belt sensor to detect whether a seat belt is in a buckled state: “The buckle switch  17  is turned off when the seat belt  14  is fastened by inserting and thereby hooking a tongue  15  to a buckle  16 . The buckle switch  17  is turned on when the tongue  15  is not inserted into and hooked on the buckle  16  and thus the seat belt  14  is unfastened.” See FIG. 4 of U.S. Pat. No. 7,093,515. The entire contents of U.S. Pat. No. 7,093,515 are incorporated by reference herein. 
     U.S. Pat. Nos. 5,960,523; 6,554,318; and 5,871,063 teach about seat belt sensors. The entire contents of U.S. Pat. Nos. 5,960,523; 6,554,318; and 5,871,063 are incorporated by reference herein. 
     U.S. Pat. Nos. 5,965,827; 5,996,421; 5,765,774; 6,205,868; and 6,357,091 teach about seat belt sensors. The entire contents of U.S. Pat. Nos. 5,965,827; 5,996,421; 5,765,774; 6,205,868; and 6,357,091 are incorporated by reference herein. 
     In some embodiments, a seat belt sensor  155  comprises a switch that is triggered by inserting the tongue  106  into the opening  109  of the buckle  108 . The switch can be a mechanical switch. The switch can be an electrical component configured to, for example, complete an electrical current in response to inserting the tongue  106  into the opening  109  of the buckle  108 . Many different types of electrical switches can be used. Some embodiments use a reed switch. 
     Some embodiments use a light switch configured such that inserting the tongue  106  into the opening  109  of the buckle  108  blocks light emitted from a light source (located inside the buckle  108 ) from reaching a light sensor (located inside the buckle  108 ). If the buckle sensor does not detect the light from the light source, then the system determines that the seat belt  153  is “buckled.” 
     In some embodiments, the tongue  106  comprises a signal emitting portion and the buckle  108  comprises a signal receiving portion. If the buckle sensor does not detect the signal, then the system determines that the seat belt  153  is “unbuckled.” 
     In some embodiments, the tongue  106  comprises a signal receiving portion and the buckle  108  comprises a signal emitting portion. If the buckle sensor does not detect the signal, then the system determines that the seat belt  153  is “unbuckled.” 
     In some embodiments, the buckle sensor  155  is a strain gauge coupled to the strap  105  such that when the seat belt  153  is “buckled,” the resulting strain is sensed by the buckle sensor  155  (such that the system can determine that the seat belt  153  is “buckled”). 
     A seat belt may be extendable (e.g., the retractor  107  may allow additional strap length to unroll) but still may be arranged to help secure the rider if a collision occurs. In some embodiments, a seat belt arranged across a lap of a rider, across a chest and shoulder area of a rider, and/or across a frontside (e.g., of an upper body) of the rider is arranged to help secure a rider if a collision occurs. 
     As used herein, “buckled state” is used broadly to mean that the seat belt is arranged to help secure a rider if a collision occurs. As used herein, “unbuckled state” is used broadly to mean that the seat belt is not arranged to help secure a rider if a collision occurs. In some embodiments, if the seat belt is simply located at the side of the rider and the tongue  106  is not coupled to the buckle  108 , then the seat belt is not arranged to help secure the rider if a collision occurs. 
     Some seat belts do not have a buckle but can still be placed in a “buckled state” if the seat belt is arranged to help secure a rider if a collision occurs. A seat belt (even without a buckle) can be positioned across a lap of a rider such that the seat belt is arranged to help secure a rider if a collision occurs. 
     Embodiments can use the terminology “uncoupled state” for a seat belt that is not arranged to help secure a rider if a collision occurs and “coupled state” for a seat belt that is arranged to help secure a rider if a collision occurs. 
     Embodiments can use the terminology “unfastened state” for a seat belt that is not arranged to help secure a rider if a collision occurs. Embodiments can use the terminology “fastened state” for a seat belt that is arranged to help secure a rider if a collision occurs. 
     Motorized seat belts can be placed in a buckled state via a motor that moves the seat belt into a position to help secure a rider if a collision occurs. The seat belt can begin in an unbuckled state that enables the rider to enter the vehicle and sit in the seat. Then, the motor can move the seat belt (e.g., along a track coupled to a frame of the vehicle) into a buckled state such that the seat belt is in a position to help secure the rider if a collision occurs. In some motorized seat belts, actuating a buckle is not necessary to transition from an unbuckled state to a buckled state because movement of an end of the seat belt along the track (rather than actuating the buckle) places the seat belt in a position to help secure a rider if a collision occurs. The entire contents of U.S. Pat. No. 4,995,640 are incorporated by reference herein. 
     In some embodiments, a seat-belt monitoring system comprises a first occupancy sensor  57  configured to detect the rider sitting in the first seat  51 . Occupancy sensor embodiments can use any type of sensor that enables the seat-belt monitoring system to detect whether a rider is located in a seat. Many types of sensors can be used. 
     In some embodiments, an occupancy sensor comprises a camera (e.g.,  10 ) configured to take a picture of the rider. A computer system  7  can comprise program instructions  76  configured to visually analyze the picture to determine if the picture shows a rider (a person) sitting in a seat  51 . For example, Amazon Web Services, Inc. provides an application programming interface (“API”) called “Amazon Rekognition” to automatically recognize people and objects in pictures. A communication system  71  of a self-driving vehicle  2  can send the picture to the API for analysis. The API can then tell a computer system  7  if the picture shows a rider located in the seat of the vehicle. The API can also tell a computer system  7  if the picture shows the seat belt in a buckled state or in an unbuckled state. Thus, the API can enable a camera-based system to serve as both an occupancy sensor (to determine if a person is sitting in the seat) and as a seat belt sensor configured to detect a buckled state of the seat belt and an unbuckled state of the seat belt. 
     In some embodiments, an occupancy sensor comprises a camera. U.S. Pat. No. 7,505,841 includes an occupancy sensor that comprises a camera. The entire contents of U.S. Pat. No. 7,505,841 are incorporated by reference herein. U.S. Pat. No. 7,415,126 includes an occupancy sensor that comprises a camera. The entire contents of U.S. Pat. No. 7,415,126 are incorporated by reference herein. 
     In some embodiments, an occupancy sensor comprises a pressure sensor configured to detect whether a rider is sitting in a seat of a vehicle. The pressure sensor can collect data indicative of a rider&#39;s weight. The rider likely has her feet on the floor, so the weight data may not reflect the rider&#39;s entire weight. Even so, the weight data can help identify the rider. For example, a first rider may have a weight of 120 pounds with 30 pounds resting on the floor (due to the first rider&#39;s feet being on the floor) and 90 pounds resting on a first seat. The distribution between the first rider&#39;s weight on the floor and weight on the first seat may vary (e.g., by plus or minus fifteen percent) depending on how the first rider is sitting on the first seat, but generally is fairly consistent. 
     A second rider may have a weight of 200 pounds with 50 pounds resting on the floor (due to the second rider&#39;s feet being on the floor) and 150 pounds resting on a second seat. The distribution between the second rider&#39;s weight on the floor and weight on the second seat may vary (e.g., by plus or minus fifteen percent) depending on how the second rider is sitting on the second seat, but generally is fairly consistent. 
     Program instructions  76  can be configured to use the weight on the seat (and/or on the floor) to help identify which rider is sitting in a particular seat. For example, the first rider may travel in four vehicles on four different days with recorded weights (e.g., in seats of each vehicle) of 90+/− 8 pounds, 92+/− 7 pounds, 91+/− 8 pounds, and 89+/− 7 pounds. The second rider may travel in four vehicles on four different days with recorded weights (e.g., in seats of each vehicle) of 150+/− 9 pounds, 148+/− 7 pounds, 148+/− 5 pounds, and 151+/− 8 pounds. 
     If the first and second riders are located in a vehicle, the program instructions can be configured to use the weight history data of the first and second riders to determine which rider is located in a particular seat. For example, “seat A” may detect a weight of 92 pounds and “seat B” may detect a weight of 148 pounds. The computer system can then compare the detected weights to a weight history in a profile of each rider to determine that the first rider is located in “seat A” and the second rider is located in “seat B.” If a seat belt sensor of “seat B” detects an unbuckled state, the program instructions can be configured to fine an account of the second rider (rather than mistakenly fining an account of the first rider). 
     A weight (e.g., detected by an occupancy sensor) over a predetermined threshold can be used to enable the system to determine that the weight is due to a person rather than another object such as a laptop, a backpack, or a grocery bag. In some embodiments, the predetermined threshold is greater than 20 pounds, greater than 30 pounds, less than 50 pounds, and/or less than 70 pounds. 
