Patent Publication Number: US-2022234631-A1

Title: Coupling between moving cars of a transportation system

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to transportation systems, and particularly to methods and systems for coupling between moving cars of non-stop transportation systems. 
     BACKGROUND OF THE INVENTION 
     Various types of techniques for connecting between cars of transportation systems have been described in the patent literature. 
     For example, U.S. Patent Application Publication 2016/0274591 describes a vehicle combination and a method for forming and operating a vehicle combination that includes at least first and second autonomous vehicles. Each of the autonomous vehicles is configured to automatically control its motions in a state wherein the first and second autonomous vehicles do not form the vehicle combination. When the vehicle combination is formed, the two autonomous vehicles are connected via a communications connection and the first autonomous vehicle automatically controls the motion of the second autonomous vehicle via the communication connection. 
     U.S. Pat. No. 5,312,007 describes a slackless railcar coupler assembly, which is mountable in a railcar center sill, has a draft mar subassembly operable against a rear stop, and a slackfree coupler apparatus mounted in a coupler pocket forward of said draft gear subassembly. 
     SUMMARY OF THE INVENTION 
     An embodiment of the present invention that is described herein provides a coupling assembly in a first car configured to move relative to a second car, the coupling assembly includes an extender and a connector. While the first and second cars are both in motion, the extender is configured to extend away from the first car for connecting with the second car. The connector is coupled to the extender and is configured to perform the following while the first and second cars are both in motion: (i) connect with a mating connector of the second car when connecting between the first and second cars, and (ii) disconnect from the mating connector when disconnecting the first car from the second car. 
     In some embodiments, the extender includes a telescopic extender (TE). In other embodiments, the extender is configured to extend away from the first car and the connector is configured to connect with the mating connector when the first and second cars are separated from one another by a first distance, and after connecting between the connector and the mating connector and while the first and second cars are both in motion, the extender is configured to at least partially collapse toward the first car for positioning the first car at a second distance from the second car, smaller than the first distance. In yet other embodiments, at least one of the first and second cars includes a transportation equipment selected from a list consisting of: a bus, an intercity train, a light train, a suburban rail, an underground train, a boat, an automobile, a truck, a ship, an aircraft and a drone. 
     In an embodiment, the coupling assembly includes a first local control unit (LCU) coupled to the first car, and a second LCU coupled to the second car, the first and second LCUs include (i) one or more sensors, (ii) one or more communication devices, and (iii) a processor, configured to receive signals from the sensors and the communication devices, and based on the received signals, to control connection and disconnection between the first car and the second car. In another embodiment, the signals include at least first and second signals, and the processor is configured, in response to receiving the first signal, to control the extender to extend away from the first car, and in response to receiving the second signal, to control the extender to collapse toward the first car. In yet another embodiment, the processor is configured to control one or more parameters selected from a list consisting of (a) speed, (b) acceleration and deceleration, (c) a distance between the first and second cars, (d) a distance to a nearest station, (e) a distance to a hazard, and (f) braking capabilities. In an embodiment, the extender is configured to collapse toward the first car for disconnecting from the second car. 
     In some embodiments, the one or more sensors are configured to sense one or more physical parameters selected from a list consisting of (a) speed, (b) acceleration and deceleration, (c) a distance between the first and second cars, and (d) a distance to a hazard. In other embodiments, the first LCU includes a first communication device and the second LCU includes a second communication device, and, (a) when the connector and the mating connector are disconnected, the first and second communication devices are configured to exchange the signals wirelessly, and (b) when the connector and the mating connector are connected, the first and second communication devices are configured to exchange at least some of the signals over a wired connection, in yet other embodiments, the coupling assembly includes a first set of one or more first cars and a second set of one or more second cars, the first and second sets of cars are moving along a route, and the first and second LCUs are configured to control: (a) a connection between the first and second sets at a first section of the route, and (b) a disconnection between the first and second sets at a second section of the route. 
     In an embodiment, the first and second cars are disconnected from one another and are moving along a route such that the first car is a leading car and the second car is following the first car, and, in response to detecting a hazard along the route, the first and second LCUs are configured to coordinate deceleration of the first and second cars. In another embodiment, the second LCU is configured to control the second car to decelerate, and subsequently, the first LCU is configured to control the first car to decelerate. In yet another embodiment, the extender is configured to damp an impact occurring when connecting between the first car and the second car. 
     There is additionally provided, in accordance with an embodiment of the present invention, a method for coupling a first car moving relative to a second car, the method includes, while the first and second cars are both in motion and are separated from one another by a given distance: extending away from the first car, an extender for connecting with the second car, and a connector coupled to the extender and a mating connector of the second car are connected to one another. 
     The present invention will be more fully understood from the following detailed description of the embodiments thereof, taken together with the drawings in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic, pictorial illustration of a system for transporting objects without stopping, in accordance with an embodiment of the present invention; 
         FIG. 2  is a diagram that schematically illustrates a process for connecting two moving cars of a transportation system, in accordance with an embodiment of the present invention; 
         FIGS. 3A, 3B and 3C  are schematic, sectional views of three respective positions of connectors used for dynamically connecting two or more moving cars of a transportation system, in accordance with an embodiment of the present invention; and 
         FIG. 4  is a flow chart that schematically illustrates a method for dynamically connecting two or more moving cars of a transportation system, in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Overview 
     Embodiments of the present invention that are described hereinbelow provide methods and systems for connecting between two or more moving cars, also referred to herein as dynamic coupling. 
     In some embodiments, a first car, which is configured to move at a given speed relative to a second car, has a coupling assembly comprising an extender, such as but not limited to a telescopic extender (TB), and a connector (CN) coupled to the TE. While the first and second cars are both in motion, and are located at a predefined distance from one another, the FE is configured to extend away from the first car for connecting with the second car, or with a coupling assembly thereof. 
     In some embodiments, while the first and second moving cars are located within the predefined distance from one another, the CN of the first car is configured to connect with a mating CN of the second car. In some embodiments, after connecting between the CNs, the TE is configured to collapse toward the first car for coupling between the first and second cars. In other embodiments, after connecting between the CNs, the TE may remain extended without collapsing, or may partially collapse. 
     In some embodiments, the connected CNs have a latching or locking; mechanism so that after coupling therebetween, the first and second cars constitute two coupled cars of a train or any other suitable type of vehicle. 
     Note that the predefined distance is determined, inter alia, by the extension size of the TE. In some embodiments, the second car may also have a coupling assembly similar to that of the first car, so that the predefined distance may be increased by extending a TE of the second car. Moreover, the predefined distance may be controlled by setting the amount of extension in the TE of each car. 
     In some embodiments, each of the first and second cars may have one or more sensors, configured to sense, for the respective car, one or more of the following parameters: (a) speed, (b) acceleration and deceleration, and (c) distance between the first and second cars. Each car may also have a communication device, which is configured to transmit and receive signals indicative of the sensed parameters. For example, the communication device of the first car may transmit a signal indicative of the parameters sensed in the first car, to the communication device of the second car, and receive, from the communication device of the second car, another signal indicative of the parameters sensed in the second car. 
     In some embodiments, at least the first car (and typically both cars) may have a processor, which is configured, in response to receiving a first signal, to control the TE to extend away from the first car, and in response to receiving a second signal, to control the TE to collapse toward the first car. The processor of at least one of the cars is configured to disconnect between the first and second cars by extending the TE away from the first car, followed by disconnecting between the CNs, and subsequently, collapsing the TE toward the first car. During the disconnection process, the processor is configured to control various parameters, such as but not limited to relative speed and distance between the first and second cars. 
     In some cases, the first and second cars are moving along a route, such that the first car is a leading car and the second car is following the first car but is not mechanically connected to the first car. In some embodiments, a sensor of the first car may detect a hazard along the route, and the communication device of the first car may transmit, to the communication device of the second car, an alert signal indicative of the detected hazard. 
     In some embodiments, in response to receiving the alert signal, the first and second processors are configured to coordinate a deceleration of the first and second cars. In such embodiments, the processor of the second car is configured to control a deceleration of the second car, and subsequently, the processor of the first car is configured to control a deceleration of the first car, such that a safety margin is maintained between the first and second cars. Moreover, after the deceleration of both cars, the processors are configured to control any suitable relative speed between the first and second cars, e.g., maintaining the same level of relative speed controlled before detecting the hazard. 
     In other embodiments, in case an emergency stop is required due to the detected hazard, in response to receiving the alert signal, the first and second processors are configured to coordinate an emergency stop of the first and second cars. For example, when the second car follows the first car, the processor of the second car is configured to control an emergency stop of the second car, and subsequently, the processor of the first car is configured to control an emergency stop of the first car, such that the safety margin is maintained between the first and second cars. 
     In alternative embodiments, at least the first car may comprise an extender other than the telescopic extender (TE) described above. The extender may be extended and/or collapsed using any suitable mechanical mechanism, which is powered mechanically and/or electrically and/or pneumatically, and/or using any suitable combination thereof. Moreover, any other suitable type of extender may be used, instead of or in addition to at least one of the aforementioned TEs. 
     The disclosed techniques are not limited to trains. In some embodiments, the transportation system may comprise any other type of transportation vehicle, such as but not limited to a bus, an intercity train, a light train, a suburban rail, an underground train, metropolitan trains, a boat, an automobile, a truck and an aircraft. Moreover, the transportation system may transport any suitable types of objects, e.g., passengers, parcels, cargo and/or freight or any suitable combination thereof. 
     The disclosed techniques improve the efficiency of transportation systems by enabling connecting and disconnecting between at least two moving cars, so as to reduce the commuting time of passengers and other objects, connecting two trains to reduce headways (the term headway refers to safety distance required from each car and/or train), and therefore, use more cars in a given transportation line for improving line capacity. Moreover, the disclosed techniques improve efficiency of connecting trains in staging yards. The term staging yards refers to side tracks of route  33 , used for connecting between cars. 
     System Description 
       FIG. 1  is a schematic, pictorial illustration of a system  10  for transporting objects without stopping, in accordance with an embodiment of the present invention. In some embodiments, system  10  comprises a vehicle  11  having one or more cars. In the present example, vehicle  11  comprises a train having cars  12 ,  14  and  16  coupled to one another and arranged in a column along a track, referred to herein as a route  33 . 
