Patent Publication Number: US-9412270-B2

Title: Wireless vehicle detection system and associated methods having enhanced response time

Description:
RELATED APPLICATIONS 
     The present application is a continuation application which claims priority to and the benefit of U.S. Non-Provisional patent application Ser. No. 14/475,916, titled, “Wireless Vehicle Detection System and Associated Methods Having Enhanced Response Time,” filed on Sep. 3, 2014, which is a continuation of U.S. Non-Provisional patent application Ser. No. 14/194,162, titled, “Wireless Vehicle Detection System and Associated Methods Having Enhanced Response Time,” filed on Feb. 28, 2014, now U.S. Pat. No. 8,855,902, issued Oct. 7, 2014, which claims priority and benefit to provisional application No. 61/770,606, titled, “Wireless Vehicle Detection System and Associated Methods Having Enhanced Response Time,” filed on Feb. 28, 2013; application No. 61/770,789, titled, “Wireless Vehicle Detector Aggregator and Interface to Controller and Associated Methods,” filed on Feb. 28, 2013; and application No. 61/770,951, titled “Wireless Vehicle Detection System, Sensor Pods, and Associated Methods,” filed on Feb. 28, 2013, each of which is incorporated herein by reference in its entirety. This application is also related to U.S. patent application Ser. No. 14/194,280, titled “Wireless Vehicle Detector Aggregator and Interface to Controller and Associated Methods,” filed on Feb. 28, 2014, which is also incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to vehicle detection systems and, more particularly, wireless vehicle detection systems and methods associated with detecting vehicles on roadways or other travel surfaces. 
     BACKGROUND 
     Currently offered wireless detection systems are cumbersome and expensive, with various components communicating over the same RF channel, and with a relatively short RF communication range. An average sized traffic intersection, for example, requires multiple repeaters to communicate to the various in-road wireless vehicle sensors. This configuration makes the entire system expensive to install, thereby reducing the opportunities for using vehicle detection technology. 
     Moreover, current wireless vehicle detection systems use wired communication from the access point to the controller cabinet. Inside of the controller cabinet, connections are made through a detector rack using cables and multiple printed circuit boards; usually two or four per card. Connecting large numbers of detector signals can be cumbersome and costly. 
     SUMMARY OF INVENTION 
     Applicants recognized problems associate with current vehicle detection systems and methods including needs for lower cost, more reliable and easy to install, i.e. minimum lane closure time during installation, among others. Embodiments of wireless vehicle detection systems and associated methods of the present invention address these problems with eloquent solutions including, for example, a flexible vehicle detection system with a simplified architecture. Embodiments of the wireless vehicle detection systems reduce if not eliminate the need for repeaters. Embodiments of the present invention, for example, provide systems and methods having sensors able to communicate over longer distances, which allow repeaters to be eliminated for intersections, if desired, and still maintain relatively long, e.g., 10 years, battery or other power source life. Embodiments of the invention are less-costly and more accurate and robust than current systems. 
     Embodiments can include one or more wireless sensor pods having a unique antenna with its radiating element close to the surface, the antenna having a radiation pattern and orientation that allows the sensor to transmit signals more than approximately 700 feet, for example, to an access point. To conserve power usage, an embodiment of the sensor pod is adapted to detect received communication signal strength, and operationally adapted to adjust transmitting power based upon said strength. According to embodiments of the invention, the sensor pod can include, for example, a vehicle detector controller adapted to determine the presence of one or more vehicles, and a communication controller connected to the vehicle detector and adapted to transmit data 700 feet or more away from the sensor pod, the data relating to the detected presence of one or more vehicles. The vehicle detector controller and the communication controller each having separate clock cycles and separately controlled sleep cycles for drawing power according to an embodiment of the sensor pod. The sensor pod can further include, for example, a battery sufficiently large to support transmit power sufficient to achieve a transmission range of 300 feet or more and a hybrid layer capacitor connected in parallel electrically to the battery to protect the battery from degradation at transmit power levels to thereby extend the life of the battery. To fit in the enclosure of the sensor pod, embodiments of the invention include a low profile antenna of the pod positioned in a substantially horizontal orientation when positioned inside an enclosure of the sensor pod and near a top end of the enclosure when the sensor pod is positioned in or below the surface of the road, the antenna is adapted to allow for and support a 902-928 MHz ISM radio frequency band. The low profile antenna can also have an antenna housing having a hollow interior to allow communication circuitry components to be mounted at least partially inside the antenna housing thereby decreasing vertical space requirements inside of the enclosure of the sensor pod according to an embodiment of the invention. 
     Embodiments of the wireless vehicle detection system can further include, for example, a base station adapted to provide processing and storage for the wireless vehicle detection system and an access point adapted to communicate with the base station wireless at a communication frequency of approximately 2.4 GHz or via one or more wires, and further adapted to communicate with the one or more sensor pods at a communication frequency of approximately 902-928 Mhz. 