     U.S. Pat. No. 6,609,054 includes occupancy sensor information. The entire contents of U.S. Pat. No. 6,609,054 are incorporated by reference herein. 
     U.S. Pat. No. 6,918,612 includes occupancy sensor information. The entire contents of U.S. Pat. No. 6,918,612 are incorporated by reference herein. 
     U.S. Pat. No. 6,927,678 includes occupancy sensor information. The entire contents of U.S. Pat. No. 6,927,678 are incorporated by reference herein. 
     U.S. Pat. No. 6,920,256 includes occupancy sensor information. The entire contents of U.S. Pat. No. 6,920,256 are incorporated by reference herein. Occupancy sensor systems can use effects of a presence of a rider sitting in a seat to detect whether a rider is sitting in a seat. In some embodiments, light from a light source is blocked by the rider sitting on a seat. The blocked light is not detected by a light sensor. Failing to detect the light is a signal that a rider is sitting in the seat. 
     In some embodiments, an occupancy sensor comprises a weight sensor  215 . U.S. Pat. No. 6,636,792 includes weight sensor information. The entire contents of U.S. Pat. No. 6,636,792 are incorporated by reference herein. 
     The disclosure also includes a safety system  170  comprising a self-driving vehicle  2  configured to transport a rider, a vehicle management system configured to autonomously drive the self-driving vehicle  2 , a seat  51  coupled to the self-driving vehicle  2 , and a seat belt  153  configured to alternatively have a buckled state and an unbuckled state. In many embodiments, the safety system  170  includes a smoke detection system  74  coupled to the self-driving vehicle  2  and configured to detect smoke inside a cabin of the self-driving vehicle  2 . 
     In the buckled state the seat belt  153  is configured to secure the rider in the seat  51  and in the unbuckled state the seat belt  153  is configured to enable the rider to exit the seat  51 . The seat belt  153  is configured to alternatively have a buckled state and an unbuckled state. In other words, if the seat belt  153  is in the buckled state, the seat belt  153  is not in the unbuckled state. If the seat belt  153  is in the unbuckled state, the seat belt  153  is not in the buckled state. 
     In many embodiments, the safety system  170  further includes at least one processor  77  and at least one memory  75  having program instructions  76  that when executed by the at least one processor  77  are configured to cause the vehicle management system to switch the seat belt  153  from the buckled state to the unbuckled state in response to the smoke detection system detecting the smoke inside the self-driving vehicle  2 . Some embodiments comprise at least one processor  77  and at least one memory  75  having program instructions  76  that when executed by the at least one processor  77  are configured to cause the vehicle management system to unbuckle the seat belt  153  in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2 . The program instructions  76  can cause the vehicle management system to change the seat belt  153  from the buckled state to the unbuckled state in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2 . The program instructions  76  can also cause the vehicle management system to change the seat belt  153  from the unbuckled state to the buckled state. In some embodiments, the rider manually buckles the seat belt and can manually unbuckle the seat belt  153 , but in some cases, the vehicle management system unbuckles the seat belt  153  before the rider even tries to unbuckle the seat belt. 
     As illustrated in  FIGS.  21  and  22   , the safety system  170  may further include a first actuator  141  configured to switch the seat belt  153  from the buckled state to the unbuckled state. In some embodiments, the program instructions  76  are configured to send a control signal to the first actuator  141  in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2 . In some embodiments, the control signal is configured to cause the first actuator  141  to switch the seat belt  153  from the buckled state to the unbuckled state. 
     Now, with reference to  FIGS.  18  and  20   , some embodiments of the safety system  170  include a seat belt sensor  155  configured to detect the buckled state of the seat belt  153 . In this regard, the program instructions  76  are configured to cause the vehicle management system to switch the seat belt  153  from the buckled state to the unbuckled state in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2  and the seat belt sensor  155  detecting the buckled state. 
     Additionally, in some embodiments, the safety system  170  further includes an occupancy sensor  57  configured to detect the rider sitting in the seat  51 . In such embodiments, the program instructions  76  are configured to cause the vehicle management system to switch the seat belt  153  from the buckled state to the unbuckled state in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2  and the occupancy sensor  57  detecting the rider sitting in the seat  51 . 
     In some embodiments, the safety system  170  includes both a seat belt sensor  155  and an occupancy sensor  57 . In this regard, the program instructions  76  may be configured to cause the vehicle management system to switch the seat belt  153  from the buckled state to the unbuckled state in response to: the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2 , the occupancy sensor  57  detecting the rider sitting in the seat  51 , and the seat belt sensor  155  detecting the buckled state. 
     In some embodiments, the seat belt sensor  155  directly detects the buckled state of the seat belt  153 . In some embodiments, the seat belt sensor  155  indirectly detects the buckled state of the seat belt  153  by not detecting the unbuckled state (such that the system knows the buckled state is present because the unbuckled state is not detected). If the system detects that the seat belt  153  is not unbuckled, then the system can use that information to determine that the seat belt  153  is buckled. 
     Danger is inherent when traveling by vehicle. This danger can be worsened based upon the speed that a vehicle is traveling. Accordingly, various safety systems are arranged and configured to keep riders safely buckled in their seat  51  if the self-driving vehicle  2  is traveling above various speed thresholds, such as 30 miles per hour. With reference to  FIG.  9   , in some embodiments, the safety system  170  includes a speed detection system  134 . Accordingly, the program instructions  76  may be configured to cause the vehicle management system to automatically switch the seat belt  153  from the buckled state to the unbuckled state in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2  and the speed detection system  134  determining that the self-driving vehicle  2  is moving at a first speed that is less than a first speed threshold. In some embodiments, the first speed threshold is less than 30 miles per hour. In some embodiments, the first speed threshold is greater than one mile per hour. In some embodiments, the first speed threshold is less than 30 miles per hour, less than 20 miles per hour, less than 10 miles per hour, greater than 5 miles per hour, and/or greater than one mile per hour. Many different types of speed detection systems can be used. In some embodiments, a self-driving vehicle  2  comprises a speed detection system  134  that enables the speedometer of the self-driving vehicle  2  to display a speed of the vehicle  2 . In some embodiments, the safety system  170  uses GPS data (e.g., including locations of the vehicle every second) to calculate the speed of the self-driving vehicle  2 . 
     As shown in  FIGS.  15  and  16   , in some embodiments, the self-driving vehicle comprises a door  130 , a door lock  132  configured to impede opening the door  130 , and a door lock actuator  139  configured to arrange the door lock  132  to an unlocked state. The program instructions  76  may thereby be configured to cause the door lock actuator  139  to unlock the door  130  in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2 . 
     Additionally, in some embodiments, the self-driving vehicle  2  further includes a door actuator  135  configured to at least partially open the door  130 . In some embodiments, the program instructions are configured to cause the door actuator  135  to at least partially open the door  130  in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2 , and the safety system  170  further comprises a speed detection system  134 , and the program instructions are configured to cause the vehicle management system to switch the seat belt  153  from the buckled state to the unbuckled state in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2  and the speed detection system  134  determining that the self-driving vehicle  2  is moving at a first speed that is less than a first speed threshold. The program instructions  76  may thereby be configured to cause the door actuator  135  to at least partially open the door  130  in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2  and the speed detection system  134  determining that the self-driving vehicle  2  is moving at a second speed that is less than a second speed threshold. In some embodiments, the second speed threshold is less than 15 miles per hour, less than 10 miles per hour, less than 5 miles per hour, greater than 5 miles per hour, and/or greater than one mile per hour. In some embodiments, the first speed threshold is greater than 1 mile per hour and is greater than the second speed threshold. 
     In some embodiments, the speed threshold for unbuckling a seat belt  153  is less than 30 miles per hour, less than 20 miles per hour, less than 10 miles per hour, greater than 5 miles per hour, and/or greater than 1 mile per hour. 
     In some embodiments, the speed threshold for opening doors  130  is less than 21 miles per hour, less than 15 miles per hour, less than 5 miles per hour, and/or greater than 1 mile per hour. In some embodiments, the program instructions are not configured to unbuckle the seat belt  153  and/or open the doors  130  until at least a portion (e.g., the speed detection system  134 ) of the safety system  170  verifies that the vehicle  2  is no longer moving. 