     In some embodiments, vehicle  11  is configured to move, in direction  44  along route  33  having one or more stations (e.g., stations  22 ,  24 ,  29  and  30 ), without stopping at any of the aforementioned stations. Moreover, vehicle  11  continuously moves along route  33 , typically at a predefined speed, without changing its velocity when passing by a station or when moving between stations. The speed of vehicle  11  may be constant along route  33 , or may change to a desired speed in accordance with the administrative requirements of system  10 . 
     In the example of  FIG. 1 , route  33  appears to be circular. In other embodiments, route  33  may have any other suitable shape and/or configuration, such as but not limited to a linear shape (e.g., north to south), a curved shape, and/or two routes crossing one another. 
     In some embodiments, system  10  comprises one or more cars, such as cars  18 ,  26 ,  27  and  28 , each of which is configured to load an object (e.g., a passenger) from a station and to move for integrating with vehicle  11 . 
     In the example shown in  FIG. 1 , car  18  loads passengers from station  22  and, when vehicle  11  is located at a predefined distance from station  22 , car  18  starts moving along route  33  in direction  44 . In such embodiments, car  18  accelerates after departing from station  22  and system  10  is configured to match the speed of vehicle  11  and car  18  when making a physical contact therebetween. 
     In other words, car  18  departs from station  22  before vehicle  11  passes by station  22 , e.g., when vehicle  11  is located at the aforementioned predefined distance from station  22 . Subsequently, car  18  accelerates, for a predefined time interval, so as to obtain approximately the speed of vehicle  11 . During the predefined time interval, vehicle  11  that moves at a speed higher than that of car  18 , reduces the distance therebetween. At the end of the predefined time interval, vehicle  11  makes physical contact with car  18  when the speeds of car  18  and vehicle  11  are approximately matched. Subsequently, vehicle  11  and car  18  are making a dynamic coupling therebetween so that car  18  is integrated into vehicle  11  and constitutes the front car thereof. 
     In the context of the present disclosure and in the claims, the terms “about” or “approximately” for any numerical values or ranges indicate a suitable dimensional tolerance that allows the part or collection of components, or a physical parameters such as speed and time, to function for its intended purpose as described herein. More specifically, “about” or “approximately” may refer to the range of values ±20% of the recited value, e.g. “about 90%” may refer to the range of values from 71% to 99%. 
     In some embodiments, at least one of (and typically all of) the cars of system  10  is configured to detach from vehicle  11  (when vehicle  11  moves) and to decelerate for a given time interval from a respective station, so as to obtain a full stop at the respective station for unloading another object (e.g., another passenger). 
     In the example shown in  FIG. 1 , when vehicle approaches station  22 , car  20  detaches from vehicle  11  and decelerates so as to stop at station  22  and to unload passengers at station  22  when vehicle  11  continues moving at a desired speed and integrates with car  18  as described above. 
     In some embodiments, car  20 , which is the unloading car, is positioned at the rear of vehicle  11 . Moreover, after integrating with vehicle  11 , car  18  constitutes the front car of vehicle  11  as described above. 
     In the example of  FIG. 1 , only one car (e.g., car  18 ) loads passengers from station  22 , and only one car (e.g., car  20 ) unloads passengers at station  22 . In other embodiments, at least one of the loading and unloading cars may comprise any suitable number of cars. For example, in case station  22  is a central station of a metropolis, when a large volume of passengers arrives in station  22  (e.g., in morning trains), the unloading car (e.g., car  20 ) may comprise multiple cars. Similarly, when a large volume of passengers depart from station  22  (e.g., in afternoon and evening trains), the loading car (e.g., car  18 ) may comprise multiple cars. 
     In some embodiments, car  26  is loading passengers at station  24 , and starts moving along route  33  in direction  44  when vehicle  11  is positioned (while moving) at a predefined distance from station  24 . Note that after integrating with vehicle  11 , car  26  is the front car of vehicle  11  and car  18  will become the second car of vehicle  11 . 
     In such embodiments, the position of one or more cars of vehicle  11  within vehicle  11 , is changing along route  33 . For example, between stations  30  and  22  car  12  is at the front position and car  20  is at the rear position, and when approaching station  22 , car  20  detaches from vehicle  11  and car  16  turns into the rear car of vehicle  11 . Similarly, between stations  22  and  24 , car  18  is at the front position and car  16  is at the rear position, and when approaching station  24 , car  16  may detach from vehicle  11  and car  14  may turn into the rear car of vehicle  11 . 
     Note that in some cases vehicle  11  may pass by a given station without detaching one or more cars, and/or without integrating with a car loading passengers from the given station. In an embodiment, car  16  may not detach from vehicle  11  between stations  22  and  24 , and may remain the rear car having a different destination, e.g., station  29 . In this embodiment, vehicle  11  may integrate with car  26  between stations  24  and  29  and may have five cars (e.g., cars  26 ,  18 ,  12 ,  14  and  16 ) before detaching from car  16  when approaching station  29 . 
     In some embodiments, a passenger typically boards an origin car that, after the integration, is located at the front of vehicle  11 . During the ride the passenger moves within vehicle  11  in a direction  77  (opposite to direction  44 ), toward a destination car that is located at the rear of vehicle  11 . For example, a passenger traveling from an origin station (e.g., station  28 ) to a destination station (e.g., station  22 ), may board car  12  at station  28  and walk (or he moved using any suitable technique) along vehicle  11  to car  20 , so as to de-board at station  22 . In case the destination station of the passenger is station  29 , he or she may walk from car  12  to car  14 , which is designated to stop at station  29  and de-board from car  14 . Note that moving passengers, within vehicle  11  in direction  77 , prevents crowding and passengers congestion, and therefore, improves the mobility and flow of the passengers within vehicle  11 . 
     In accordance with the embodiments described above, for a typical passenger each car is a direct car to its destination station. In the context of the present invention and in the claims, the term “direct car” refers to the fact that once boarding an origin car at the origin station, a given passenger moves along vehicle  11  to its destination car and typically stops only at its destination station. In other words, the given passenger does not waste time due to a stop at any station located between the origin and destination stations, because vehicle  11  constantly moves. Therefore, from the passenger perspective, after boarding, the destination car stop only at the destination station. Moreover, a passenger sits at his or her destination car until the car is detached from vehicle  11  and stops at the destination station, while typically vehicle  11  has not changed its original (e.g, cruising) speed since departure from the origin station. 
     Typically, when accessing a station of system  10 , a passenger does not have to wait for a specific car and can take the next car. In some embodiments, system  10  is configured to route the cars and vehicles to transport the passenger to its destination station using various techniques described below. Moreover, due to the direct car and non-stop vehicles, the transportation is faster and the passenger spends less time commuting. 
     In some embodiments, in case the destination car is not yet coupled to vehicle  11 , the passengers may await at one of the cars of vehicle  11 , for a notice that their destination car is integrated with vehicle  11  and is available for them. In such embodiments, a passenger may (a) remain in the origin car that has a destination station that matches the passenger&#39;s destination station, or (b) move to the destination car that has not yet been integrated with vehicle  11 . Note that in scenario (a), the passenger will not move in direction  77 , and simply de-board the same car at the destination station. 
     Signage within Elements of the Transportation System 
     In some embodiments, system  10  comprises at least the following elements: vehicles having one or more cars, cars not connected to vehicles, and the aforementioned stations located along route  33 . In some embodiments, system  10  has signs for assisting the passengers in reaching their destination in the most effective manner. In some embodiments, digital (electronic) signs are positioned (a) in every station, (b) in every car, and (c) the passengers may have a handheld device, such as a smartphone or a head-mounted display (HMD), which is connected to a control sub-system of system  10  and displays information regarding the schedule and destination of each car of system  10 . 
     In some embodiments, each station has signs indicative of the departure and arrival times of cars at the station, and optionally on departures and arrivals of cars at other stations of system  10 . In the example of  FIG. 1 , the signs of station  22  may display the arrival time of car  20  and the departure of car  20  that will be integrated with the next vehicle (not shown) following vehicle  11 . Similarly, the signs of station  24  may display (a) the departure time of car  26 , and in case car  16  is scheduled to detach from vehicle  11  and to stop at station  24 , the signs will display (b) the arrival time of car  16 . Note that the signs of each station may also display information regarding other stations along route  33  and the destination of each car currently integrated in vehicle  11 . 
     In some embodiments, each car has a sign that marks the destination station thereof. The sign may also comprise a mapping of all the cars of system  10 , which are lit according to coupling and destination station. Such signs provide the passengers with information on the destinations of all cars currently integrated in vehicle  11 . Thus, each passenger knows his or her destination car in order to reach the respective destination station. 
     In some embodiments, the signage of each car displays the car status (e.g., coupling status, origin and destination), the position of each car within vehicle  11 , and whether or not passengers can move from the respective car toward their destination car of vehicle  11 . For example, when car  18  departs from station  22 , but is not yet safely coupled to vehicle as shown in  FIG. 1 , the signage displays that passengers of car  18  cannot move toward the rear of vehicle  11 . Similarly, before car  20  detaches from vehicle  11 , the signage of cars  12 ,  14  and  16  display the remaining time for safely passing to car  20 . At a predefined time interval (e.g., ten seconds) before detaching car  20 , the signage of cars  12 ,  14  and  16  may indicate that car  20  is no longer available for the present passengers of vehicle  11 . Moreover, the signage of car  20  may have a count-down display for the arrival of car  20  in station  22 . 
     In some embodiments, the signage may display the status and destination of each car of system  10 , or of some of the cars of system  10 . In the context of the present invention, the term “status” may refer to at least one of (a) whether the car moves or stops, (b) whether the car (i) loads passengers, or (ii) unloads passengers, or (iii) in idle or mode (e.g., for technical maintenance, or cleaning). For example, a moving car may be highlighted, and displays its corresponding destination. 
     In such embodiments, a car that is positioned at a given station, and therefore is not moving, may have a corresponding indication of its status as described above, and a sign indicative of its destination that may be displayed at all stations, cars and personal displays. Moreover, the signage may provide users with an indication of whether or not each car is dynamically coupled to a respective vehicle. In the example of  FIG. 1 , the signage will indicate that cars  12 ,  14  and  16  are dynamically coupled to one another, whereas cars IS and  20  are moving but are not coupled to any car of vehicle  11 . 