     Embodiments of the invention can be used for a plurality of traffic zones, each zone including, for example, an access point in communication with a sensor pod. Embodiments of the access point can include, for example, a sensor state aggregator module adapted to maintain current detect status of the one or more sensor pods in a respective zone, the sensor state aggregator comprising a set of instructions that causes the access point, when executed by a access point controller, to perform the operation of generating a first sensor state array, each of the one or more sensor pods in the respective zone having an entry in the sensor state array. The operations according to an embodiment of the invention can further include, for example, updating the sensor state array responsive to receiving one or more signals from the one or more sensor pods in the respective zone, the one or more signals including current detect status of the one or more sensor pods. The access point is adapted to communicate with the base station. Accordingly, embodiments of the sensor state aggregator module associated with the access point can further include, communicating, to the base station, an output message indicating a time stamp and event trigger details responsive to receiving an individual status message from one or more of the sensor pods responsive to an event trigger, and communicating the updated sensor state array indicating current detect status of the one or more sensor pods upon demand or after a predetermined time period. 
     Embodiments of the base station can be adapted to provide data processing and storage for the wireless vehicle detection system. The base station can include, for example, a base station controller, a bus interface unit emulator, and a traffic detector aggregator module adapted to aggregate data from the plurality of access points so that a user can configure and monitor the wireless vehicle detection system. An embodiment of the traffic detector aggregator module comprises a set of instructions that causes the base station, when executed by the base station controller for example, to perform the operation of generating a second sensor state array, each of the one or more sensor pods in all of the zones having an entry in the sensor state array. The operations can further include, for example, updating the second sensor state array responsive to receiving updated sensor state array from one of the plurality of access points, generating a vehicle detector array, the vehicle detector array comprising information indicating a physical detector input for each of the zones of and time stamps of event triggers, and updating the vehicle detector array responsive to receiving the output message from one of the plurality of access points. 
     Embodiments of a sensor pod provide extended communication range to allow an access point to talk to all or almost all sensors in an intersection without the need of repeaters. Embodiments of a wireless vehicle detection system provide a relatively low cost, easy to install and flexible wireless vehicle detection system and associated methods. 
     Embodiments of aggregators, controllers, systems and methods of the present invention, for example, aggregate sensor detect status at the access point and relay that information to a base station periodically by wire or wirelessly. Inside of the controller cabinet assembly, a base station unit aggregates and combines sensor status data into detector output data according to an embodiment of the invention. Additionally, the base station controller and SDLC interface circuitry can emulate bus interface units such that, for example, up to 128 detector outputs can be provided through a single SDLC cable and without need for any additional printed circuit boards or their associated special cables. 
     Embodiments of the system can include, for example, a plurality of access points adapted to communicate with one or more sensor pods in a plurality of zones, each zone having at least one sensor pod in communication with at least one of the plurality of access points. An embodiment can include, for example, a plurality of access points in a traffic intersection. Embodiments of the access point can include, for example, an access point controller including a sensor state aggregator module adapted to maintain current detect status sensor pods in a zone. The sensor state aggregator, according to an embodiment of the invention, can cause the access point to perform the operations of generating a first sensor state array, each of the one or more sensor pods in the respective zone having an entry in the sensor state array and updating the sensor state array responsive to receiving one or more signals from the one or more sensor pods in the respective zone, the one or more signals including current detect status of the one or more sensor pods. Embodiments of the invention can cause the access point to perform the operations of communicating an output message indicating a time stamp and event trigger details responsive to receiving an individual status message from one or more of the sensor pods responsive to an event trigger, and communicating the updated sensor state array indicating current detect status of the one or more sensor pods upon demand or after a predetermined time period. 
     Embodiments of the system can further include, for example, a base station adapted to provide data processing and storage for the wireless vehicle detection system. The base station can comprise a base station controller and one or more non-transitory memories encoded with one or more computer programs operable by the base station controller. The one or more computer programs, according to an embodiment of the invention, can include a traffic detector aggregator module adapted to aggregate data from the plurality of access points so that a user can configure and monitor the wireless vehicle detection system. The traffic detector aggregator module comprising, for example, a set of instructions that causes the base station, when executed by the base station controller, to perform the operation of generating a second sensor state array, each of the one or more sensor pods in all of the zones having an entry in the sensor state array, and updating the second sensor state array responsive to receiving updated sensor state array from one of the plurality of access points. The operations adapted to be performed by the base station can further include, for example, generating a vehicle detector array, the vehicle detector array comprising information indicating a physical detector input for each of the zones of and time stamps of event triggers and updating the vehicle detector array responsive to receiving the output message from one of the plurality of access points. Embodiments of the base station can further include, for example, one or more bus interface unit (BIU) emulators adapted to be in communication with a SDLC Interface, the SDLC interface being in communication with a traffic controller so that the BIU emulator is responsive to the traffic controller 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       So that the manner in which the features and advantages of the invention, as well as others, which will become apparent, may be understood in more detail, a more particular description of the invention briefly summarized above may be had by reference to the embodiments thereof, which are illustrated in the appended drawings, which form a part of this specification. It is to be noted, however, that the drawings illustrate only various embodiments of the invention and are therefore not to be considered limiting of the invention&#39;s scope, which may include other effective embodiments as well. 
         FIG. 1  illustrates an environmental view of the wireless vehicle detection system according to an embodiment of the invention. 
         FIG. 2  illustrates a schematic diagram of the wireless vehicle detection system according to an embodiment of the invention. 