     In many embodiments, the self-driving vehicle  2  comprises a window  137  and a motor  136  configured to at least partially open the window  137 . In some embodiments, in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2  the program instructions  76  are configured to cause the motor  136  to at least partially open the window  137  prior to the seat belt  153  switching from the buckled state to the unbuckled state. For example, if the vehicle  2  is traveling 70 miles per hour, the window  137  might open as soon as the smoke detection system  74  detects smoke, but the seat belt  153  would not unbuckle until the vehicle  2  is going much slower. 
     In some embodiments, the smoke detection system  74  is configured to detect a concentration of the smoke, which may be indicative of the type of fire. Accordingly, the program instructions  76  are configured to cause the vehicle management system to automatically switch the seat belt  153  from the buckled state to the unbuckled state in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2  and the safety system  170  determining the concentration of the smoke is greater than a predetermined threshold. As used herein, to “switch” the seat belt from the buckled state to the unbuckled state does not necessarily require a physical switch or a mechanical switch. 
     Furthermore, in some embodiments, the smoke detection system  74  is configured to detect a particle size of the smoke. In this regard, the vehicle management system can be configured to switch the seat belt  153  from the buckled state to the unbuckled state in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2  and the safety system  170  determining the particle size is smaller than a predetermined threshold. Contra, in some embodiments, the vehicle management system can even be configured to switch the seat belt  153  from the buckled state to the unbuckled state in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2  and the safety system  170  determining the particle size is greater than a predetermined threshold. 
     The system may also be configured to perform dual responses with respect to the smoke particle size detected. In some embodiments, wherein the self-driving vehicle  2  comprises a window  137  and a motor  136  configured to at least partially open the window  137 , the smoke detection system  74  is configured to detect a particle size of the smoke, the program instructions  76  are configured to cause the vehicle management system to switch the seat belt  153  from the buckled state to the unbuckled state in response to the safety system  170  determining the particle size is smaller than a first predetermined threshold, and the program instructions  76  are configured to cause the motor  136  to at least partially open the window  137  in response to the safety system  170  determining the particle size is larger than a second predetermined threshold. Even still, in some embodiments, the program instructions  76  are configured to cause the vehicle management system to switch the seat belt  153  from the buckled state to the unbuckled state in response to the safety system  170  determining the particle size is greater than a first predetermined threshold, and the program instructions  76  are configured to cause the motor  136  to at least partially open the window  137  in response to the safety system  170  determining the particle size is smaller than a second predetermined threshold. Generally, it should be appreciated that any combination of events disclosed herein may be caused by the vehicle management system in response to the smoke detection system  74  determining that the particle sizes are greater than or less than the first predetermined threshold or the second predetermined threshold. The second predetermined threshold can be larger than the first predetermined threshold. 
     Many different ways of detecting particle sizes are described herein and/or incorporated by reference. As illustrated in  FIGS.  10 ,  11 , and  23   , the smoke detection system  74  can include an optical smoke detection system  91  that uses several different infrared light wavelengths. The infrared light wavelengths selected for use in the optical smoke detection system  91  can be chosen because they approximately correspond (in length) to particles sizes emitted in vehicle fires. 
     An optical smoke detector can use a first infrared light wavelength, a second infrared light wavelength (that is longer than the first wavelength), a third infrared light wavelength (that is longer than the second wavelength), and a fourth infrared light wavelength (that is longer than the third wavelength). Optical smoke detectors can sense smoke particles when smoke particles scatter a beam of the infrared light onto a light detector. An optical smoke detection system can detect an indication of smoke particle size by determining which of the first, second, third, and fourth wavelengths were scattered by the smoke particle. 
     Some fire and/or smoke events may constitute acute dangerous situations while other smoke events pose no immediate danger, but are rather just a nuisance. In some embodiments, wherein the self-driving vehicle  2  comprises a window  137  and a motor  136  configured to at least partially open the window  137 , the smoke detection system  74  comprises a camera  24   a  and at least one of an ionization smoke detector  90  and an optical smoke detector  91 , wherein the camera  24   a  is configured to take a picture showing at least a portion of the cabin. In such embodiments, the program instructions  76  may be configured to cause the motor  136  to at least partially open the window  137  in response to the safety system  170  determining that the picture shows the smoke, and the program instructions  76  are configured to cause the vehicle management system to switch the seat belt  153  from the buckled state to the unbuckled state in response to at least one of the ionization smoke detector and the optical smoke detector detecting the smoke inside the self-driving vehicle. In some embodiments, program instructions  76  are configured to at least partially open the window  137  in response to at least one of the ionization smoke detector  90  and the optical smoke detector  91  detecting the smoke inside the self-driving vehicle  2 . 
     Elevated temperature may also be an indication of a dangerous situation versus a nuisance. As shown in  FIGS.  9 ,  14 , and  23   , in some embodiments, the safety system  170  further includes a temperature detection system  110  coupled to the self-driving vehicle  2  and configured to detect a temperature inside at least a portion of the self-driving vehicle  2 . Accordingly, in some embodiments, the program instructions  76  are configured to cause the vehicle management system to switch the seat belt  153  from the buckled state to the unbuckled state in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle and the temperature detection system detecting that the temperature is greater than a predetermined temperature threshold. Conversely, in some embodiments, the program instructions  76  are configured to cause the vehicle management system to leave the seat belt  153  in its existing state (whether buckled or unbuckled) and at least partially open the window  137  in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle and the temperature detection system detecting that the temperature is lower than a predetermined temperature threshold. 
     In some embodiments, the temperature detection system  110  comprises a thermal imaging camera. The thermal imaging camera can be an infrared camera made by FLIR Systems, Inc. In some embodiments, the temperature detection system  110  comprises a thermometer. 
     The safety system  170  may also be configured to react according to various objects located around the self-driving vehicle  2   a . In some embodiments, the safety system  170  further includes an object detection system configured to detect a second vehicle  2   b  and having at least one of a camera, a radar, and a lidar. In some embodiments, at least one of the camera, the radar, and the lidar is coupled to the self-driving vehicle  2  to enable the objection detection system to detect the second vehicle  2   b , and the program instructions  76  are configured to cause the vehicle management system to switch the seat belt  153  from the buckled state to the unbuckled state in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2   a  and in response to at least one of: the object detection system detecting that the second vehicle  2   b  is at least a predetermined distance from the self-driving vehicle  2   a , the object detection system detecting that the second vehicle  2   b  is not on a collision course with the self-driving vehicle  2   a , and the vehicle management system determining, based on data from the object detection system, that the second vehicle  2   b  has less than a predetermined risk threshold of colliding with the self-driving vehicle  2   a.    
     In some embodiments, the program instructions  76  are configured to automatically switch the seat belt  153  from the buckled state to the unbuckled state in response to the smoke detection system  74  detecting the smoke inside the self-driving vehicle  2  and the safety system  170  receiving a verification input  171  from a rider. The verification input  171  is configured to confirm a presence of the smoke in the self-driving vehicle  2 . 
     The entire contents of the following patents are incorporated by reference herein: U.S. Pat. Nos. 10,223,844; 10,282,625; 10,289,922; 10,471,804; and 10,479,319. 
     A system can be configured to take actions to protect riders from fires. In some embodiments, a smoke detection system is coupled to the vehicle and is configured to detect smoke inside a cabin of the vehicle; and a vehicle management system that is configured to autonomously drive the vehicle is configured to automatically reduce a speed of the vehicle in response to the smoke detection system detecting the smoke inside the vehicle. 
     A system can be configured to take actions to protect riders from elevated temperatures detected inside the vehicle. An infrared camera can be coupled to a ceiling of the vehicle such that the infrared camera is configured to “see” hot spots, which can be signs of a burning cigarette, a vaping device, a laptop fire, and/or a vehicle fire. Some embodiments use infrared cameras made by FLIR Systems, Inc. 
     Some embodiments use image recognition and artificial intelligence to identify whether the elevated temperature is due to a burning cigarette, a vaping device, an electronic device (e.g., a laptop) fire, and/or a vehicle fire. Program instructions can respond to detecting a burning cigarette or an active vaping device by causing a speaker of the vehicle to emit a verbal warning to cease smoking or vaping. Program instructions can respond to a fire by causing the vehicle to enter a stopping mode that reduces the time during which the rider is exposed to the dangers of the fire. 
     Temperature detection systems  110  can also be positioned to detect elevated temperatures in any part of the vehicle. A motor compartment  122  can comprise at least one motor. Many different parts located inside the motor compartment  122  can overheat and present a fire hazard. Rather than wait for the overheating to cause a fire, some embodiments include program instructions that cause various actions in response to detecting high temperatures and/or a temperature trajectory that indicates that the temperature is increasing dangerously quickly. As a result, the program instructions can prevent riders from being exposed to fires (e.g., by taking action prior to a fire starting). 