     In some embodiments, the signage may be carried out using color-coding, letters, lit and unlit, characters, or any other suitable marking indicative of the status of the respective car. Additionally, each car may have the destination thereof shown on the outer surface of the car so that passengers at the respective stations will be able to see the destination of the respective car. 
     In some embodiments, passengers having a personal displaying device, such as but not limited to the aforementioned smartphone or HMD, may have all the information described above displayed on the personal device. In such embodiments, the personal device may provide the user with the destination of the car he or she is currently located in, and may further provide the user with the position of its destination car and the estimated arrival time of the destination car at the destination station. 
     This particular configurations of the signage of system  10  are described by way of example, in order to enhance the performance and ease-of-use of system  10 . Embodiments of the present invention, however, are by no means limited to this specific sort of example signage configurations, and the principles described herein may similarly be applied to other sorts of signage in system  10  or in any other types of transportation systems. 
     Control Sub-System of the Transportation System 
     In some embodiments, system  10  comprises the aforementioned control sub-system. In an embodiment, the control sub-system may be centralized, referred to herein as a central control unit (CCU). In another embodiment, the control sub-system may be distributed, referred to herein as a distributed control unit (DCU). For example, a DCU may be positioned at the large stations of system  10  that are distributed along route  33  and/or as local-control units (LCUs) coupled to at least some of the aforementioned cars of system  10 , as will be described in detail in  FIG. 2  below. 
     The embodiments below are described for the CCU, but are also applicable to the DCU. 
     In some embodiments, the CCU may comprise various types of sensors, communication devices, controllers and processors (described in detail below), which are configured to accurately assess the position, speed and acceleration of each car in real-time. 
     In some embodiments, based on the sensed and communication signals, a processor of the CCU is configured to estimate and/or specify various parameters related to components (e.g., each car and vehicle) of system  10 . The processor is configured to control (a) speed, (b) acceleration and deceleration, (c) a distance between adjacent car or vehicle, (d) a distance to and/or from a nearest station, (e) a distance to a closest obstacle or hazard, (f) status of each car, such as but not limited to detaching from a vehicle, integrating with a vehicle, awaiting at a station, (g) status of the vehicle, e.g., number of cars and motors integrated in the vehicle, and (h) braking capabilities. 
     In the context of the present disclosure and in the claims, the term “braking capability” refers to at least one of (i) reducing the power applied to a motor (e.g., electrical, diesel) driving the respective car, and (ii) applying a mechanical braking assembly (e.g., friction-based) for stopping the respective car. Both braking capabilities are affected by various parameters, such as but not limited to (a) total weight of the car, (b) materials of the mechanical braking assembly, (c) number of mechanical braking actuators used (e.g., not bypassed) in the braking assembly, (d) latency period for activating a braking actuator (e.g., building a pressure in braking pistons), and (e) temperature of the braking environment and of elements of the mechanical braking assembly. 
     In some embodiments, the CCU is configured for signaling and controlling the components speed, acceleration and for commanding coupling and/or de-coupling between at least two cars and between a car and a vehicle. 
     The CCU is further configured to command cars and/or vehicles to abort coupling and/or decoupling processes when required. As will be described in detail below, one or more of the control sub-systems (e.g., CCU, and/or in stations, and/or in cars) are configured to control the cars and stations for maintaining a safety distance between adjacent components (e.g., cars). In other words, based on the signals received from at least one of the sensors and the communication devices the control sub-system is configured to specify the configuration of at least one of the vehicle (e.g., vehicle  11 ) and one or more of the aforementioned cars of system  10 . 
     Typically, the control sub-system comprises a general-purpose computer having at least a processor and/or a controller, which is programmed in software to carry out the functions described herein. The software may be downloaded to the computer in electronic form, over a network, for example, or it may, alternatively or additionally, be provided and/or stored on non-transitory tangible media, such as magnetic, optical, or electronic memory. 
     Additional embodiments related to the control sub-systems and components thereof in the stations and the cars of system  10  are described in detail below. 
     In the context of the present disclosure and in the claims, the terms “integrate with” and “couple to” are used interchangeably, the terms “detach” and “decouple” are used interchangeably, the terms “loading” and “boarding” are used interchangeably, and the terms “de-boarding” and “unloading” are used interchangeably. 
     Addressing Specific Scenarios and Requirements of the Transportation System 
     In some cases vehicle  11  may have less cars than number of stations. In some embodiments, one or more given cars of vehicle  11  may have respective destination stations, but also intermediate destination stations. In such embodiments, the passengers will wait in the given car they boarded until the car of their destination is picked up later, and then pass to their destination car at the front of vehicle  11 . 
     In some embodiments, system  10  is configured to manage connection of passengers between different routes having at least one common station. For example, a passenger departing from Pittsburgh, Pa. with a destination station at Richmond, Va., will wait at a given car dropped-off at the Baltimore station, and the given car will be integrated with the vehicle coming from New York using the same techniques described above for car  18  and vehicle  11 . After the integration, the passenger may walk to the destination car intended to stop at Richmond as its destination station. 
     In order to avoid passengers moving in direction  44  towards the front of vehicle  11 , an alternative embodiment of system  10  is possible in cases where destination car is unavailable due to a short vehicle  11 . In this embodiment, the passengers remain in an “intermediate car” but may not de-board from the intermediate car even though the intermediate car is detached from vehicle  11  and stops at a station, because the intermediate car will integrate with a subsequent vehicle (other than vehicle  11 ). After the integration with the subsequent vehicle, the passengers will move towards the back of the subsequent vehicle, to the destination car of their destination. 
     In some embodiments, the cars constituting vehicle  11  may be concatenated or split to allow better utilization of the shared vehicles. Because the passengers typically sit in their destination car before the splitting, the passengers do not move while vehicle  11  is being split, thus avoiding safety events. In such embodiments, when accessing a station (e.g., by foot), each passenger may relate to the car awaiting at the platform as his or her next car, assuming that all cars and vehicles that are sharing the same line are concatenated and/or split as needed. These embodiments are applicable for all passengers because each vehicle that passes through a station can arrive to all possible stations by concatenating and splitting. 
     In some embodiments, a vehicle having a first set of cars of system  10 , such as vehicle  11 , is configured to merge with another vehicle having a second set of cars, and/or to split into multiple sub-vehicles. In such embodiments, when a vehicle splits into two or more sub-vehicles, at a splitting point, the rear-most-sub-vehicle (also referred to herein as the second set of cars), reduces its speed to a predefined speed, so as to have a safety distance and to allow the one or more front sub-vehicles (also referred to herein as the first set of cars) to leave the splitting point. 
     In some embodiments, after obtaining the safety distance, the one or more front sub- vehicles and the rear-most-sub-vehicle are routed, each, by the CCU of system  10  to their respective routes, and the rear-most-sub-vehicle restores its original or planned speed. 
     Similarly, when merging two vehicles into a merged vehicle, at the merging point, the speeds are matched and the coupling is carried out in a like manner to the aforementioned dynamic coupling between a single car and a vehicle using the techniques described above. 
     In some embodiments, safety is obtained using a transition mechanism, which allows both cars (the rear and the front) to know, with sufficiently-high accuracy and confidence level, the actual distance and speed difference during the entire coupling process between adjacent cars and thereafter. 
     In some embodiments, in case of a communication-loss event during the dynamic coupling, the rear car (or the rear-most-sub-vehicle) stops immediately and the front car (or vehicle) also stops but after a time interval (depending on the position and speed of the cars), and at a lower deceleration rate, so as to maintain a safety distance therebetween. In other words, in case of a communication-loss event during dynamic coupling of front and rear cars, the front car will always move faster than the rear car so as to prevent a collision and to obtain a safety distance therebetween. 
     In some embodiments, each car of system  10  is configured to use the same communication and synchronization techniques in case of a need for an emergency stop at a given car. In such embodiments, the vehicle may start decelerating and/or stopping, and send a signal to the car in front of it that it can start decelerating and/or stopping at a slightly lower rate than the vehicle (e.g., vehicle  11 ), in order to maintain the safe distance between the vehicle and the front car. 
     In other embodiments, the same emergency stop technique may be applied to any car within vehicle  11  or to any other vehicle. For example, in a vehicle comprising three cars, referred to herein as a front car, a middle car, and a rear car, which may have an uncontrolled fire event in the middle car. After evacuating the passengers from the burning middle car, the front car decouples from the burning middle car and moves at the fastest speed from among the three cars. In such embodiments, the burning middle car moves at a speed slower than that of the front car, and the rear car, which is also decoupled from the burning middle car, moves at the slowest speed from among the three cars. In such embodiments, the CCU may control a diversion apparatus in route  33  to divert the burning car to a suitable different route and to stop the burning car for extinguishing the fire and other types of emergency activities at a designated safety area. 
     Using Short Vehicles for Short-Distance Transportation 
     In some cases, the distance between two or more adjacent stations may be short due to high density of passengers or goods distributed within a short section of the route. For example, in a metropolis (for passengers and parcels) and in a seaport or airport (for large cargo and/or freight) there are typically multiple short distances between adjacent station. In such cases, a passenger boarding the front car may have to rush to his or her destination car, and in some cases, the passenger may not be able to reach the destination car on time. 
     In some embodiments, the control sub-system of system  10  is configured to specify the number of cars in vehicle  11 , e.g., based on the distance between at least two adjacent stations of route  33 . 
     In some embodiments, system  10  may comprise a combination of (a) long vehicles for long distances between adjacent stations as described above, and (b) shorter vehicles (e.g., having less cars) for serving sections of a route having short distances between adjacent stations. For example, a shorter vehicle may comprise two or three cars, so that a passenger have to move only one or two cars during the ride between two adjacent stations, and therefore, may not have a problem to get to his or her destination car on time. Note that both the long and short vehicles are not stopping at stations of the metropolis, but are detaching from and coupling to cars before and after the stations, respectively. 