         FIG. 3  illustrates an environmental view of a sensor pod installed in a road surface according to an embodiment of the invention. 
         FIG. 4  illustrates a schematic block diagram of a sensor pod according to an embodiment of the invention. 
         FIG. 5  illustrates a schematic block diagram of a vehicle detector controller according to an embodiment of the invention. 
         FIG. 6  illustrates a schematic block diagram of a communication controller according to an embodiment of the invention. 
         FIG. 7  illustrates a schematic block diagram of an access point according to an embodiment of the invention. 
         FIG. 8  illustrates the access point according to an embodiment of the invention. 
         FIG. 9  illustrates the access point housing according to an embodiment of the invention. 
         FIG. 10  illustrates the access point according to an embodiment of the invention. 
         FIG. 11  illustrates a panel antenna according to an embodiment of the invention. 
         FIG. 12  illustrates an omnidirectional antenna according to an embodiment of the invention. 
         FIG. 13  illustrates flow chart depicting operation of methods associated with a wireless detection system according to an embodiment of the invention. 
         FIG. 14  is a flow chart depicting operation of methods for asynchronous events associated with a wireless vehicle detection system according to an embodiment of the present invention. 
         FIG. 15  illustrates a block diagram of the base station according to an embodiment of the invention. 
         FIG. 16  illustrates a block diagram of the sensor state aggregator according to an embodiment of the invention. 
         FIG. 17  illustrates a block diagram of the traffic detector aggregator according to an embodiment of the invention. 
         FIG. 18  illustrates the sensor state array according to an embodiment of the invention. 
         FIG. 19  illustrates the vehicle detector array according to an embodiment of the invention. 
         FIG. 20  illustrates a graphical user interface to manage the wireless vehicle detection system according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. 
     Embodiments of the present invention include a wireless vehicle detection system having an extended range that eliminates or at least reduces the number of repeaters needed. An average sized traffic intersection using current vehicle detection systems requires multiple repeaters to communicate with current vehicle detection sensors. Embodiments of the present invention include, for example, one or more wireless sensor pods having extended range and battery life that enables the wireless vehicle detection system according to embodiments of the present invention to communicate over long distances for a number of years (e.g., five years or more) without repeaters. Embodiments of the invention provide, for example, enhanced response times and lower latency by providing sensor pods that are adapted to communicate directly with access points over long distances (e.g., 300 feet or more). Embodiments of the present invention provide a cost-effective wireless detection system for a broad range of transportation needs. 
     As illustrated in  FIG. 1 , the vehicle detection system  100  can include a plurality of wireless sensor pods  200  adapted to detect the presence of a vehicle and positioned in or below the road surface, an access point  300  mounted to a traffic pole and adapted to receive data sensed by the sensor pods, and a base station  400  positioned within a traffic controller cabinet  600  to provide data signal processing. 
     As illustrated in  FIG. 2 , embodiments of vehicle detection system  100  can include a plurality of access points  300  each adapted to communicate with one or more sensor pods  200  in a traffic region zone. According to an embodiment of present invention, each zone includes at least one sensor pod  200  in communication with one of the plurality of access points  300 . Each access point  300  is adapted to communicate with up to 130 sensor pods  200  in a zone according to an embodiment of the present invention. The base station  400  can be adapted to provide data processing and storage for the wireless vehicle detection system and be connected to a WAN or LAN network and a traffic controller  402  as understood by those skilled in the art. Embodiments of the wireless vehicle detection system  100  enable a user to configure or monitor the vehicle detection system  100  using a remote device  407 . 
       FIG. 3  illustrates a sensor pod  200  installed below a road surface. Embodiments of the sensor pod  200  can include, for example, an antenna  204  adapted to communicate with the access point  300 , a PC board  211  where one or more electronic hardware components attach thereto, a battery  206 , and a hybrid layer capacitor (HLC)  208  connected in parallel electrically to the battery  206  to protect the battery from degradation as understood by those skilled in the art. 
     Embodiment of the present invention provides for simple installation of the sensor pods  200  with minimal road closure duration. A small hole can be cut in the road using, for example, a diamond tipped drill bit or other suitable drilling or cutting apparatus as understood by those skilled in the art. According to an example embodiment, the hole is approximately two and half inches deep and four to four and half inches in diameter. After the hole is drilled, a shop vacuum can be used to remove debris and a propane torch can be used to dry out the hole before the adhesive is used. Epoxy or adhesive is placed in the bottom of the hole and the sensor pod is positioned inside the hole and in the adhesive. According to some embodiments, the remaining void of the hole is filled with adhesive or sealant and topped with a sealant  202  that is leveled with the surface of the road. A top end of the enclosure of the sensor pod  200  can be positioned such that the top surface is near the roadway surface. This allows, as illustrated in  FIG. 3  for example, for the antenna  204  positioned inside the enclosure of the sensor pod to be near the surface of the road. According to an example embodiment, the sensor pod  200  is positioned approximately ⅜ of an inch from the roadway surface. The radiation pattern of the antenna enables efficient communication with the access point  300  when the antenna  204  is positioned inside the enclosure of the pod and installed below the surface of the road according to an embodiment of the invention. 