     Temperature detection systems  110  can use many different devices to detect a temperature (e.g., every 0.1 seconds) of a portion of a vehicle. Program instructions can track the temperature readings to analyze trends that could indicate potential hazards. 
     Temperature detection systems  110  can comprise at least one thermocouple  116 . A thermocouple  116  can detect a voltage that varies based on temperature. The voltage can be calibrated such that the system can convert the voltage reading to a temperature reading. 
     Temperature detection systems  110  can comprise at least one resistance temperature detector  121  (which is sometimes referred to as a resistance thermometer). The resistance temperature detector  121  can comprise a wire with a resistance that varies predictably and repeatably with temperature. The resistance temperature detector  121  can be calibrated such that the system can convert the resistance reading to a temperature reading. 
     Temperature detection systems  110  can comprise at least one thermistor  123 . Thermistors  123  can be resistors with a resistance that varies according to temperature. Thermistors  123  can have a negative temperature coefficient or a positive temperature coefficient. A thermistor  123  can be calibrated such that the system can convert the resistance reading to a temperature reading. 
     Temperature detection systems  110  can comprise at least one pyrometer  126 . A pyrometer  126  does not need to touch a surface to detect a temperature of the surface. A pyrometer  126  can be configured to detect a temperature of a surface from a distance by measuring the thermal radiation emitted by the surface. The thermal radiation detected can be converted to a temperature. 
     Temperature detection systems  110  can comprise at least one thermometer  128 . Many different types of thermometers can be used with the embodiments described herein. 
     Embodiments can determine that a temperature exceeds a threshold. The threshold can be a specific temperature, but can also be an indication of temperature. The indication can be many things including a resistance value (e.g., detected by a resistance temperature detector  121  or a thermistor  123 ), a thermal radiation value (e.g., detected by a pyrometer  126 ), a voltage (e.g., detected by a thermocouple  116 ), infrared data (e.g., detected by an infrared camera), another temperature indication (e.g., detected by a thermometer  128 ), etc. In some embodiments, the threshold is a temperature indication threshold (e.g., a resistance value, a voltage value, a thermal radiation value, an infrared value, or another value indicative of temperature). 
     In some embodiments, a camera  10 , a thermocouple  116 , a resistance temperature detector  121 , a thermistor  123 , an integrated circuit  125 , a pyrometer  126 , and/or a thermometer  128  is placed in a passenger cabin  120  to detect elevated temperatures that could be indicative of hazards to riders. 
     In some embodiments, a camera  10 , a thermocouple  116 , a resistance temperature detector  121 , a thermistor  123 , an integrated circuit  125 , a pyrometer  126 , and/or a thermometer  128  is placed in a motor compartment  122  to detect elevated temperatures that could be indicative of conditions that could prevent the vehicle from functioning properly in the near future and/or could be indicative of a fire hazard. 
     In some embodiments, a camera  10 , a thermocouple  116 , a resistance temperature detector  121 , a thermistor  123 , an integrated circuit  125 , a pyrometer  126 , and/or a thermometer  128  is placed in a battery compartment  202  to detect elevated temperatures that could be indicative of conditions that could prevent the battery  204  from functioning properly in the near future and/or could be indicative of a fire hazard. In some cases, a high temperature and/or a rapidly increasing temperature trajectory could be indicative of a dangerous battery temperature and/or a runaway battery temperature, which can be hazardous to riders. 
     Lithium-ion batteries have impressive energy densities, but also are potentially dangerous to riders. Short circuits can cause dangerous battery temperatures. 
     Charging the battery can also pose hazards. Overcharging the battery can cause dangerous battery temperatures. Using too high of a charging current can cause dangerous battery temperatures. 
     In some embodiments, a thermocouple  116 , a resistance temperature detector  121 , a thermistor  123 , an integrated circuit  125 , a pyrometer  126 , and/or a thermometer  128  is coupled to an exterior and/or an interior of a battery  204 . 
     In some embodiments, a thermocouple  116 , a resistance temperature detector  121 , a thermistor  123 , an integrated circuit  125 , a pyrometer  126 , and/or a thermometer  128  is coupled to an exterior and/or an interior of a battery housing  203 . 
     In some embodiments, a camera  10 , a thermocouple  116 , a resistance temperature detector  121 , a thermistor  123 , an integrated circuit  125 , a pyrometer  126 , and/or a thermometer  128  is placed in a cargo compartment  124  to detect elevated temperatures that could be indicative of conditions that could be indicative of a fire hazard. 
     In some embodiments, a safety system comprises a self-driving vehicle  2 ; a temperature detection system  110  coupled to the self-driving vehicle  2  and configured to detect a first temperature  184  of a first portion  183  of the self-driving vehicle  2 ; and a vehicle management system  65  configured to autonomously drive the self-driving vehicle  2 . 
     A vehicle management system  65  can comprise a vehicle guidance system  117 . In some embodiments, at least a portion of the vehicle guidance system  117  is coupled to the vehicle  2 . A vehicle guidance system  117  can comprise radar  118 , lidar  119 , ultrasonic sensors, cameras  111 , and any other sensing devices configured to enable the vehicle  2  to detect objects by collecting and analyzing data. 
     The data can be from a radar  118 . Radar is an object-detection system that uses radio waves to determine the range, angle, and/or velocity of objects. A radar  118  can comprise a transmitter producing electromagnetic waves in the radio or microwave domain, a transmitting antenna, a receiving antenna (which can be the same antenna as the transmitting antenna), a receiver, and/or a processor to determine properties of the objects detected by the radar. As a result, the radar  118  can generate three-dimensional data representing an area outside the vehicle guidance system  117 . 
     The data can be from a lidar  119 . Lidar uses light to detect objects. In some embodiments, the lidar  119  is a Velodyne VLS-128 made by Velodyne LiDAR, Inc. 
     A lidar  119  can be located on a top portion of the vehicle guidance system  117  to provide a 360-degree view of the area around the self-driving vehicle  2 . As a result, the first lidar  119  can generate three-dimensional data representing an area outside the vehicle guidance system  117 . 
     In some embodiments, the vehicle management system  65  comprises program instructions  76  configured to intentionally increase a travel time  206  of the self-driving vehicle  2  in response to the temperature detection system  110  detecting that the first temperature  184  exceeds a predetermined threshold. 
     In some embodiments, at least one of a passenger cabin  120  of the self-driving vehicle  2 , a motor compartment  122  of the self-driving vehicle  2 , a battery compartment  202  of the self-driving vehicle  2 , and a cargo compartment  124  of the self-driving vehicle  2  comprises the first portion  183 . 
     The battery compartment  202  can comprise one or more batteries  204 . A battery  204  can be housed in a battery housing  203 . The battery compartment  202  can comprise one or more battery housings  203 . In some embodiments, one battery housing  203  comprises multiple batteries  204 . In some embodiments, one battery housing  203  comprises one battery  204 . 
     In some embodiments, the batteries  204  are configured to provide electricity to a motor  218 , which can be an electric motor such as an electric motor that propels a Tesla vehicle. The motor  218  can be located in a motor compartment  122 . The motor compartment  122  can comprise one or more motors  218  configured to propel the self-driving vehicle  2 . 
     As used herein, “compartments” can be complete enclosures or partial enclosures. For example, some motor compartments  122  partially enclose a motor  218  but are partially open in an area that faces downward toward the road. 
     In some embodiments, batteries  204  are configured to provide electricity to other parts of a self-driving vehicle  2  such as spark plugs, door actuators, window actuators, computers, display screens, electronic control systems, etc. 
     In some embodiments, the motor  218  is a combustion engine. Some combustion engines use fuels such as gasoline and diesel. Some motors  218  use hydrogen or other substances as fuel. For example, some embodiments use a motor such as a motor used in a Toyota Mirai. 
     In some embodiments, the camera  10  (illustrated in  FIG.  14   ) is an infrared camera. In some embodiments, the camera  10  comprises cameras  24   a ,  24   b ,  24   c  configured to take pictures based on detecting light that is visible to the human eye. 
     The temperature detection system  110  can comprise at least one of an infrared camera, a thermocouple  116 , a resistance temperature detector  121 , a thermistor  123 , a pyrometer  126 , and a thermometer  128 . At least one of the infrared camera, the thermocouple  116 , the resistance temperature detector  121 , the thermistor  123 , the pyrometer  126 , and the thermometer  128  can be configured to detect the first temperature  184  of the first portion  183 . 