     In other embodiments, system  10  may comprise a combination of vehicles that are not stopping, referred to herein as non-stop vehicles such as vehicle  11 , and “traditional vehicles” that stop at predefined stations for loading and unloading objects (e.g., passengers or parcels). For example, system  10  may comprise three non-stop vehicles, such as vehicle  11 , and one traditional vehicle. In such embodiments, the first and second non-stop vehicles (e.g., arriving from stations out of the metropolis) may only detach cars at given stations so that passengers may have enough time for being at their destination cars well before the destination car detaches from the respective vehicle. 
     Subsequently, the traditional vehicle may load passengers at the given stations and transport them to their destination within the metropolis. Finally, the third non-stop vehicle may couple to cars loading passengers from the given stations and/or other stations, for transporting these passengers to stations located at distances long-enough that provide passengers with enough time to reach their destination car on time. Note that at least one of the three non-stop cars may both load and unload passengers at predefined stations. For example, a first non-stop vehicle may only detach cars, a second non-stop vehicle may detach from and integrate with cars, and a third non-stop vehicle may only integrate with cars. 
     In yet other embodiments, system  10  may comprise only non-stop vehicles that may move fast between metropolises and slower within the metropolises so as to provide the passengers with enough time to safely reach their destination cars before the detachment. Additionally or alternatively, system  10  may dynamically adjust the speed of the non-stop vehicles based on information received from the ticketing system. Note that the speed adjustment is limited so as to maintain the original schedule of the loading and unloading at the stations of system  10 . 
     In other embodiments, system  10  may comprise two cars, denoted cars “A” and “B,” and a single station. In such embodiments, car “A” loads passengers from the station and integrates with car B, and when approaching the station, car “B” detaches from car “A” and unloads passengers at the station. This minimal configuration may be used, for example, for improving the utilization of an attraction in an amusement park, or for any other suitable application for transporting passengers and/or goods. 
     Dynamic Car Planning for Transporting a Large Number of Objects To and From Stations 
     In case of a large event, such as a football match or a big concert, a large number of passengers is expected to board at a first station, and another large number of passengers is expected to de-board at another station. 
     In some embodiments, the control sub-system of system  10  is configured to receive information from the ticketing system, and based on the information, to specify and/or adjust the number of cars at the first station, in response to the unusual number of passengers. For example, a first non-stop vehicle may detach, in the first station before the large amount of passengers are boarding, three cars instead of one. Subsequently, a subsequent second non-stop vehicle, may integrate with the three cars having the large amount of passengers returning from the event, and detach the three cars at the second station so as to unload at least some of the passengers returning from the event, at their destination station. 
     Note that in case the ticketing system receives bookings for more than one destination stations, the second non-stop vehicle may detach two of the cars at the second station and the remaining additional cars at the third station. These embodiments are also applicable for rush hours in crowded areas, such as a metropolis (for passengers and/or parcels) and a port (for cargo and/or freight). 
     In alternative embodiments, based on the information received from the ticketing system indicative of unusually large number of objects at the first station, the control sub-system is configured to specify (e.g., limit) the number of tickets for the second non-stop vehicle and the remaining passengers may be permitted to board a subsequent third non-stop vehicle. 
     In other embodiments, vehicle  11  and the cars of system  10  may comprise any other suitable type of transportation equipment, such as but not limited to a bus, an intercity train, a light train, a suburban rail, an underground train, a boat, an automobile, a truck, and a cargo and/or freight carrier (e.g., a train, a truck or a ship). In yet other embodiments, vehicle  11  may comprise an aircraft (e.g., a drone) configured to carry passengers and/or parcels along a predefined route, and the cars may comprise smaller drones configured to load and unload the passengers and/or parcels between the aircraft and the stations. 
     In alternative embodiments, vehicle  11  is configured to stop for coupling to and/or for detaching cars. These embodiments may be useful in case the dynamic coupling and detaching is too complicated and/or risky. This operational mode reduces some of the benefits for passengers, and may result in a long delay to passengers that plan to de-board at intermediate stations and longer overall cycle time of route  33 . 
     In other embodiments, vehicle  11  may slow down before stations so that the dynamic coupling and decoupling (or detaching) may be carried out at lower speed. For example, if the cruising speed of vehicle  11  between stations is about 400 km per hour (KPH), the speed may decline to about 100 KPH before the dynamic coupling and/or decoupling. In other embodiments, this intermediate concept may be applied using any other suitable operational mode subject to the type of transportation as described above. For example, the speed acceleration and deceleration may differ between an intercity train and a suburban rail, and between transportation of passengers and cargo and/or freight. 
     This particular configuration of system  10  is shown by way of example, in order to illustrate certain problems that are addressed by embodiments of the present invention and to demonstrate the application of these embodiments in enhancing the performance of such a transportation system. Embodiments of the present invention, however, are by no means limited to this specific sort of example system, and the principles described herein may similarly be applied to other sorts of transportation systems. 
     Using a Coupling Assembly for Connecting Multiple Cars of the Transportation System 
       FIG. 2  is a diagram that schematically illustrates a process for connecting two moving cars  12  and  18  of system  10 , in accordance with an embodiment of the present invention. Note that the following embodiments described below for cars  12  and  18  are applicable for all the cars of system  10 , and that at least one of cars  12  and  18  may be coupled to additional cars, as described in  FIG. 1  above. 
     In some embodiments, cars  12  and  18  comprise, each, a local-control unit (LCU)  54 , which is part of the distributed control unit (DCU) described in  FIG. 1  above. Reference is now made to an inset  50 . In some embodiments, LCU  54  comprises one or more sensors  56 , which are configured to sense several physical parameters of the respective car. For example, sensors  56  of car  12  may sense speed, acceleration and deceleration of car  12 , a distance between cars  12  and  18  as shown in the steps of  FIG. 2 , and a distance to a hazard. Note that in the example of  FIG. 2 , sensors  56  are shown as a box in LCU  54 , but each of the aforementioned sensors  56  may be fitted at any suitable position of car  12  (and one or more other cars of system  10 ). For example, sensors  56  for measuring the distance between car  12  and an adjacent car, may be fitted at positions  58  and  59  of car  12 . In this example, the sensor at position  58  is configured to measure the distance between cars  12  and  18 . 
     In some embodiments, LCU  54  comprises one or more communication devices  57 , which are configured to exchange signals indicative of the aforementioned measured parameters, instructions received from any processing unit of system  10 , and any other suitable information. In some embodiments, LCU  54  comprises a processor  55 , which is configured to receive, via electrical conductors  51  (e.g, cables, wires, leads, traces) or wirelessly, signals indicative of the parameters sensed by sensors  56  and information received from communication devices  57 . 
     In some embodiments, based on the signals received from sensors  56  and communication devices  57 , processor  55  of car  12  is configured to control (a) motion parameters of car  12 , (b) coupling and decoupling procedures between car  12  and adjacent cars, as will be described in detail herein, and any other operations of car  12  and optionally of other cars of system  10 . In the context of the present disclosure and in the claims, the term “motion parameters” refers to speed, acceleration, deceleration, braking, changing course, and any other suitable parameters related to the motion of the respective cars of system  10  (e.g., cars  12  and  18 ). 
     In some embodiments, LCU  54  may comprise electrical conductors  52 , configured to exchange signals directly between sensors  56  and communication devices  57 . This configuration may be useful, for example, for controlling both cars  12  and  18  using a single processor  55  that serves as a master processor. In the example of  FIG. 2 , processor  55  of car  18  may serve as a master processor that may receive the parameters sensed by sensors  56  of car  12 , and may control, for example, the motion parameters of both cars  18  and  12 . Note that when coupling or decoupling between two cars, processor  55  of the front car is typically defined as the master processor and processor  55  of the rear car is defined as the slave processor. In the example of  FIG. 2 , cars  12  and  18  are moving in direction  44 , so that processor  55  of car  18  is defined as the master processor. In this example, processor  55  of car  18  controls the distance between cars  12  and  18 , so that in case of emergency during a coupling process between cars  12  and  18 , processor  55  of car  18  controls car  12  to reduce speed (or even stop) before changing the speed of car  18 , so as to prevent a collision between cars  18  and  12 . Embodiments related to the operation of LCUs  54  are described in detail in a section denoted “additional embodiments and variations” of the present disclosure. In other embodiments, both processors  55  of cars  12  and  18  may be slaves to a third party master processor, as described in detail herein. Additionally or alternatively, after defining an outline (e.g., predefined, or by a temporary master processor), both processors  55  of cars  12  and  18  may be local masters of their respective car. In alternative embodiments, processor  55  of the rear car (e.g., car  12 ) may serve as the master processor of both cars  12  and  18 . 
     In the context of the present disclosure and in the claims, the terms “rear car,” “trailer car” and “trailing car” are used interchangeably, and refer to the car that is not at the front (in direction  44 ) from among the cars being coupled or decoupled. In the example of  FIG. 2 , car  12  serves as the rear/trailing car. Similarly, the terms “front car” and “leading car” are used interchangeably and refer to car  18  in the example of  FIG. 2 . 
     In some embodiments, the aforementioned signals may be transmitted from and received by communication devices  57 , via electrical conductors  51  and  52 , and via any suitable type of wireless signals  53 . In such embodiments, communication devices  57  of cars  12  and  18  are configured to exchange at least some of the signals described above, so as to control the motion parameters of cars  12  and  18 . Additionally or alternatively, both processors  55  of cars  12  and  18  may be slaves to a third party master processor, located for example at the aforementioned controlled sub-system (e.g., CCU) of system  10  or at any other location. In this configuration, both communication devices  57  of cars  12  and  18  may send data to the third party master processor, and processors  55  of cars  12  and  18  may receive instructions from the third party master processor. In an embodiment, in case of communication loss with the third party master processor, one of processors  55  (e.g., the processor of car  18 , which is the front car) may be assigned as a temporary master processor, until the communication channel with the third party master processor has been recovered. 