     As illustrated in  FIG. 4 , embodiments of the sensor pod can include a vehicle detector controller  240  adapted to detect the presence of a vehicle and a communication controller  220  adapted to communicate data relating to the presence of one or more vehicles to the access point  300 . The vehicle detector controller  240  and the communication controller  220  can be connected by a serial communication link  241  such as SPI, UART, or other communication links as understood by those skilled in the art. One or more program lines  242  can also be used to connect or control the two controllers  220 ,  240 . According to an embodiment of the present invention, the vehicle detector controller  240  and the communication controller  220  each have separate clock cycles and separately controlled sleep cycles for drawing power. The battery  206  of the sensor pod is large enough to support transmit power sufficient to achieve at least 300 feet or more. In an example embodiment, the battery  206  is a lithium thionylchloride, compact D size and is capable of storing a substantial charge for several years. The battery  206  can provide power to the sensor pod  200  for up to 10 years with an average of 700 activation per hour, twenty four hours a day, every day of the week and can be replaced as needed according to an embodiment of the invention. In some embodiments, the battery life is up to 5 years. According to various embodiments of the present invention, the battery  206  is electrically connected in parallel to one or more HLC capacitors  208  to support high current operations. As understood by those skilled in the art, the HLC capacitor  208  also protects the battery  208  from degradation at transit power by reducing the load on the battery and thereby extends the life of the battery  206 . 
     An embodiment of the sensor pod  200  has the capability to transmit at a high power of approximately 20 dBm to the access point  300 . Together the communication controller  220  and vehicle detector controller  240  manage the power from the power source. The HLC capacitor  208  electrically attached in parallel to the battery allows for high current draw which supports the high power radio transmissions. One or both of the controllers  220 ,  240  are adapted to detect the signal strength of a received signal from the access point  300  and adjusting the transmitting power based upon that strength such that power is conserved, thereby lengthening battery life. An embodiment of the sensor pod  200 , for example, provides extended range features that allow the pod to communicate with the access point  300  without repeaters and with a long battery life. 
       FIG. 5  illustrates an embodiment of the vehicle detector controller  240  that is adapted to sense parameters for detecting vehicles, measuring vehicle occupancy, counting the number of detected vehicles, detecting parameters for speed calculations, and other parameters for a broad range of transportation and traffic applications. 
     An embodiment of the vehicle detector controller  240  can include, for example, a plurality of Anisotropic Magneto-Resistive based magnetic sensors  212   a - d  adapted to sense parameters of vehicles. Vehicles contain ferrous materials that disturb the uniform intensity and direction of the Earth&#39;s magnetic field. Embodiments of the sensor pods  200  may include one or more magnetic sensors  212  to detect disturbances of the Earth&#39;s magnetic field created by a vehicle (e.g., car, truck, or motorcycle). In some embodiments, one or more of the plurality of magnetic sensors  212  may act as redundant sources of vehicle detection in the event that a magnetic sensor fails. As illustrated in  FIG. 5 , the vehicle detector controller  240  may include a x-axis magnetic sensor  212   a , a y-axis magnetic sensor  212   b , and a z-axis magnetic sensor  212   c . In certain embodiments, the vehicle detector controller  240  may include two z-axis magnetic sensors  212   c ,  212   d  spaced apart in a single sensor pod to calculate the speed of a passing vehicle. The dual sensors  212   c ,  212   d  may also act as redundant sensors if one of the sensors fails to operate properly. In other embodiments the dual magnetic sensors may be two y-axis or x-axis sensors, or a combination of the x, y, or z-axis sensors. With dual placed magnetic sensors, the first magnetic sensor will experience a detection of the passing vehicle a fraction of a second before the second sensor in moving traffic. With a predetermined displacement distance between two magnetic sensors and time measurement between the two magnetic sensors, a speed computation can be made using a single sensor pod. In some embodiments, a plurality of sensor pods  200  can be placed at a predetermined displacement distance and used to calculate the speed of a passing vehicle. Speed computation can be performed by the sensor module controller  230  in the vehicle detector controller  240  or by one or more remote devices that receive data sensed by the sensor pod  200 . The sensor module controller  230  can also receive sensed data from one or more temperature  215  and vibration  216  sensors and process the sensed data to determine, for example, the presence of ice, snow, water or temperature measurements. Signal processing functions of the sensor module controller  230  may also include characterizing sensed vibrations data to facilitate the detection and classification of a vehicle. 
     The sensor module controller  230  can further be adapted to determine if one or more of the magnetic sensors  212  are operating within satisfactory limits and generate a signal or alarm if the one or more sensors are not operating satisfactory. This signal or alarm can be based on historical measured values of the sensors. The signal or alarm can be transmitted to the base station  400  or the traffic controller  402  for further action by field personnel for example. 
     Embodiments of the vehicle detector controller  240  may also include a calibration module  213  adapted to adjust for sensor offset, or to set or reset one or more of the plurality of magnetic sensors  212 . The vehicle detector controller  240  may also utilize one or more power control devices such as MOSFETs  231  to intermittently supply power to different circuitry components including the plurality of magnetic sensors  212 . According to an embodiment of the present invention, the output of the plurality of magnetic sensors  212  is routed through a differential multiplexer  214  and then passed to a fast respond differential amplifier  217 . The output of the amplifier  217  is routed to the sensor module controller  230 , which is adapted to perform signal processing according to an embodiment of the invention. 