     In some embodiments, the vehicle management system  65  is configured to increase the travel time by changing from a first travel route  207  to a destination  209  chosen by a first rider  1  to a second travel route  208 . The vehicle management system  65  can be configured to change from the first travel route  207  to the second travel route  208  to intentionally increase the travel time in response to the temperature detection system  110  detecting that the first temperature  184  exceeds the predetermined threshold. 
     In some embodiments, a safety system comprises at least one processor  77  and at least one memory  75  having the program instructions  76  that when executed by the at least one processor  77  are configured to cause the vehicle management system  65  to increase the travel time of the self-driving vehicle  2  in response to the temperature detection system  110  detecting that the first temperature  184  exceeds the predetermined threshold. 
     In some embodiments, a vehicle management system  65  is configured to reduce a speed of the self-driving vehicle  2  in response to the temperature detection system  110  detecting that at least one of the first temperature  184  exceeds a predetermined temperature threshold  210  and a trajectory of the first temperature  184  exceeds a predetermined trajectory threshold  211 . 
       FIG.  24    illustrates a diagrammatic view of temperature data compared to time. For example, the temperature detection system  110  can detect temperatures of portions of the vehicle  2  at regular time intervals (e.g., every 0.1 second) or at irregular time intervals (e.g., at 1 second, at 2 seconds, at 5 seconds, and then at 7 seconds). 
       FIG.  24    comprises a temperature axis  220  and a time axis  221 . Temperature data is plotted on the graph to create a temperature data curve  222 . A temperature can exceed a temperature threshold  210   a . For example, temperature  224   c  exceeds the temperature threshold  210   a . Temperature  224   a  and temperature  224   b  do not exceed the temperature threshold  210   a.    
     Some embodiments comprise analyzing a trajectory of temperature data in addition to or instead of analyzing the temperature data compared to a temperature threshold  210   a . The curve data  222  for a temperature  224   a  at a first time comprises a first trajectory  223   a . The curve data  222  for a temperature  224   b  at a second time comprises a second trajectory  223   b.    
     In some embodiments, the trajectory is a slope of the curve data  222  at a given time. For example, the slope at temperature  224   b  at the second time is greater than the slope at temperature  224   a  at the first time. The slope at temperature  224   b  at the second time exceeds a trajectory threshold  211 , and the slope at temperature  224   a  at the first time does not exceed the trajectory threshold  211 . Program instructions  76  can be configured to cause certain actions (e.g., can cause the vehicle management system  65  to intentionally and automatically reduce the speed of the self-driving vehicle  2 ) in response to detecting that the trajectory  223   b  of the temperature  224   b  exceeds the predetermined trajectory threshold  211 . In the embodiment illustrated in  FIG.  24   , using the trajectory threshold  211  enables the safety system to take certain actions before would be possible if the program instructions  76  were configured to wait (to take the actions) until a temperature exceeds the temperature threshold  210   a.    
     Some embodiments use both the temperature threshold  210   a  and the trajectory threshold  211  to ensure a high probability of the actions being necessary before inconveniencing the rider. Some embodiments only use the temperature threshold  210   a.    
     In some embodiments, the trajectory threshold  211  is based on the program instructions  76  determining a probability of a temperature exceeding the temperature threshold  210   a  in the future. The trajectory threshold  211  can be based on a rate of temperature increase and in some cases also considers the values of the temperatures. In some embodiments, if the trajectory of the temperature curve  222  is too great, the program instructions  76  take certain actions to protect riders. The program instructions  76  can be configured to analyze the temperature data curve  222  to determine if a trajectory of the temperature data curve  222  justifies taking the actions described herein. 
     In some embodiments, a safety system comprises at least one processor  77  and at least one memory  75  having program instructions  76  that when executed by the at least one processor  77  are configured to cause the vehicle management system  65  to intentionally reduce the speed of the self-driving vehicle  2  to a velocity below a local speed limit and above five miles per hour in response to the temperature detection system  110  detecting that the first temperature  184  exceeds the predetermined temperature threshold  210 . 
     In some embodiments, a safety system comprises at least one processor  77  and at least one memory  75  having program instructions  76  that when executed by the at least one processor  77  are configured to cause the vehicle management system  65  to intentionally reduce the speed of the self-driving vehicle  2  in response to the temperature detection system  110  detecting that the trajectory of the first temperature  184  exceeds the predetermined trajectory threshold  211 . 
     In some embodiments, a temperature detection system  110  comprises at least one of an infrared camera, a thermocouple  116 , a resistance temperature detector  121 , a thermistor  123 , a pyrometer  126 , and a thermometer  128 . At least one of the infrared camera, the thermocouple  116 , the resistance temperature detector  121 , the thermistor  123 , the pyrometer  126 , and the thermometer  128  can be configured to detect the first temperature  184  of the first portion  183 . 
     In some embodiments, at least one of a passenger cabin  120  of the self-driving vehicle  2 , a motor compartment  122  of the self-driving vehicle  2 , a battery compartment  202  of the self-driving vehicle  2 , and a cargo compartment  124  of the self-driving vehicle  2  comprises the first portion  183  of the self-driving vehicle  2 . The temperature detection system  110  can comprise at least one of an infrared camera, a thermocouple  116 , a resistance temperature detector  121 , a thermistor  123 , a pyrometer  126 , and a thermometer  128 . At least one of the infrared camera, the thermocouple  116 , the resistance temperature detector  121 , the thermistor  123 , the pyrometer  126 , and the thermometer  128  can be configured to detect the first temperature  184  of the first portion  183 . 
     In some embodiments, a self-driving vehicle  2  comprises a passenger cabin  120  comprising the first portion  183 . The temperature detection system  110  can comprise an infrared camera coupled to a second portion of the self-driving vehicle  2  such that the infrared camera is configured to detect the first temperature  184  of the first portion  183  of the passenger cabin  120 . The vehicle management system  65  can comprise program instructions  76  configured to reduce the speed in response to the temperature detection system  110  detecting that the first temperature  184  exceeds the predetermined temperature threshold  210 . 
     In some embodiments, a self-driving vehicle  2  comprises a motor compartment  122  and a battery compartment  202 . At least one of the motor compartment  122  and the battery compartment  202  can comprise the first portion  183  of the self-driving vehicle  2 . The temperature detection system  110  can comprise an infrared camera coupled to a second portion of the self-driving vehicle  2  such that the infrared camera is configured to detect the first temperature  184  of the first portion  183 . The vehicle management system  65  can comprise program instructions  76  configured to reduce the speed in response to the temperature detection system  110  detecting that the first temperature  184  exceeds the predetermined temperature threshold  210 . 
     In some embodiments, a motor compartment  122  comprises an electric motor and/or a combustion motor. Combustion motors can use many different types of fuel including gasoline and diesel. A self-driving vehicle  2  can comprise a motor compartment  122 , which can comprise the first portion  183  of the self-driving vehicle  2 . 
     As used herein, a compartment comprises a portion if the portion is a part the compartment. As used herein, a compartment comprises a portion if the portion is anywhere inside the compartment, including inside an object that is inside the compartment. 
     In some embodiments, the temperature detection system  110  comprises at least one of a thermocouple  116 , a resistance temperature detector  121 , a thermistor  123 , a pyrometer  126 , and a thermometer  128 . At least one of the thermocouple  116 , the resistance temperature detector  121 , the thermistor  123 , the pyrometer  126 , and the thermometer  128  can be configured to detect the first temperature  184  of the first portion  183  of the motor compartment  122 . The vehicle management system  65  can comprise program instructions  76  configured to reduce the speed in response to at least one of the thermocouple  116 , the resistance temperature detector  121 , the thermistor  123 , the pyrometer  126 , and the thermometer  128  detecting that at least one of the first temperature  184  exceeds the predetermined temperature threshold  210  and the trajectory of the first temperature  184  exceeds the predetermined trajectory threshold  211 . 
     In some embodiments, a self-driving vehicle  2  comprises a battery compartment  202  comprising the first portion  183  of the self-driving vehicle  2 . The battery compartment  202  can comprise one or more batteries  204 . The temperature detection system  110  can comprise at least one of an infrared camera, a thermocouple  116 , a resistance temperature detector  121 , a thermistor  123 , a pyrometer  126 , and a thermometer  128 . At least one of the infrared camera, the thermocouple  116 , the resistance temperature detector  121 , the thermistor  123 , the pyrometer  126 , and the thermometer  128  can be configured to detect the first temperature  184  of the first portion  183  of the battery compartment  202 . The vehicle management system  65  can comprise program instructions  76  configured to reduce the speed in response to at least one of the infrared camera, the thermocouple  116 , the resistance temperature detector  121 , the thermistor  123 , the pyrometer  126 , and the thermometer  128  detecting that at least one of the first temperature  184  exceeds the predetermined temperature threshold  210  and the trajectory of the first temperature  184  exceeds the predetermined trajectory threshold  211 . 