     Reference is now made back to the general view of  FIG. 2 . In some embodiments, car  12  comprises a coupling assembly (CA)  100 , which is coupled to car  12  at a location  90 . Similarly, car  18  comprises a (CA)  101 , which is coupled to car  18  at a location  91 , and may have a configuration substantially identical to that of CA  100  described herein. In the example of  FIGS. 1 and 2 , cars  12  and  18  are moving along route  33  in direction  44 , so that location  90  is positioned at the front side of car  12 , and location  91  is positioned at the rear side of car  18 . Additionally or alternatively, at least one car of system  10  (and typically all cars) may have one or more CAs positioned at other locations. In the example of car  12 , CA  100  may be positioned at another location of car  12 , and additional CAs may be mounted on car  12  at any suitable locations other than  90  and  92 . 
     In some embodiments, all cars of system  10  may have CAs coupled at both front and rear locations thereof. For example, car  12  may have an additional CA (not shown) coupled at location  92 , so that car  12  may be coupled with an additional car, such as car  14  as shown in  FIG. 1  above. 
     In some embodiments, CA  100  comprises a telescopic extender (TE)  88 , so that while at least car  12  is in motion, TE  88  is configured to extend away from car  12  for connecting with car  18 . In some embodiments. CA.  100  comprises a connector (CN)  99 , which is coupled at the distal end of TE  88 , but in other embodiments, CN  99  may be coupled at any other suitable position of TE  88 . 
     In some embodiments, CA  101  comprises a TE  87  having the same features of TE  88 . For example, while at least car  18  is moving, TE  87  is configured to extend away from car  18  (e.g., toward CA  100  in car  12 ). CA  101  comprises a CN  98 , which is typically (but not necessarily) positioned at the distal end of TE  87  and having the same features of CN  99 . In some embodiments, CN  99  is configured to connect with a mating connector, such as CN  98 , for connecting between cars  12  and  18 . In the example configuration shown in  FIG. 2 , CAs  100  and  101  and controlled by processors  55  of cars  12  and  18 , respectively. In other embodiments, CAs  100  and  101  may be controlled by a local controller, or by a master processor (e.g., processor  55  of car  18  or a remote master, such as the third party master) as described above. 
     In some embodiments, TEs  87  and  88  are configured, each, to be extended up to a predefined distance, e.g., between zero and five meters. The amount of extension depends on the safety requirements of the particular type of vehicle and cars. For example, the extension of each TE in a train may be about two, or three or four meters (or any other suitable size), whereas the extension in an automobile may be about one meter or less (or any other suitable size). The specified predefined distance may be determined, inter alia, based on the momentum (e.g., weight and/or speed) of the car, communication time delay, and the braking ability (e.g., deceleration rate, and/or distance the car is passing from receiving a stop command, time and distance to full stop). 
     As described in  FIG. 1  above, car  18  loads passengers from station  22  and, when car  12  of vehicle  11  is located at a predefined distance from station  22 , car  18  starts moving along route  33  in direction  44 . 
     At an acceleration step  102 , car  18  accelerates for a predefined time interval, so as to obtain approximately the speed of car  12 . Note that at step  102  cars  12  and  18  are both moving and are separated from one another by a distance  112 . Note that at step  102 , TEs  88  and  87  are both in a collapsed and remain within cars  12  and  18 , respectively. 
     At a first extension step  104 , when car  18  still accelerates during the predefined time interval, car  12  moves at a speed higher than that of car  18 , and thereby, is separated from car  18  at a distance  114 , smaller than distance  112  of step  102  above. When cars  12  and  18  are separated from one another by distance  114 , TEs  88  and  87  are getting started to extend toward one another. At a second extension step  106 , both cars  12  and  16  are moving, but car  12  still moves at a speed higher than that of car  18 , and therefore, is separated from car  18  at a distance  116 , smaller than distance  114  of step  104  above. When cars  12  and  18  are separated from one another by distance  116 , at least one of TEs  88  and  87  may continue to extend toward the other TE for making physical contact between CNs  99  and  98 . For example, both TEs  88  and  87  may extend, or only one TE (e.g., TE  88 ) may extend while TE  87  may remain collapsed. Note that when one TE remains collapsed, the distance for coupling may be shortened (e.g., by half). In some embodiments, CNs  99  and  98  are connecting with one another at the end of step  106 , embodiments related to the connecting process between CNs  99  and  98  is described in detail in  FIGS. 3A-3C  below. In other embodiments, at least one of TEs  87  and  88  may start extending only when both cars  12  and  18  are moving at the same speed, and at least one of cars  12  and  18  may accelerate or decelerate to accommodate for the required approximation between cars  12  and  18 . 
     In some embodiments, TEs  88  and  87  may be used as dampers, configured to compensate for any variation in the relative speed between cars  12  and  18 . TEs  88  and  87  may be used as hard dampers, for example, by pushing against car  12 , which is over-approaching toward car  18 , and thereby, maintain distance  116  at step  106 . Additionally or alternatively, TEs  88  and  87  may be used as soft dampers. For example, in case car  12  is over-approaching toward car  18 , processor  55  is configured to control at least one of TEs  88  and  87  to slightly collapse, while adjusting the relative speed between cars  12  and  18 , and to extend after adjusting the relative speed and maintaining the specified distance between cars  12  and  18 . 
     At a cars approaching step  108 , after CNs  99  and  98  are connected with one another, cars  12  and  18  are moving closer to one another for being separated from one another by a distance  118 , smaller than distance  116  of step  106  above. In some embodiments, TE  88  is configured to collapse toward car  12 : (a) when cars  12  and  18  are getting closer to one another, or (b) when car  12  and  18  are disconnecting from one another. In other embodiments, TE  88  may remain folly or partially extended when car  12  and  18  are disconnecting from one another. 
     In some embodiments, after CNs  98  and  99  are connected and locked, electrical modules (not shown) of CAs  101  and  100  are coupled to one another, so that electricity, and various types of signals may be exchanged between cars  12  and  18 . For example, when the electrical modules of CNs  98  and  99  are connected, communication devices  57  of cars  12  and  18 , may exchange at least some signals using a wired communication channel, in addition to or instead of using wireless signals  53  described above. In such embodiments, communication devices  57  are configured to receive a signal indicating the availability of the wired communication channel, and based on the signal, to select between the wired and wireless channels for transmitting the signals. 
     At a dynamic coupling step  110 , while both are still moving, cars  12  and  18  are coupled to one another so that passengers can move from car  18  toward their destination car of vehicle  11 , e.g., car  12 . Step  110  terminates the process for connecting two moving cars  12  and  18 , and after concluding step  110 , car  18  is integrated with vehicle  11  as described in  FIG. 1  above. 
     In some embodiments, a reversed order of the process described in  FIG. 2  may be used, mutatis mutandis, for disconnecting between two cars of vehicle  11 . Note that when de-coupling between cars  12  and  18 , it is essential to reduce the force (e.g., mutual pressure) applied between CAs  100  and  101 , so as to disconnect between CNs  99  and  98 , whereas when connecting between CAs  100  and  101 , it is important to have mutual pressure applied between CAs  100  and  101 , so as to carry out the latching and/or locking described above. Thus, after the extension is enlarged, the rare car (e.g., car  12 ) may slightly accelerate (or the front car may slightly decelerate) to reduce the mutual pressure and to enable the decoupling between CNs  98  and  99 . In some embodiments, when cars  12  and  18  are disconnecting from one another, TEs  87  and  88  may be extended while CNs  98  and  99  are still connected with one another, e.g., as shown for example in step  108 . Subsequently, when distance  112  is sufficiently large, e.g., as shown in step  106 , CNs  98  and  99  are disconnecting from one another and TEs  87  and  88  are collapsing toward cars  18  and  12 , respectively. 
     Note that the damping embodiments described in step  106  above, are also applicable for steps  108  and  110 , as well as for the corresponding steps of the process for disconnecting between any cars (e.g., cars  12  and  18 ) of vehicle  11  Additional embodiments related to the extension and damping are described below. 
     In other embodiments, TEs  87  and  88  may remain collapsed when cars  12  and  18  are disconnecting from one another. In such embodiments, CNs  98  and  99  are disconnecting from one another at about the same time (or shortly before) cars  18  and  12  are decoupling from one another. 
     In alternative embodiments, instead of TEs  87  and  88 , at least one of cars  12  and  18  may have a non-extending element having connectors, such as but not limited to CNs  98  and  99 . These non-extending elements may be used for connecting between cars  12  and  18 , and may also serve as dampers for damping any impact occurring by the coupling between cars  12  and  18 . Coupling cars using such non-extending elements typically require fast communication and good coordination for performing a virtual coupling between cars  12  and  18 . The term “virtual coupling” is described in detail below. Additionally or alternatively, extenders, such as but not limited to TEs  87  and  88 , or any other type of non-telescopic extenders described below, may be used for damping the impact occurred when coupling between cars  12  and  18 . 
     In yet other embodiments, at least one of TEs  87  and  88  may not collapse at step  108 , for example, when connecting between cars  12  and  18  without transferring people and/or other objects between the cars. In the example of  FIG. 2 , cars  12  and  18  may be coupled via TEs  87  and  88  and connected between CNs  98  and  99 , but the bodies of cars  12  and  18  remain separated from one another at a predefined distance (e.g., distance  116  or  118 ). 
     Typically, the processor  55  comprises a general-purpose processor, which is programmed in software to carry out the functions described herein. The software may be downloaded to the computer in electronic form, over a network, for example, or it may, alternatively or additionally, be provided and/or stored on non-transitory tangible media, such as magnetic, optical, or electronic memory. 
     In other embodiments, at least one of cars  12  and  18  may have, instead of or in addition to TEs  88  and  87 , one or more extenders that are not telescopic. For example, an extender shaped as a squeezebox of an accordion may be compressed instead of the collapsing of the TE, and expanded, instead of the extending of the TE. Other examples of a non-telescopic extenders may be designed as a folding fence used in gardens and gates or any other suitable type of a controllable extending and collapsing apparatus. 
       FIGS. 3A, 3B and 3C  are schematic, sectional views of three respective positions of CNs  98  and  99  used for dynamically connecting moving cars  12  and  18  of system  10 , in accordance with an embodiment of the present invention. As described in  FIG. 2  above CNs  98  and  99  are coupled, respectively, to TEs  87  and  88 . 
     Reference is now made to  FIG. 3A . As described in  FIG. 2  above, CNs  98  and  99  are both moving in direction  44 , however, due to the different speeds of cars  18  and  12 . CNs  98  and  99  are actually moving toward one another in opposite directions  70  and  60 , respectively. 