     The sensor module controller  230  can process sensed data to determine, for example, the presence of a vehicle, count the number of detected vehicles, and the speed of passing vehicles. In some embodiments, the sensor module controller  230  gathers the sensed data from the magnetic sensors  212  and transmits the data for the base station  400 , or traffic controller  402  to process the sensed data and determine the presence of a vehicle and other traffic parameters. The sensor module controller  230  can further include an analog to digital converter to convert the signal received from the differential amplifier  217  to digital info ration. The sensor module controller  230  can be further adapted to communicate with the communication controller  220 , which is adapted to relay information to and from the access point  300 . 
     As illustrated in  FIG. 6 , the communication controller  220  can include one or more of a radio transceiver  222 , an antenna  204 , a serial memory  205 , a communication module controller  210  and a MOSFET  231  or other power control device. According to an embodiment of the present invention, the communication controller  220  is adapted to receive signals from the vehicle detector controller  240  and generate a packet suitable to be wirelessly transmitted to the access point  300 . The communication controller  220  can also perform overhead functions for the sensor pod  200  including, for example, the timing and synchronization of communicating data signals, and data formatting. One or more of the foregoing functions can be performed by the communication module controller  210  according an embodiment of the present invention. The communication module controller  210  can also receive sensed data from one or more temperature  215  and vibration  216  sensor and process the sensed data to determine, for example, the presence of ice, snow, water or temperature measurements. A serial memory  205 , as understood by those skilled in the art, can also be used to facilitate remote firmware upgrades to the sensor pods  200 . The memory, according to an embodiment, is non-transitory and may store one or more computer programs to be executed by the communication module controller  210  or the sensor module controller  230  for example. 
     The radio transceiver  222  of the communication controller  220  is configured to communicate in the 902-928 Mhz ISM band according to an embodiment of the invention. In other embodiments, the radio transceiver  222  is configured to communicate in the 433-435 MHz ISM band, or both the 433-435 MHz and the 902-928 Mhz ISM band for example. An operating frequency in the 902-928 Mhz ISM or 433-434 MHz ISM band provides a greater communication range than the operating frequency of 2.4 Ghz, for example because the 2.4-2.5 Ghz ISB band typically has greater pass losses. Also, the airways of the 2.4-2.5 Ghz ISB band are more crowded than the 902-928 Mhz ISB because the 2.4-2.5 Ghz ISB band includes RF signals from common devices such as Wi-Fi hubs, and Bluetooth devices. A communication frequency of no more than 928 Mhz provides sufficiently low attenuation communication and range at the available power for the sensor pods according to embodiments of the invention. Although exemplary embodiments of the sensor pods  200  include one or more radio transceivers  222  adapted to operate at a frequency at or less than 928 Mhz, a 2.4 Ghz operating frequency is suitable for some components of the wireless vehicle system such as the radio communication between the base station  400  and the access point  300 . 
     Antenna size is inversely proportional to the frequency and therefore, as understood by those skilled in the art, the size of an antenna operating at 900 Mhz is typically larger than an antenna operating at 2.4 Ghz. Embodiments of the sensor pod  200  can include an antenna  204  adapted to fit inside the enclosure of the sensor pod. The antenna  204  can be low profile and adapted to be positioned in a substantially horizontal orientation when positioned inside the enclosure of the sensor pod, as illustrated in  FIG. 3  for example. The low profile antenna  204  can also have an antenna housing having a hollow interior to allow communication circuitry components to be mounted at least partially inside the antenna housing thereby decreasing vertical space requirements inside the enclosure of the sensor pod. In some embodiments the antenna  204  is a low profile loop antenna or a low profile patch antenna as understood by those skilled in the art. 
     Embodiments of the sensor pod  200  can include a non-transitory memory having an executable program stored thereon to manage the power of the sensor pod.  FIG. 13  illustrates an example embodiment of the instruction of a program loop executed by the sensor pod to manage power of the sensor pod. Both the vehicle detector and communication controllers  220 ,  240  spend most of the time in a power-saving sleep mode. Power management methods of embodiments of the invention enable the sensor pod  200  to run for a number years without replacing the battery. The program loop instructions illustrated in  FIG. 13  can be implemented on both the vehicle detector controller  240  and the communication controller  220  individually and in combination. In step  802 , for example, the sensor pod will go into a low power sleep mode  802  for a predetermined amount of time. When the sensor pod wakes up, in step  804 , for example, the controller executes the next function and then schedules a subsequent function in the chain to be executed in step  806  for example. According to an embodiment of the present invention, there is always one pending event or function to be executed by the sensor pod. 
       FIG. 14  example embodiment of the instruction of a program loop executed by the sensor pod to manage power of the sensor pod for an asynchronous event being triggered on the communication controller  220  as understood by those skilled in the art. In step  902 , for example, the sensor pod will go into a low power sleep mode for a predetermined amount of time or until an event is triggered. When an event is triggered  904 , the sensor pod wakes up from the low power sleep mode and executes the asynchronous event in step  906 , and schedules a subsequent function in the chain to be executed in step  912 . If an event is not triggered, such as in step  910 , the pod remains sleep for a predetermined amount of time and then wakes up and executes the next function scheduled to be executed in step  910  and then schedules a subsequent function in the chain to be executed in step  912 , for example. The above mentioned program loop implements an asynchronous event driven system for an embodiment of the wireless vehicle detection system and associated methods. 