     In some embodiments, a self-driving vehicle  2  comprises a battery  204  and a battery housing  203  configured to house the battery  204 . At least one of the battery  204  and the battery housing  203  can comprise the first portion  183  of the self-driving vehicle  2 . The temperature detection system  110  can comprise at least one of a thermocouple  116 , a resistance temperature detector  121 , a thermistor  123 , and a thermometer  128 . At least one of the thermocouple  116 , the resistance temperature detector  121 , the thermistor  123 , and the thermometer  128  can be coupled to at least one of the battery  204  and the battery housing  203 . At least one of the thermocouple  116 , the resistance temperature detector  121 , the thermistor  123 , and the thermometer  128  can be configured to detect the first temperature  184  of the first portion  183 . A vehicle management system  65  can comprise program instructions  76  configured to reduce the speed in response to at least one of the thermocouple  116 , the resistance temperature detector  121 , the thermistor  123 , and the thermometer  128  detecting that at least one of the first temperature  184  exceeds the predetermined temperature threshold  210  and the trajectory of the first temperature  184  exceeds the predetermined trajectory threshold  211 . 
     In some embodiments, a self-driving vehicle  2  is configured to drive a first rider  1  to a destination  209  chosen by the first rider  1 . A vehicle management system  65  can comprise at least one processor  77  and at least one memory  75 . The at least one memory  75  can comprise program instructions  76 . The at least one memory  75  can comprise at least one of a temperature threshold  210  and a trajectory threshold  211 . The program instructions  76  can be configured to cause the self-driving vehicle  2  to cease driving toward the destination  209  in response to the temperature detection system  110  detecting that at least one of the first temperature  184  exceeds the temperature threshold  210  and a trajectory of the first temperature  184  exceeds the trajectory threshold  211 . 
     In some embodiments, a temperature detection system  110  comprises at least one of an infrared camera, a thermocouple  116 , a resistance temperature detector  121 , a thermistor  123 , a pyrometer  126 , and a thermometer  128 . At least one of the infrared camera, the thermocouple  116 , the resistance temperature detector  121 , the thermistor  123 , the pyrometer  126 , and the thermometer  128  can be configured to detect the first temperature  184  of the first portion  183 . 
     In some embodiments, program instructions  76  are configured to cause the self-driving vehicle  2  to cease driving toward the destination  209  in response to the temperature detection system  110  detecting that the trajectory of the first temperature  184  exceeds the trajectory threshold  211 . 
     In some embodiments, a self-driving vehicle  2  comprises a door  130  and a door lock  132  configured to impede opening the door  130 . Program instructions  76  can be configured to cause the vehicle management system  65  to unlock the door  130  of the self-driving vehicle  2  in response to the temperature detection system  110  detecting that at least one of the first temperature  184  exceeds the temperature threshold  210  and the trajectory of the first temperature  184  exceeds the trajectory threshold  211 . 
     In some embodiments, a safety system comprises a speed detection system  134 . Program instructions  76  can be configured to cause the vehicle management system  65  to automatically unlock the door  130  in response to the temperature detection system  110  detecting that the first temperature  184  exceeds the temperature threshold  210  and the speed detection system  134  determining that the self-driving vehicle  2  has a movement speed that is less than a first speed threshold. In some embodiments, a first speed threshold can be less than fifteen miles per hour, less than five miles per hour, and/or greater than 0.2 miles per hour. 
     In some embodiments, a self-driving vehicle  2  comprises a door  130  and a motor (e.g., a door actuator  135 ) configured to open the door  130 . Program instructions  76  can be configured to cause the motor to open the door  130  in response to the temperature detection system  110  detecting that the first temperature  184  exceeds the temperature threshold  210  and the safety system detecting that the self-driving vehicle  2  has a movement speed that is less than a first speed threshold. In some embodiments, a first speed threshold is less than ten miles per hour, less than two miles per hour, and/or greater than 0.2 miles per hour. 
     In some embodiments, program instructions  76  have different modes that the program instructions  76  implement in response to a temperature detection system  110  detecting various temperatures. These modes can help protect riders from elevated temperatures. 
     A vehicle management system  65  can comprise program instructions  76  having multiple driving modes. Each driving mode can be used under specific circumstances. For example, in driving mode A, the program instructions  76  can be configured to maintain a conservative distance away from other vehicles. In driving mode B, the program instructions  76  can enable much more aggressive driving by permitting the self-driving vehicle  2  to come within a much smaller distance from other vehicles (than is the case in driving mode A). 
     While driving mode A is generally safer (and thus is generally preferable) compared to driving mode B, there are times when driving mode B is actually safer than driving mode A. For example, if the self-driving vehicle  2  is on fire, has abnormally high temperatures, and/or has temperatures that are rising very quickly, driving mode B can enable the self-driving vehicle  2  to reach an emergency services location faster than driving mode A. 
     In some embodiments, a safety system comprises a self-driving vehicle  2 . The safety system can comprise a temperature detection system  110  coupled to the self-driving vehicle  2  and configured to detect a first temperature  184  of a first portion  183  of the self-driving vehicle  2 . The safety system can comprise a vehicle management system  65  comprising program instructions  76  having a first mode  212  and a second mode  213 . The vehicle management system  65  can be configured to autonomously drive the self-driving vehicle  2 . 
     In some embodiments, a vehicle management system  65  comprises at least one memory  75  comprising at least one of a temperature threshold  210  and a trajectory threshold  211 . 
     In some embodiments, in the first mode, the safety system is configured to make the self-driving vehicle  2  available to accept a pick-up request  214  of a rider  1 . 
     In some embodiments, in the second mode, the safety system is configured to make the self-driving vehicle  2  unavailable to accept the pick-up request. 
     In some embodiments, program instructions  76  are configured to exit the first mode and enter the second mode in response to the temperature detection system  110  detecting that at least one of the first temperature  184  exceeds the temperature threshold  210  and a trajectory of the first temperature  184  exceeds the trajectory threshold  211 . 
     In some embodiments, a temperature detection system  110  comprises at least one of an infrared camera, a thermocouple  116 , a resistance temperature detector  121 , a thermistor  123 , a pyrometer  126 , and a thermometer  128 , and at least one of the infrared camera, the thermocouple  116 , the resistance temperature detector  121 , the thermistor  123 , the pyrometer  126 , and the thermometer  128  is configured to detect the first temperature  184  of the first portion  183 . 
     In some embodiments, program instructions  76  are configured to exit the first mode and enter the second mode in response to the temperature detection system  110  detecting that the trajectory of the first temperature  184  exceeds the trajectory threshold  211 . 
     In some embodiments, the safety system is configured to exit the second mode and enter the first mode in response to the temperature detection system  110  detecting that the first temperature  184  does not exceed the temperature threshold  210 . 
     In some embodiments, the safety system is configured to exit the second mode and enter the first mode in response to the temperature detection system  110  detecting that the trajectory of the first temperature  184  does not exceed the trajectory threshold  211 . 
     In some embodiments, a self-driving vehicle  2  comprises a passenger cabin  120  comprising the first portion  183 . A temperature detection system  110  can comprise an infrared camera coupled to a second portion of the self-driving vehicle  2  such that the infrared camera is configured to detect the first temperature  184  of the first portion  183  of the passenger cabin  120 . Program instructions  76  can be configured to exit the first mode and enter the second mode in response to the infrared camera detecting that the first temperature  184  of the first portion  183  of the passenger cabin  120  exceeds the temperature threshold  210 . 
     In some embodiments, a motor compartment  122  comprises an electric motor and/or a combustion motor. Combustion motors can use many different types of fuel including gasoline and diesel. In some embodiments, the combustion motor can be a Ford Raptor engine or a Toyota Tundra engine. In some embodiments, the motor can be a Toyota Prius hybrid motor system. In some embodiments, the motor can be a Tesla electric motor. 