     In some embodiments, CN  99  comprises a housing  61  having a distal end shaped as a cone  64 . CN  99  comprises a disc  66 , which is configured to rotate about a hinge  65 . In the present example, disc  66  is rotated clockwise for connecting between CNs  98  and  99  as will be described in detail in  FIGS. 3B and 3C  below. 
     In some embodiments, a section of the circumference of disc  66  is shaped as an arc  67 , and a notch  63  is formed in arc  67 . A spring  68  is coupled between disc  66  and housing  61 , and a shaft  69  is coupled to a hinge  62 . 
     In some embodiments. CN  98  comprises a housing  71  having a distal end shaped as a cone  74 . CN  98  comprises a disc  76 , which is configured to rotate about a hinge  75 . In a like manner to disc  66  described above, disc  76  is rotated clockwise for connecting between CNs  98  and  99 . 
     In some embodiments, a section of the circumference of disc  76  is shaped as an arc  80 , and a notch  73  is formed in arc  80 . A spring  78  is coupled between disc  76  and housing  71 , and a shaft  79  is coupled to a hinge  72 . Shafts  69  and  79  are typically made from a rigid metal or any other suitable material. Note that shafts  69  and  79  pass, respectively, through openings of cones  64  and  74  of respective housings  61  and  71 , such that the distal end of shaft  69  makes contact with arc  80  of disc  76 , and the distal end of shaft  79  makes contact with arc  67  of disc  66 . 
     Reference is now made to  FIG. 3B . In some embodiments, cones  64  and  74  are shaped such that when CNs  98  and  99  are moving toward one another (e.g., in directions  70  and  60 , respectively), cone  64  fits over cone  74 . When TE  88  moves CN  99  in direction  60 , disc  66  rotates clockwise and brings notch  63  in close proximity to the distal end (i.e., the end not connected to hinge  72 ) of shaft  79 . Moreover, when disc  66  rotates clockwise, spring  68  of CN  99  is being stretched. Similarly, when TE  87  moves CN  98  in direction  70 , disc  76  rotates clockwise and brings notch  73  in close proximity to the distal end of shaft  79 , and spring  78  is being stretched. When discs  66  and  76  are sufficiently-rotated clockwise, the distal ends of shafts  69  and  79  are inserted into notches  73  and  63 , respectively. In some embodiments, the distal ends of shafts  69  and  79  may have a pin, or any other suitable apparatus, for insertion into notches  73  and  63 , respectively. 
     Reference is now made to  FIG. 3C , showing a mechanism for locking CNs  98  and  99  to one another. As described above, the distal ends of shafts  69  and  79  are inserted into notches  63  and  73 , respectively, and are stopping against respective discs  76  and  66 . Subsequently, shafts  69  and  79  are pressed back into CNs  99  and  98 , respectively, causing discs  76  and  66  to rotate until notches  73  and  63  align with shafts  69  and  79 . After shafts  69  and  79  have entered, spring  68  applies to disc  66  force in a direction  82  and spring  78  applies to disc  76  force in a direction  84 , so that notches  73  and  63  spring back into a position where shafts  69  and  79  are extended, and thereby lock CNs  98  and  99  to one another. In the locked position, forces on shafts  69  and  79  and discs  66  and  76  are balanced out, so that CNs  98  and  99  are remained locked. 
     The structure and functionality of CNs  98  and  99  is based on Scharfenberg couplers, provided, for example, by Voith Turbo Scharfenberg GmbH (Salzgitter, Germany). In other embodiments, CAs  100  and  101  may have any other suitable type of couplers or connectors, instead of or in addition to CNs  98  and  99 . 
     In some embodiments, uncoupling between CNs  98  and  99  is executed by rotating at least one of the discs against the force of the respective spring. For example, rotating disc  66  clockwise against the force of spring  68 . In response the clockwise rotation, the distal end of the respective shaft (e.g, shaft  79 ) is released from the respective notch (e.g., notch  63 ), and the same applies for shaft  69  and notch  73 . As a result, CNs  98  and  99  are uncoupled. Note that the coupling and uncoupling of CNs  98  and  99 , as described above, may be carried out manually, or using electrical and/or pneumatic mechanisms controlled, for example, by processor  55  and/or by an operator of the respective cars and/or of system  10 . Additional embodiment and variations are described in detail, after  FIG. 4  below. 
     The embodiments described in  FIGS. 3A-3C  are not limited to trains. In some embodiments, system  10  and the cars thereof (e.g., cars  12  and  18 ), may comprise any other type of transportation vehicle, such as but not limited to a bus, an intercity train, a light train, a suburban rail, an underground train, a boat, an automobile, a truck and an aircraft. Moreover, the cars (e.g., cars  12  and  18 ) of system  10  may transport any suitable types of objects, such as but not limited to, passengers, parcels, cargo and/or freight, or any suitable combination thereof. 
       FIG. 4  is a flow chart that schematically illustrates a method for dynamically connecting two or more moving cars of system  10 , in accordance with an embodiment of the present invention. The method begins at a first distance setting step  200 , with setting a first distance between first and second moving cars. For example, setting distance  116  separating between moving cars  12  and  18  shown in  FIG. 2  above. At an extending step  202 , while cars  12  and  18  are moving, TE  88  of car  12  is extended toward car  18 , and TE  87  of car  18  is extended toward car  12 . 
     At a connecting step  204 , CN  99 , which is coupled to TE  88 , is connected with a mating connector, e.g., CN  98 , of car  18 , as shown for example in step  106  of  FIG. 2  above. At a second distance setting step  206 , a second distance (e.g., distance  118  of  FIG. 2  above), which is smaller than distance  116 , is set for separating between moving cars  12  and  18 , and at the same time, TEs  88  and  87  collapse toward cars  12  and  18 , respectively, so that a combination of controlling the speed of cars  12  and  18  to obtain distance  118  and moving at least one of TEs  88  and  87  enables the latching and/or locking described in  FIG. 2  above. At a car coupling step  208  that concludes the coupling method, cars  12  and  18  are coupled to one another while moving and collapsing TEs  88  and  87  toward cars  12  and  18 , respectively. After concluding step  208 , car  18  is integrated with vehicle  11  as described in  FIGS. 1 and 2  above. 
     Additional Embodiments and Variations 
     Dynamic coupling assumes that the speed of two consecutive components (e.g., cars  12  and  18 ) is known with a relatively high accuracy and known delay. Thus, conventional safety margins (which assume static obstacles) are relatively conservative and therefore, expensive in terms of volume transportation. As such, relative speed (rather than absolute speed) is considered as a key parameter for deriving the safety requirements of system  10 . Measuring relative speed allows two consecutive components (e.g., cars  12  and  18 ) to get in close proximity to one another while maintaining a sufficiently-safe distance therebetween. As described in  FIG. 2  above, by having LCUs  54 , cars are virtually mutually connected and informed of various parameters of one another, such as motion parameters (e.g., speed and acceleration). 
     In some embodiments, the coupling mechanism of system  10  may comprise: CNs  98  and  99  or any other suitable type of automatic coupler, TEs  87  and  88  for extension and damping as described in  FIG. 2  above, a communication channel (e.g., between communication devices  57  of cars  12  and  18 ), sensors  56  for sensing the aforementioned motion parameters and distance between adjacent cars  12  and  18 , processors  55  for controlling the motion parameters, distance between adjacent cars  12  and  18 , and the operation of CAs  100  and  101  for coupling and decoupling between adjacent cars. The coupling mechanism may comprise a hazard and safety control mechanism, for example, using software features for controlling the aforementioned coupling and decoupling in response to input signals, such as detection of obstacles, or receiving negative clearance from the railway signaling system or train control system or other types of hazards along route  33 . 
     In some embodiments described in  FIG. 2  above, the communication channel is capable of transferring distance and speed measurements in real-time, as well as potential hazard alerts, while controlling speed and acceleration of both cars. When the cars are approaching one another, the speed and acceleration are adapted, so as to reduce relative speed, and thereby, allowing safe coupling. When the cars (e.g., cars  12  and  18 ) are sufficiently close to one another (e.g., at step  106  of  FIG. 2  above), processor  55  activates CAs  100  and  101 , so as to lock the automatic couplers (e.g., CNs  98  and  99 ) to one another and latch or be locked using any suitable technique. 
     In some embodiments, the dynamic coupling (as well as decoupling) between adjacent cars  12  and  18  is carried out under the supervision of the aforementioned hazard and safety control mechanism, which is implemented, for example, using processors  55 , and is described in detail below. 
     In some embodiments, LCUs  54  are configured to continuously sense various parameters (as described in  FIGS. 1 and 2  above) and to response to any variation in the dynamics of cars  12  and  18 , so the leading car (e.g., car  18 ) does not change speed before ascertaining that the trailer car (e.g., car  12 ) started braking or reducing speed at a slowing rate determined, for example, by processor  55 . 
     As described in  FIGS. 1 and 2  above, the coupling between cars  12  and  18  is carried out after the front car (e.g., car  18 ) has accelerated and reached the speed of the rear car e.g., car  12 ), so that the rear car can approach the front car from behind and the two cars reach the distance required for coupling (e.g., distance  116  of  FIG. 2  above). TEs  87  and  88  that serve as a coupling extension and damper mechanism, allow cars  12  and  18  that are maintained, e.g., by processors  55 , in controlled distance and speed relative to one another, to couple and latch (e.g., having CNs  98  and  99  locked). Subsequently, TEs  87  and  88  are collapsed toward cars  18  and  12 , respectively, and cars  12  and  18  are now coupled and moving in tandem as cars of vehicle  11 . 