       FIG. 7  illustrates a block diagram of an embodiment of an access point  300  that is adapted to communicate with a plurality of sensor pods  200  and a base station  400 . A single access point  300  can communicate with up to 130 sensor pods according to an embodiment of the present invention. The wireless vehicle detection system can include the use of a plurality of access points  300  at a traffic intersection. As user of the wireless vehicle detector system can map zones to include one or more sensor pods and an access point  300 . Embodiments of the access point  300  may include a plurality of radio controllers  304  adapted to communicate with sensor pods  200  at an operating frequency of approximately 900 Mhz, and one or more base station communication controllers  312  adapted to facilitate communication with the base station  400  at an operating frequency at approximately 2.4 Ghz using an antenna  305 . Each radio controller  304  can talk to multiple sensor pods  200  using a low-power randomized-time-of-transmission TDMA protocol. The access point  300  can communicate with the base station by wire or wirelessly. According to an embodiment of the access point  300 , a Zigbee radio module  312 , as understood by those skilled in the art, is used to communicate wirelessly to the base station  400  and an RS-485 link, as understood by those skilled in the art, is used for wired communication. According to certain embodiments, all of the radio controllers  304  that are in communication with the sensor pods  200  are kept synchronized by the access point module controller  310 . Synchronization allows the radio controllers to schedule transmission in the same time slots. This way, transmitting radios do not overload adjacent radio receivers. The access point module controller  310  is adapted to collect data from the plurality of radio controllers  304 , aggregate the data, and transmit the data the base station  400  located in the traffic controller cabinet according to an embodiment of the invention. 
     Embodiments of the access point  300  may include one or more antennas  301 ,  303 , positioned remotely from an access point housing  302  as illustrated in  FIGS. 8 and 10 , for example. The one or more antennas  301 ,  303  are adapted to be in communication with the plurality of sensor pods  200  and further adapted to communicate with the access point housing  302 , which in turn communicates with the base station  400 . 
     According to an embodiment of the present invention, the antenna can be an omnidirectional antenna  301 , as understood by those skilled in the art, mounted to a traffic pole or mass arm at and within approximately 300 feet of the plurality of sensor pods  200  and at the operating frequency of approximately 900 Mhz.  FIG. 12  illustrates the omnidirectional antenna  301  according to an embodiment of the invention. For traffic intersections that may require the sensor pods  200  to be approximately 300-700 feet from the access point  300 , a combination of an omnidirectional antenna  301  and panel antennas  303  can be used as illustrated in  FIG. 10  for example. In an example embodiment, the panel antennas  303  can communicate with the sensor pods  200  positioned 300-700 feet away and the omnidirectional antenna  301  can communicate with the sensor pods  200  positioned within 300 feet. 
     As illustrated in  FIG. 11 , according to an embodiment of the invention, the panel antenna  303  is a directional antenna with two panel antennas mounted a predetermined distance between each other and a pole positioned there between. One or more RF cables can be used to communicate data between the antennas  303 ,  301  and the access point housing  302 .  FIG. 9  illustrates an embodiment of the access point housing  302  according to an embodiment of the invention. 
     When selecting a mounting location for the access point  300 , factors to be considered may include the elevation needed for RF communications, the line of sight to the traffic controller cabinet  600 , the distance from the wireless sensor pods  200 , and the accessibly of the mounted access point to field support personnel using a lift truck. The antennas  301 ,  303  can be mounted approximately 15-30 feet above ground, for example, on a traffic pole or mast arm and adjacent to the access point housing  302 . The access point housing  302  can be placed in the line of site and close to the traffic controller cabinet  600  that houses the base station  400  according to an embodiment of the invention. When the access point and base station are communicating wirelessly, the access point  300  can receive approximately 120 VAC from an interface panel in the traffic controller cabinet  600  through a power cable connected there between. In other embodiments, the access point  300  receives power using the RS-485 link that is used for wired communication between the access point  300  and the base station  400 . 
     Each traffic region can utilize one or more sensor pods that make up a zone. Each zone uses an access point  300  that is in communication with one or more sensor pods  200  according to an embodiment of the invention. The zones and sensors can be mapped using a graphical user interface (GUI), such as illustrated in  FIG. 20  for example. The base station  400  automatically detects the presences of sensors  200  and the GUI can be viewed on a remote device  407  to facilitate the mapping of the sensors according to an embodiment of the invention. The interface can be viewed using a web browser and can illustrate, for example, a sensor tree that illustrates the organization of sensors, and details of individual sensors. As understood by those skilled in the art, such sensor details can include, for example, a sensor name, unique id, sensor description, the current mode, read right frequency, battery level, vehicle sample frequency, sensitivity, and detect timeout. 