     In some embodiments, a self-driving vehicle  2  comprises a motor compartment  122  comprising the first portion  183  of the self-driving vehicle  2 . A temperature detection system  110  can comprise at least one of an infrared camera, a thermocouple  116 , a resistance temperature detector  121 , a thermistor  123 , a pyrometer  126 , and a thermometer  128 . At least one of the infrared camera, the thermocouple  116 , the resistance temperature detector  121 , the thermistor  123 , the pyrometer  126 , and the thermometer  128  can be configured to detect the first temperature  184  of the first portion  183  of the motor compartment  122 . 
     In some embodiments, program instructions  76  are configured to exit the first mode and enter the second mode in response to at least one of the infrared camera, the thermocouple  116 , the resistance temperature detector  121 , the thermistor  123 , the pyrometer  126 , and the thermometer  128  detecting that the first temperature  184  of the first portion  183  of the motor compartment  122  exceeds the temperature threshold  210 . 
     In some embodiments, a self-driving vehicle  2  comprises a battery compartment  202  comprising the first portion  183  of the self-driving vehicle  2 . A temperature detection system  110  can comprise at least one of an infrared camera, a thermocouple  116 , a resistance temperature detector  121 , a thermistor  123 , a pyrometer  126 , and a thermometer  128 . At least one of the infrared camera, the thermocouple  116 , the resistance temperature detector  121 , the thermistor  123 , the pyrometer  126 , and the thermometer  128  can be configured to detect the first temperature  184  of the first portion  183  of the battery compartment  202 . 
     In some embodiments, program instructions  76  are configured to exit the first mode and enter the second mode in response to at least one of the infrared camera, the thermocouple  116 , the resistance temperature detector  121 , the thermistor  123 , the pyrometer  126 , and the thermometer  128  detecting that at least one of the first temperature  184  exceeds the temperature threshold  210  and the trajectory of the first temperature  184  exceeds the trajectory threshold  211 . 
     The first temperature  184  can be a temperature detected at a time in the past. For example, the first temperature  184  may have been detected three seconds ago. Once the temperature detection system  110  detects that the first temperature  184  (e.g., a number representing temperature) exceeds a threshold, the program instructions  76  can take any of the actions described herein. In other words, the program instructions  76  can detect that a temperature “exceeds” a threshold even if the temperature is a past temperature. In some embodiments, the number representing temperature is a resistance value or a voltage value. 
     In some embodiments, a safety system comprises a self-driving vehicle  2 . The safety system can comprise a temperature detection system  110  coupled to the self-driving vehicle  2  and configured to detect a first temperature  184  of a first portion  183  of the self-driving vehicle  2 . The safety system can comprise a vehicle management system  65  configured to autonomously drive the self-driving vehicle  2  and comprising program instructions  76  having a first mode  212  and a second mode  213 . 
     In some embodiments, a vehicle management system  65  comprises at least one memory  75  comprising at least one of a temperature threshold  210  and a trajectory threshold  211 . Program instructions  76  can be configured to cause the self-driving vehicle  2  to stop moving via the first mode in response to the temperature detection system  110  detecting that at least one of the first temperature  184  exceeds the temperature threshold  210  and a trajectory of the first temperature  184  exceeds the trajectory threshold  211 . Program instructions  76  can be configured to cause the self-driving vehicle  2  to stop moving via the second mode in response to the safety system detecting an indication of a person located inside the self-driving vehicle  2  and the temperature detection system  110  detecting that at least one of the first temperature  184  exceeds the temperature threshold  210  and the trajectory of the first temperature  184  exceeds the trajectory threshold  211 . 
     In some embodiments, the second mode can be configured to enable the self-driving vehicle  2  to stop more quickly than the first mode. The second mode can be configured to enable the self-driving vehicle  2  to move at a greater speed than the first mode. The vehicle management system  65  can be configured to determine a local speed limit, and the second mode can be configured to enable the self-driving vehicle  2  to exceed the local speed limit by a greater amount than the first mode. The second mode can be configured to enable the self-driving vehicle  2  to accelerate faster than the first mode (e.g., to reach a stopping location faster than would be possible in the first mode). The second mode can be configured to enable the self-driving vehicle  2  to decelerate faster than the first mode (e.g., to enable the self-driving vehicle  2  to stop more quickly than would be possible in the first mode). 
     In some embodiments, a self-driving vehicle  2  is configured to drive on a road. The vehicle management system  65  can comprise a vehicle guidance system  117  having at least one of a camera  111 , a radar  118 , and a lidar  119 . The vehicle guidance system  117  can be configured to detect objects (e.g., other cars) located outside the self-driving vehicle  2  on the road. Program instructions  76  can be configured to enable the self-driving vehicle  2  to come closer to the objects (e.g., other cars) in the second mode than in the first mode (e.g., to enable the self-driving vehicle  2  to reach a stopping location faster than would be possible in the first mode because the second mode enables changing lanes between close vehicles). 
     In some embodiments, a self-driving vehicle  2  comprises a battery compartment  202  comprising a first portion  183  of the self-driving vehicle  2 . A temperature detection system  110  can comprise at least one of an infrared camera, a thermocouple  116 , a resistance temperature detector  121 , a thermistor  123 , a pyrometer  126 , and a thermometer  128 . At least one of the infrared camera, the thermocouple  116 , the resistance temperature detector  121 , the thermistor  123 , the pyrometer  126 , and the thermometer  128  can be configured to detect the first temperature  184  of the first portion  183  of the battery compartment  202 . Program instructions  76  can be configured to cause the self-driving vehicle  2  to stop moving in response to at least one of the infrared camera, the thermocouple  116 , the resistance temperature detector  121 , the thermistor  123 , the pyrometer  126 , and the thermometer  128  detecting that at least one of the first temperature  184  exceeds the temperature threshold  210  and the trajectory of the first temperature  184  exceeds the trajectory threshold  211 . 
     In some embodiments, a self-driving vehicle  2  comprises at least one of a camera  24   a ,  24   b ,  24   c  configured to detect the indication via image recognition (e.g., using an image analysis system  70  that can use an application programming interface (“API”) called “Amazon Rekognition” from Amazon Web Services, Inc.). 
     In some embodiments, a self-driving vehicle  2  comprises an antenna  19  configured to detect the indication via receiving a radio communication from a remote computer device of the person. The remote computing device can emit radio communications, which the self-driving vehicle  2  can receive via the antenna  19 . Receiving the radio communications can notify the self-driving vehicle  2  that the rider is located in the self-driving vehicle  2 . 
     In some embodiments, a self-driving vehicle  2  comprises a seat occupancy sensory  57  configured to detect the indication. 
     In some embodiments, a self-driving vehicle  2  is configured to drive on a road. A vehicle management system  65  can comprise a vehicle guidance system  117  having at least one of a camera  111 , a radar  118 , and a lidar  119 . The vehicle guidance system  117  can be configured to detect objects located outside the self-driving vehicle  2  on the road. Program instructions  76  can comprise a third mode  216 . 
     In some embodiments, in the first mode, the program instructions  76  are configured to prompt the vehicle management system  65  to drive the self-driving vehicle  2  toward a location. 
     In some embodiments, program instructions  76  are configured to exit the first mode and enter the second mode in response to the temperature detection system  110  detecting that the first temperature  184  exceeds the temperature threshold  210  and the safety system determining that a person is not located inside the self-driving vehicle  2 . 
     In some embodiments, in the second mode, the program instructions  76  are configured to prompt the vehicle guidance system  117  to implement a first stopping mode. 
     In some embodiments, program instructions  76  are configured to exit the first mode and enter the third mode  216  in response to the temperature detection system  110  detecting that the first temperature  184  exceeds the temperature threshold  210  and the safety system determining that the person is located inside the self-driving vehicle  2 . 
     In some embodiments, in the third mode  216 , the program instructions  76  are configured to prompt the vehicle guidance system  117  to implement a second stopping mode configured to enable the self-driving vehicle  2  to come to a stop in less time than the first stopping mode. 
     In some embodiments, the second stopping mode can be configured to enable the self-driving vehicle  2  to move at a greater speed than the first stopping mode. The vehicle management system  65  can be configured to determine a local speed limit, and the second stopping mode can be configured to enable the self-driving vehicle  2  to exceed the local speed limit by a greater amount than the first stopping mode. The second stopping mode can be configured to enable the self-driving vehicle  2  to accelerate faster than the first stopping mode (e.g., to reach a stopping location faster than would be possible in the first stopping mode). The second stopping mode can be configured to enable the self-driving vehicle  2  to decelerate faster than the first stopping mode (e.g., to enable the self-driving vehicle  2  to stop more quickly than would be possible in the first stopping mode). 