     In some embodiments, there are three types of couplers (i.e., connecting mechanism) for connecting between cars  12  and  18 : (a) a manual coupler, using a mechanical, or pneumatic, or electrical connections, (b) a semi-automatic coupler, having an automatic mechanical connection, but manual only pneumatic and/or electric connections, and (c) fully automated couplers. In some embodiments, the semi-automatic coupler, also referred to herein as a semi- permanent coupler, is designed to ensure a permanent mechanical and pneumatic connection between the different cars of vehicle  11 . The semi-permanent coupler does not have to be uncoupled unless there is a case of emergency or during maintenance of one or more of the connected cars. Both the coupling and the uncoupling of the semi-permanent couplers are carried out manually and must be carried out with both cars. In some embodiments, the semi- permanent coupler has a vulcanized metal-rubber articulation that allows relative movement between the cars. This coupler allows the coupled cars to resist both horizontal and vertical vibrations, as well as rotational movements. One or both of the two couplers between cars is provided with an energy absorption device, which is configured to absorb mechanical forces applied between the cars (e.g., between cars  12  and  18 ). 
     In some embodiments, an automatic coupler is configured to carry out mechanical coupling between two cars, by means of a simple approximation at a recommended speed of about 5 kilometer per hour (KPH), without any manual assistance. The electric and pneumatic connection of the respective cars are carried out automatically at the same time with the mechanical coupling. The automatic coupler allows the coupled cars to resist both horizontal and vertical vibrations, as well as a rotational movement. Uncoupling the cars is also automatic, and is carried out from the driver&#39;s desk, although in case of emergency it can be carried out manually by means of an uncoupling handle. In an embodiment, the automatic coupler is provided with an energy absorption device, configured to collapse under strong impacts for protecting the frames of the involved cars. Such automatic couplers may be supplied by various manufacturers, such as the aforementioned Voith GmbH, and other producers described in U.S. Provisional Patent Application 62/877,853 (attorney docket number 1373-2003) filed Jul. 24, 2019, whose disclosure is incorporated herein by reference. 
     Train virtual coupling is a technology that applies direct (or indirect) communication between adjacent cars, such as cars  12  and  18 , for shortening a safety distance therebetween. In virtual coupling, the specified safety distance takes in account the dynamics (e.g., motion parameters of each car and distance measured between the cars), relying on the communication channel (described above) between cars  12  and  18 , and in the example of  FIG. 2 , automating the response of car  12  (also referred to herein as the trailing car in the present example) to hazard alert provided by car  18  (also referred to herein as the leading car in the present example), so as to prevent collision between cars  12  and  18 . 
     One of the greatest challenges for virtual coupling safety is derailment of adjacent opposite direction rolling stock. In the context of the present disclosure, the term “derailment” refers to a car of system  10  falling out of route  33  undesirably (e.g., by accident). For example, when a train is getting off-track or when an automobile is falling off-road. Such undesired accidents are hazardous for passengers and other objects transported by the cars and vehicles of system  10  or any other transportation system. In these cases, the leading train, about to collide with the derailed train, cannot provide hazard alert in time to the virtually coupled second train, thus the latter does not have time to decelerate and will cause even higher speed collision. The virtual coupling safety is also problematic when approaching diverging junctions as the first train may derail due to junction malfunction and the second cannot brake in time to prevent collision. In some embodiments, system  10  is configured to address safety issues of virtual coupling by shortening the virtual coupling time-window required for physical connection during which it can be assured no opposite train or intersection is present, removing the virtual coupling drawbacks completely. 
     In some embodiments, one or more cars (typically all cars) of system  10  comprise an automatic coupler, such as CAs  101  and  100  having respective CNs  98  and  99  as shown in  FIG. 2  above. The CAs are typically coupled at both side of the car so as to enable connecting with cars at the front and back sides of the car. In the example described in  FIG. 2  above, when car  12  moves in direction  44 , CA  100  is coupled at the front side (e.g., location  90 ) and an additional CA is coupled at the back side (e.g., location  92 ) of car  12 . 
     The embodiments provided herein describe CAs  100  and  101  and the TEs and CNs thereof, but are applicable for all CAs, TEs and CNs of all cars of system  10 . 
     In some embodiments, CNs  98  and  99  are configured to latch and lock automatically in response to having a predefined range of relative speeds between one another (e.g., between about 3 KPH and 5 KPH), using the connecting and locking mechanism described in  FIGS. 3A-3C  above, or by using any other suitable mechanism. Note that CNs  98  and  99  are configured to operate under longitudinal and lateral forces and vibrations, and to support a predefined range of tilting and rotation angles such as requirements specified in various railway engineering standards, e.g., I.S. EN 12663-1:2010, SS-EN 16019:2014, between cars  12  and  18 , for example based on the interaction between cones  64  and  74  described in  FIGS. 3A-3C  above. 
     In some embodiments, each CA of system  10  comprises an electronic module (not shown), such that after CNs  98  and  99  are mechanically connected and locked, the electronic modules of CAs  100  and  101 , are electrically connected, and are configured to produce signals indicative of the coupling status between CNs  98  and  99 . Moreover, when the electronic modules of CAs  100  and  101  are electrically connected, communication devices  57  of CAs  100  and  101 , are configured to exchange at least one of the communication signals over a wired connection (not shown) coupled between the electronic modules of CAs  100  and  101 . Although CAs  100  and  101  are operated using electrical power provided by cars  12  and  18 , respectively, CNs  98  and  99  may be operated (e.g, latching/locking and releasing) manually, for example, in case of emergency. 
     In some embodiments, TEs  87  and  88  (that serve as extenders and dampers as described above) are configured to provide to suppress and/or contain vibration differences between cars  12  and  18  and to sustain longitudinal forces and different required angles of the coupling after connecting CAs  100  and  101  successfully. 
     In some embodiments, CAs  100  and  101  are designed for high speed trains (e.g., trains, metro, and trams) and for automobiles (e.g., buses and minibuses). In such embodiments, each of TEs  87  and  88  is configured to extend to various sizes, such as but not limited to about 3-4 meters for rail cars, and about 0.5 meter for connected automobile cars, or any other suitable extension size, as described for example in  FIG. 2  above. As shown in steps  108  and  110  of  FIG. 2  above, after CNs  98  and  99  are connected, TEs  87  and  88  are configured to collapse toward cars  18  and  12 , respectively. 
     In some embodiments, TEs  87  and  88  are configured for de-touching with a high-speed mechanism in case of hazard before the latching of CNs  98  and  99  and the collapsing of TEs  87  and  88 . In some embodiments, the CNs and TEs of CAs  100  and  101  are designed to comply with collision-related and other forces applied between coupling and decoupling cars, as specified in the respective standards, such as EN  15227  standard, for coupling between cars of trains, automobiles and other types of vehicle described above. 
     In some embodiments, system  10  comprises a direct communication channel between cars  12  and  18 , and between any two or more connecting cars. In the example of  FIG. 2  above, the communication channel is set between communication devices  57  that exchange communication signals, such as wireless signals  53 , for maintaining various operations, such as but not limited to relative speed, absolute speed, communication delay, acceleration and location between cars  12  and  18 . 
     In some embodiments, the communication channel is configured to support bidirectional traffic, to maintain the direct link within a distance between about 20 km and fully connected between cars  12  and  18  (may have different specification for different types of vehicles, for example, train cars and automobile cars), and a communication delay smaller than about 1 millisecond (ms) when the distance between cars is smaller than about 1 km. 
     In some embodiments, the direct communication, also referred to herein as “point to point” communication, is encrypted and authenticated for improved safety and reliability. Moreover, the direct communication provides LOS (loss of signal) or loss of communication indication, when the communication is lost, with a delay of less than 1 ms. 
     In some embodiments, the cars of system  10  may have an external shape for obtaining an aerodynamic shape when connected with one another. For example, after coupling between adjacent cars, the backside of the leading car may fit over the front side of the training car, such that the connected cars appear as a single car. One example of this embodiment is shown in  FIG. 2  of the aforementioned U.S. Provisional Patent Application 62/877,853. 
     In some embodiments, sensors  56  for measuring the distance and speed, are configured to measure the distance between cars  12  and  18  constantly (e.g., a range between every about 100 milliseconds and about 1 second) and accurately. The measurements are sufficiently- accurate to enable bringing cars  12  and  18  safely to a distance smaller than about one meter. For example, at an inter-car distance between about 15 km and about 1 m sensors  56  are configured to measure, and processor  55  is configured to control a distance value smaller than about ±3% of the actual distance. Similarly, for any speed between 450 KPH and 50 KPH sensors  56  are configured to measure, and processor  55  is configured to control a speed value smaller than about ±3% of the actual speed of each of the cars to be coupled or decoupled, and the relative speed between the respective cars (e.g., cars  12  and  18 ). 
     In some embodiments, system  10  and each LCU  54 , have a fail-safe mechanism and are configured to produce an alert in response to any sort of failure to obtain the specified motion parameters and distance between cars  12  and  18  (and between any cars of system  10 ). 
     In an embodiment, the automatic speed and acceleration control mechanism helps control the cars relative positions before, during and after coupling and/or decoupling. Using the distance and speed measurements, at least one processor  55  (e.g., the master processor or both processors  55 ) is configured to generate coupling control commands to cars  12  and  18  to adjust their respective speed and acceleration for a fully automatic feedback until concluding the coupling and/or decoupling process, and as long as cars  12  and  18  are within the aforementioned distances (e.g., up to 15 km) between one another. 
     For example, (a) each car (e.g., cars  12  and  18 ) receives its own acceleration or deceleration control feedback, (b) in responds to the feedback, a command to adjust one or more motion parameters is generated within up-to 1 second, and/or speed of about 90 meter per second, and/or acceleration between about 0.5 and 3 meter/second 2 . 
     In some embodiments, the automatic speed and acceleration control mechanism of LCU  54  is configured to respond to stop hazard alert with an emergency procedure for stopping the train. In the emergency procedure, the leading car (e.g., car  18 ) sends, directly or indirectly to the rear car (e.g., car  12 ), a signal indicative of a hazard (also referred to herein as a hazard signal), and car  18  does not start decelerating before receiving from car  12  acknowledgment to the hazard signal and an indication that car  12  has started to decelerate. The emergency procedure ensures that the leading car will start decelerating only after the rear car has already started to decelerate, and therefore, the rear car will not collide into the leading car. Moreover, in response to a communication error, the automatic speed and acceleration control mechanism of LCU  54  is configured to perform the emergency procedure, such that, in response to a hazard alert, car  12  decelerates before car  18  starts decelerating. The automatic speed and acceleration control mechanism of LCU  54  is configured to maintain a full duplex channel between processors  55  of cars  12  and  18 , and having a continuous communication mechanisms to ensure that the communication between communication devices  57  is up and running at least when cars  12  and  18  are within a distance smaller than about 15 km from one another. 