     In an embodiment of the invention, sensor information and processed sensor data can be viewed using the GUI using data processed by the base station  400 . The base station  400  has the computing power of an advance transportation controller (ATC), as understood by those skilled in the art, and is adapted to provide data processing and storage of data for a plurality of sensor pods in a plurality of zones according to an embodiment of the invention. The base station can be connected to a LAN or a WAN. In some embodiments, one or more web services are used on private networks to provide access to information relating to the wireless vehicle detector system  100 . 
     As illustrated in  FIG. 15 , an embodiment of the base station  400  can include a base station controller  602 , a base station communication controller  604 , an antenna  616  adapted to communicate in the 2.4-2.5 Ghz ISB band, and a synchronous data link control (SDLC) interface  614  as understood by those skilled in the art. The SDLC interface  614  can be used to connect to a traffic controller  402 . Embodiments of the invention include, for example, Bus Interface Units (BIU) to emulate detector to the traffic controller  402 . The base station communication controller  604  can be adapted to facilitate communication with a plurality of access points  300 . The base station controller  602  can include, for example, a traffic detector aggregator  610 , detector outputs  612 , and one or more BIU emulators  608 . According to an embodiment, the base station is positioned near the top of the traffic controller cabinet  600  and an AC power cord is used to provide power between the base station  400  and an interface panel in the cabinet  600  as understood by those skilled in the art. 
     The base station can also include one or more non-transitory memories encoded with one or more computer programs operable by the base station controller  602  according to an embodiment of the invention. The base station can perform signal processing functions for the plurality of sensors  200  in the wireless vehicle detection system  100 . For example, according to an embodiment of the invention, the base station  400  can execute one or more computer programs to analyze and interpret sensed data for counting the number of vehicles, occupancy, perform speed calculation, and other roadway conditions. 
       FIGS. 16 and 7  illustrate an embodiment of the sensor state aggregator  316  on or associated with an access point module controller  310 . The sensor state aggregator  316  maintains a sensor state array  360  in which each attached sensor pod  200  has an entry. These entries for sensor pods contain the current detect status for each sensor in a zone. According to an embodiment of the invention, every message  351  sent by a sensor pod to the access point  300  contains the current detect status. Using this status, the sensor state array  360  is updated with every message received and sent to the base station periodically or upon demand. All of the individual status messages  361  are transferred to the base station and may be responsive to an event trigger. The individual status messages  361  typically include a time stamp associated with the status change. 
     Embodiments of the invention can include, for example, a sensor state aggregator  316  comprising a set of instructions that cause the access point  300  to perform the operations when the instructions are executed by the access point module controller  310 , for example. The operations of the sensor state aggregator  316  associated with the access point can include, for example, generating a first sensor state array  360 , each of the one or more sensor pods  200  in the respective zone having an entry in the sensor state array. The operations of the sensor state aggregator  316  can further include, for example, updating the sensor state array  360  responsive to receiving one or more signals from the one or more sensor pods  200  in the respective zone, the one or more signals including current detect status of the one or more sensor pods, and communicating an output message indicating a time stamp and event trigger details responsive to receiving an individual status message  361  from one or more of the sensor pods responsive to an event trigger. The operations of the sensor state aggregator  316  can further include, for example, communicating the updated sensor state array indicating current detect status of the one or more sensor pods to the base station upon demand or periodically. 
       FIG. 17  illustrates an overview of a traffic detector aggregator  610  on or associated with the base station  400  according to embodiments of the present invention. The base station  400  receives the sensor state array message  362 , and individual sensor messages  361  from the access point. Based on the type of message, it is parsed and routed differently as understood by those skilled in the art. According to an embodiment of the invention, every message from sensor pod contains its detect status bit, but only the dedicated detect status messages  360  contains the time stamp for the event as will be understood by those skilled in the art. The base station also maintains a sensor state array  370  (see e.g.,  FIG. 18 ) that is similar to the sensor state array  360  associated with the access point  300 . The sensor state array  370  associated with the base station, in some embodiments, includes information indicating the current detect status for all of the sensors  200  in the plurality of zones. The traffic detector aggregator  610  can also maintain a vehicle detector array  380 , which maintains the status of numerous, e.g., 64, physical detector inputs, along with a 16 bit time stamp of when the status changed last time.  FIG. 19  illustrates an embodiment of the vehicle detector array  380 . According to an embodiment of the vehicle detector array  380 , the vehicle detector array maintains the detector inputs and the time stamp information for a plurality of sensors in a plurality of zones. 
     Embodiments of the invention can include, for example, a traffic detector aggregator  610  comprising a set of instructions that cause the base station  400  to perform the operations when the instructions are executed by the base station controller  602 , for example. The instructions of the traffic detector aggregator  610  associated with the base station is adapted to aggregate data from the plurality of access points in the plurality of zones so that a user can configure and monitor the wireless vehicle detection system  100  according to an embodiment of the invention. The traffic detector aggregator  610  can include, for example, a set of instructions that cause the base station  400  to perform operations such as, generating a sensor state array  370  associated with the base station  400 , each of the one or more sensor pods in all of the zones having an entry in the sensor state array  370 . Embodiments of the invention can further include operations such as updating the sensor state array  370  responsive to receiving updated sensor state array  360  from one of the plurality of access points  300 . Embodiments of the invention can also include, for example, generating a vehicle detector array  380  comprising information indicating a physical detector input for each of the zones of and time stamps of event triggers, and updating the vehicle detector array  380  responsive to receiving the output message from one of the plurality of access points  300 . 