     Interpretation 
     To reduce unnecessary redundancy, not every element or feature is described in the context of every embodiment, but all elements and features described in the context of any embodiment herein and/or incorporated by reference can be combined with any elements and/or features described in the context of any other embodiments. 
     The self-driving vehicle  2  can be any suitable vehicle. For example, the self-driving vehicle  2  can be a Tesla Model S made by Tesla, Inc. The Tesla Model S can include the Enhanced Autopilot package and the Full Self-Driving Capability package. The Full Self-Driving Capability package includes eight active cameras to enable full self-driving in almost all circumstances. 
     The self-driving vehicle  2  can also be a Waymo car. Waymo was formerly the Google self-driving car project. Waymo, which is owned by Alphabet Inc., has logged thousands of self-driving miles over many years. Waymo vehicles have sensors and software that are designed to detect pedestrians, cyclists, vehicles, roadwork and more from a distance of up to two football fields away in all directions. Waymo has stated that its software leverages over four million miles of real world driving data. In some embodiments, self-driving vehicles sometimes drive themselves, sometimes are driven remotely by a computer system, and sometimes are driven manually by a human turning a steering wheel, operating pedals, and performing other driver functions. In several embodiments, a self-driving vehicle drives without a human inside the vehicle to pick up the human and then lets the human drive the vehicle. Although in some cases, the human may choose not to drive the vehicle and instead may allow the vehicle to drive (e.g., steer and control speed) itself (e.g., in response to a destination requested by the human). 
     The remote computing device  12  can be a smartphone, a tablet computer, a laptop computer, a desktop computer, a server, augmented reality glasses, an implanted computer, and/or any type of computer. A rider can bring her remote computing device  12  into the self-driving vehicle  2  and then can leave the self-driving vehicle  2  with her remote computing device  12 . In some embodiments, the rider requests a ride at her home with a remote computing device  12 , but then leaves the remote computing device  12  at home when she goes to get a ride from the vehicle  2 . 
     In some embodiments, the remote computing device  12  is an iPhone made by Apple Inc. or an Android phone based on software made by Alphabet Inc. The remote computing device  12  can comprise a speaker configured to emit sounds, a microphone configured to record sounds, and a display screen configured to display images. The remote computing device  12  can comprise a battery configured to provide electrical power to operate the remote computing device  12 . 
     In some embodiments, portions of the vehicle management system  65  can be physically coupled to the self-driving vehicle  2  while other others of the vehicle management system  65  are not physically coupled to the vehicle  2  and are located remotely relative to the vehicle  2 . 
     In some embodiments, at least a portion of the vehicle management system  65  is located in the vehicle  2 . In several embodiments, at least a portion of the vehicle management system  65  is located remotely relative to the vehicle  2 . The vehicle management system  65  can comprise many servers, computers, and vehicles. The vehicle management system  65  can comprise cloud computing and cloud storage. 
     In several embodiments, the entire vehicle management system  65  is located in the self-driving vehicle  2 . The vehicle  2  can comprise the vehicle management system  65 . In some embodiments, a first portion of the vehicle management system  65  is physically coupled to the vehicle  2 , and a second portion of the vehicle management system  65  is not physically coupled to the vehicle  2 . The second portion can be located remotely relative to the vehicle  2 . In several embodiments, the entire vehicle management system  65  is located remotely relative to the vehicle  2 . 
     The phrase “communicatively coupling” can include any type of direct and/or indirect coupling between the self-driving vehicle  2 , remote computing device  12 , and vehicle management system  65 . For example, the remote computing device  12  can be communicatively coupled to the vehicle management system  65  via servers, the Cloud, the Internet, satellites, Wi-Fi networks, cellular networks, and any other suitable communication means. 
     Some of the devices, systems, embodiments, and processes use computers. Each of the routines, processes, methods, and algorithms described in the preceding sections may be embodied in, and fully or partially automated by, code modules executed by one or more computers, computer processors, or machines configured to execute computer instructions. The code modules may be stored on any type of non-transitory computer-readable storage medium or tangible computer storage device, such as hard drives, solid state memory, flash memory, optical disc, and/or the like. The processes and algorithms may be implemented partially or wholly in application-specific circuitry. The results of the disclosed processes and process steps may be stored, persistently or otherwise, in any type of non-transitory computer storage such as, e.g., volatile or non-volatile storage. 
     The term “app”, as used in this disclosure, refers to both native apps and mobile cloud apps (and Web apps). Native apps are installed directly on remote computing devices, whereby developers create separate app versions for each type of remote computing device (e.g., iPhone devices and Android devices). Native apps may be stored on the remote computing device out of the box, or the native apps can be downloaded from a public or private app store and installed on the remote computing device. Self-driving vehicle data associated with native apps can be stored on the remote computing device and/or can be stored remotely and accessed by the native app. Internet connectivity may be used by some instances of apps. Other instances of apps may not use Internet connectivity. In some embodiments, apps can function without Internet connectivity. 
     Mobile cloud apps are very similar to Web-based apps. The main similarity is that both mobile cloud apps and Web apps run on servers external to the remote computing device and may require the use of a browser on the remote computing device to display and then use the app user interface (UI). Mobile cloud apps can be native apps rebuilt to run in the mobile cloud; custom apps developed for mobile devices; or third-party apps downloaded to the cloud from external sources. Some organizations offer both a native and mobile cloud versions of their applications. In short, the term “app” refers to both native apps and mobile cloud apps. 
     None of the steps described herein is essential or indispensable. Any of the steps can be adjusted or modified. Other or additional steps can be used. Any portion of any of the steps, processes, structures, and/or devices disclosed or illustrated in one embodiment, flowchart, or example in this specification can be combined or used with or instead of any other portion of any of the steps, processes, structures, and/or devices disclosed or illustrated in a different embodiment, flowchart, or example. The embodiments and examples provided herein are not intended to be discrete and separate from each other. 
     The section headings and subheadings provided herein are nonlimiting. The section headings and subheadings do not represent or limit the full scope of the embodiments described in the sections to which the headings and subheadings pertain. For example, a section titled “Topic 1” may include embodiments that do not pertain to Topic 1 and embodiments described in other sections may apply to and be combined with embodiments described within the “Topic 1” section. 
     Some of the devices, systems, embodiments, and processes use computers. Each of the routines, processes, methods, and algorithms described in the preceding sections may be embodied in, and fully or partially automated by, code modules executed by one or more computers, computer processors, or machines configured to execute computer instructions. The code modules may be stored on any type of non-transitory computer-readable storage medium or tangible computer storage device, such as hard drives, solid state memory, flash memory, optical disc, and/or the like. The processes and algorithms may be implemented partially or wholly in application-specific circuitry. The results of the disclosed processes and process steps may be stored, persistently or otherwise, in any type of non-transitory computer storage such as, e.g., volatile or non-volatile storage. 
     The various features and processes described above may be used independently of one another, or may be combined in various ways. All possible combinations and subcombinations are intended to fall within the scope of this disclosure. In addition, certain method, event, state, or process blocks may be omitted in some implementations. The methods, steps, and processes described herein are also not limited to any particular sequence, and the blocks, steps, or states relating thereto can be performed in other sequences that are appropriate. For example, described tasks or events may be performed in an order other than the order specifically disclosed. Multiple steps may be combined in a single block or state. The example tasks or events may be performed in serial, in parallel, or in some other manner. Tasks or events may be added to or removed from the disclosed example embodiments. The example systems and components described herein may be configured differently than described. For example, elements may be added to, removed from, or rearranged compared to the disclosed example embodiments. 
     Conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular embodiment. The terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list. Conjunctive language such as the phrase “at least one of X, Y, and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be either X, Y, or Z. Thus, such conjunctive language is not generally intended to imply that certain embodiments require at least one of X, at least one of Y, and at least one of Z to each be present. 
     The term “and/or” means that “and” applies to some embodiments and “or” applies to some embodiments. Thus, A, B, and/or C can be replaced with A, B, and C written in one sentence and A, B, or C written in another sentence. A, B, and/or C means that some embodiments can include A and B, some embodiments can include A and C, some embodiments can include B and C, some embodiments can only include A, some embodiments can include only B, some embodiments can include only C, and some embodiments can include A, B, and C. The term “and/or” is used to avoid unnecessary redundancy. 
     While certain example embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions disclosed herein. Thus, nothing in the foregoing description is intended to imply that any particular feature, characteristic, step, module, or block is necessary or indispensable. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions, and changes in the form of the methods and systems described herein may be made without departing from the spirit of the inventions disclosed herein.