     The sensor state arrays, traffic detector aggregator, and vehicle detector array maintained by the base station  400  and the access point  300  can be implemented and maintained by electronic hardware, software, or a combination of the two as understood by those skilled in the art. 
     According to an embodiment, each zone is assigned a physical detector bit in the vehicle detector array  380  and each BIU  608  is mapped to 16 physical detector inputs. In an example embodiment, physical detector bits  1 - 16  are controlled by BIU1,  17 - 32  are controlled by BIU2, and so on. According to an embodiment, a base station can emulate BIU&#39;s 1 to 4, in other embodiments it can emulate BIU&#39;s 1 to 8 as understood by those skilled in the art. According to an embodiment, the vehicle detector array  380  is updated with every message received from every sensor pod in all of the zones and the physical detector status is changed based on the user configured zone mapping. When the base station emulates a BIU  608 , it is adapted to respond to a request from the traffic controller on the SDLC interface  614  as understood by those skilled in the art. The traffic controller can act as a master and requests data from the BIU periodically. 
     An embodiment of a method to aggregate sensor data associated with an access point in a wireless vehicle detection system, for example, can include maintaining accurate detect status, volume and occupancy data if communication to base station is interrupted so that accuracy of data is not reduced by momentary disruptions or delays in communication to base station  400  and packing communication data for greater transfer efficiency. Together, these characteristics, among others, allow for the use of a low-cost RF link, such as Zigbee. Use of a wireless communication link between the access point  300  and the base station  400  is more convenient and less costly to install than a wired link in many cases. Aggregation and combination of the sensor data into detect states for input to the controller  602  at the base station  400 , for example, allows for combination of individual sensor states and data to be combined in different ways to generate intelligent vehicle detection inputs and allows data to be formatted in different ways to support multiple interface methods to the controller. As understood by those skilled in the art, emulation of one or multiple BIUs  608 , for example, allows for a simple and flexible way to transfer detection states to the controller and allows use of a pre-existing, standard interface (such as NEMA TS2) which, in turn, allows for ease of installation and configuration (e.g., only one serial cable connection is needed). As appreciated by those skilled in the art, embodiments of the present invention allow for configurable single or multiple BIUs accommodating different equipment configurations in the cabinet assembly without additional hardware assemblies, adapters, or multiple cables. 
     In the various embodiments of the invention described herein, a person having ordinary skill in the art will recognize that various types of memory are readable by a computer such as the memory described herein in reference to the various computers and servers, e.g., computer, computer server, web server, or other computers with embodiments of the present invention. Examples of computer readable media include but are not limited to: nonvolatile, hard-coded type media such as read only memories (ROMs), CD-ROMs, and DVD-ROMs, or erasable, electrically programmable read only memories (EEPROMs), recordable type media such as floppy disks, hard disk drives, CD-R/RWs, DVD-RAMS, DVD-R/RWs, DVD+R/RWs, flash drives, memory sticks, and other newer types of memories, and transmission type media such as digital and analog communication links. For example, such media can include operating instructions, as well as instructions related to the system and the method steps described above and can operate on a computer. It will be understood by those skilled in the art that such media can be at other locations instead of, or in addition to, the locations described to store computer program products, e.g., including software thereon. It will be understood by those skilled in the art that the various software modules or electronic components described above can be implemented and maintained by electronic hardware, software, or a combination of the two, and that such embodiments are contemplated by embodiments of the present invention. 
     The present application is a continuation application which claims priority to and the benefit of U.S. Non-Provisional patent application Ser. No. 14/475,916, titled, “Wireless Vehicle Detection System and Associated Methods Having Enhanced Response Time,” filed on Sep. 3, 2014, which is a continuation of U.S. Non-Provisional patent application Ser. No. 14/194,162, titled, “Wireless Vehicle Detection System and Associated Methods Having Enhanced Response Time,” filed on Feb. 28, 2014, now U.S. Pat. No. 8,855,902, issued Oct. 7, 2014, which claims priority and benefit to provisional application No. 61/770,606, titled, “Wireless Vehicle Detection System and Associated Methods Having Enhanced Response Time,” filed on Feb. 28, 2013; application No. 61/770,789, titled, “Wireless Vehicle Detector Aggregator and Interface to Controller and Associated Methods,” filed on Feb. 28, 2013; and application No. 61/770,951, titled “Wireless Vehicle Detection System, Sensor Pods, and Associated Methods,” filed on Feb. 28, 2013, each of which is incorporated herein by reference in its entirety. This application is also related to U.S. patent application Ser. No. 14/194,280, titled “Wireless Vehicle Detector Aggregator and Interface to Controller and Associated Methods,” filed on Feb. 28, 2014, which is also incorporated herein by reference in its entirety. 
     In the drawings and specification, there have been disclosed embodiments of the invention, and although specific terms are employed, the terms are used in a descriptive sense only and not for purposes of limitation. The invention has been described in considerable detail with specific reference to these illustrated embodiments. It will be apparent, however, that various modifications and changes can be made within the spirit and scope of the invention as described in the foregoing specification, and such modifications and changes are to be considered equivalents and part of this disclosure.