     In some embodiments, the hazard and control mechanism, e.g., between cars  12  and  18 , is designed such that cars  12  and  18  are considered as a single vehicle comprising them, while the coupling control is autonomous to allow low latency and fast response. Typically, the front car (e.g., car  18 ) continues to accelerate when a hazard occurs, so as to avoid the rear car (e.g., car  12 ) from colliding with the front car (e.g., car  18 ). Note that this feature does not change in essence the safety margins (also referred to herein as the safe distance or safety distance), the rear car&#39;s safety margin is the margin that should be taken into account, at least when the front car has not yet reached the speed of the rear car. Moreover, when the front car, e.g., car  18 , is in the range of the safety margin from a forward potential obstacle, car  18  can still accelerate and maintain the aforementioned safety distance from car  12 .  FIG. 3  of the aforementioned U.S. Provisional Patent Application 62/877,853, shows an example graph of the acceleration of a front car (e.g., car  18  in the example of  FIG. 2 ) in a train coupling case (represented in  FIG. 2  by car  12 ) and the fact the safety margin is not compromised by continuing the acceleration after the hazard alert was issued. In some embodiments and as shown in the aforementioned graph, the total braking distance of the rear train (refers to car  12  of the present disclosure) is not compromised, the front car (refers to car  18  of the present disclosure) continues to accelerate and gain speed for about eight more seconds in order to avoid the rear train from reaching the front car. In the example of the aforementioned graph, both cars reach the same speed and continue with the same deceleration rate until obtaining full stop. A safety margin between the trains (e.g., cars  12  and  18  in the present disclosure) that compensates for the variance in deceleration rates and other mismatches can be maintained by maintaining the acceleration of the front car (e.g., car  18 ), or by delaying the deceleration of the rear car, which requires extended safety margin of the rear train towards a potential obstacle and/or other hazards, by the safety margin. 
     In some embodiments, any hazards detected by any entity of system  10  is communicated (e.g., by car  18 ) to car  12  by using the aforementioned point to point communication channel. Additionally or alternatively, any hazards detected by any entity of system  10 , may be communicated to at least one of cars  12  and  18 , via the aforementioned controlled sub-system (e.g., the CCU) or any other suitable third party. For example, a hazard detected by car  18  may be transmitted to the CCU, and from the CCU to car  12 . Note that indirect communication typically add to the communication-related delays, and therefore, may require specifying larger safety margins as compared to the safety margins specified when cars  18  and  12  are communicating directly. In response to the hazard alert, LCU  54  of car  12  sends signals indicative of acknowledgment for the hazard alert, and an indication that car  12  started decelerating using any suitable braking system thereof. Subsequently, processor  55  of car  18  calculates and verifies that the current relative speed between cars  12  and  18 , is similar (approximately equal) to the relative speed between cars  12  and  18  before receiving the hazard alert. In some embodiments, during the deceleration, processors  55  of cars  12  and  18  are configured to maintain a predefined minimal safety margin between cars  12  and  18 , while the car  12  continues to brake, the control is maintained by car  18 , which may or may not receive a deceleration command. In other words, the safe distance between cars  12  and  18  is maintained by first decelerating car  12  (which is the rear car), and only after obtaining suitable predefined conditions, such as but not limited to, safe distance and relative speed between cars  12  and  18 , car  18  (which is the front car) starts to decelerate. Note that the same embodiments and procedure are applicable also in response to a communication loss between cars  12  and  18 , or in response to any other safety-related event (e.g., a fire in car  12  or in car  18 ). 
     As described in  FIG. 1  above, vehicle  11  and the cars of system  10  may comprise any other suitable type of transportation equipment, such as but not limited to a bus, an intercity train, a light train, a suburban rail, an underground train, a boat, an automobile, a truck, and a cargo and/or freight carrier (e.g., a train, a truck or a ship, or any other type of transportation equipment or vehicle described above). In yet other embodiments, vehicle  11  may comprise an aircraft (e.g., a drone) configured to carry passengers and/or parcels along a predefined route, and the cars may comprise smaller drones configured to load and unload the passengers and/or parcels between the aircraft and the stations. Embodiments described herein are related to automobiles, such as buses and minibuses, but are also applicable, mutatis mutandis, to one or more of the other types of transportation systems described above. 
     Traditional mechanisms for connecting between two buses or minibuses, comprises a swivel mechanism used for connecting two bus cabins into a single unit having two cabins. That solution is unsuitable for dynamic coupling as it is made of fabric and unable to connect and disconnect between two adjacent buses as required. In the embodiments described below, the term “car” refers to any suitable type of car, such as but not limited to a bus and a minibus. 
     In some embodiments, a dynamic coupling mechanism is configured to connect two cars and allow safe passage of passengers between the connected cars. Coupling is carried out at high speeds (e.g., at about the speed limit at the respective section of the route) so as to prevent the rear car from reducing the speed (the coupling may also be carried out at low speeds, e.g., in close proximity to a junction). The coupling of several cars into a single vehicle (such as vehicle  11  of  FIG. 1  above) may create a very large convoy-like vehicle which may cause traffic complications, for example in junctions and in curvy section of the route. 
     In some embodiments, in order to accommodate all road conditions, the vehicle (also referred to herein as a combo-vehicle, is configured to split before junctions and/or curves into multiple sub-vehicles, each of which comprising one or more cars, and to reconnect for generating the combo-vehicle after passing the junction or curve. For example, in fully autonomous intersections, the autonomous combo-vehicles may refrain from blocking the junction by disconnecting between two or more cars, and reconnecting between the respective cars after passing the junction. In the example of  FIG. 1 , in case of a blocked intersection between stations  22  and  24 , vehicle  11 , which comprises (after coupling with car  18 ) cars  18 ,  12 ,  14  and  16 , may disconnect between cars  12  and  14 , so as to split into two pairs of cars before the intersection (e.g., cars  18  and  12 , and cars  14  and  16 ) and reconnect between cars  12  and  14  after passing the intersection. In this example, processor  55  of car  12  may initiate the disconnection in response to receiving from sensors  56  of car  12 , a signal indicating that cars  14  and  16  are blocking the intersection. Similarly, processors  55  of cars  11  and  14  may initiate the reconnection in response to receiving from sensors  56  of car  16  (the rear-most car of vehicle  11 ), a signal indicating that cars  14  and  16  have already passed through the intersection. 
     In some embodiments, the coupling mechanism is also configured to accommodate large angles of vehicle  11  in case of sharp turns (e.g., in a junction), or to split and reconnect before and after a turn, depending on the requirements of the respective route. In other embodiments, when vehicle  11  is used in routes that cross highways and do not have turns (or having non- sharp curves), the cars of vehicle  11  may have, instead of CAs  100  and  101 , simpler coupling assemblies, e.g., for reducing the overall cost of system  10 . 
     In some embodiments, the coupling assembly for coupling between two buses (e.g., cars  12  and  18 ) is configured to: (a) connect and disconnect between cars  12  and  18 , (b) allow passengers to pass between the front bus (e.g., car  18 ) and the rear bus (e.g., car  12 ), (c) suppress and/or contain the forces and vibrations of each car, and between cars  12  and  18 , (d) support turning of vehicle  11  at an angle up to ninety degrees, (e) sustains crash forces and maintain vehicle  11  as a single unit (e.g., a single car), (f) electrically connect between cars  12  and  18  for electricity and connectivity as required, (g) support automatic coupling on differential speeds of up-to 5 KPH between adjacent cars, (h) support manual and automatic connection and disconnection between cars  12  and  18 , (i) have extensions and dampers, such as TEs  87  and  88 , to allow connection of cars  12  and  18  within a suitable distance (e.g., of about two meters), and (j) collapse TEs  87  and  88  after connecting between CNs  98  and  99  and having them locked and/or latched. 
     In some embodiments, the communication channel between buses has the same features of the communication channel described above for exchanging communication signals between cars of any sort of a transportation system. 
     In some embodiments, when applied to automobiles, e.g., when cars  12  and  18  comprise buses, system  10  is configured to carry out the dynamic coupling and/or decoupling between the buses, using a safety distance smaller than a safety distance used when connecting between cars of a train. 
     In some embodiments, before direct communication is established between cars  12  and  18  (of any type of transportation system), the safety distance cannot not be reduced to a dynamic safety distance, and has to remain at the safety distance required according to existing regulations (e.g., of route  33 ), which assumes a conventional approach to the obstacle. 
     Even though the front car (e.g., car  18 ) is located inside the safety margin of the rear car (e.g., car  12 ), system  10  is configured for maintaining safety distance by continuing to accelerate car  18 , and also control the speed thereof, as long as needed. At the same time, the safety margin of car  18  must be greater than required according to the existing regulations of route  33 , in order to account for the needed safety margin between cars  12  and  18 . 
     In some embodiments, safety is maintained by controlling the speed and acceleration of car  18  so as to prevent car  12  from colliding with car  18  due to high differential speed therebetween. The safety is also maintained by transferring information about hazards, e.g., from car  18  to car  12 , and by extending the safety margin requirements between cars  12  and  18 . 
     Although the embodiments described herein mainly address any type of transportation systems, such as trains, the methods and systems described herein can also be used in other types of transportation systems and other applications. For example, the disclosed techniques may be used, mutatis mutandis, for connecting between cars of any type of the aforementioned vehicles that are moving in the same direction and/or to a similar or common destination, with or without transferring passengers or goods between the cars. Moreover, the disclosed techniques may be used to also allow automation on assembling between entities like trains, or any other type of vehicles, in staging yards, automatically and while the cars are in motion. 
     It will thus be appreciated that the embodiments described above are cited by way of example, and that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and sub-combinations of the various features described hereinabove, as well as variations and modifications thereof which would occur to persons skilled in the art upon reading the foregoing description and which are not disclosed in the prior art. Documents incorporated by reference in the present patent application are to be considered an integral part of the application except that to the extent any terms are defined in these incorporated documents in a manner that conflicts with the definitions made explicitly or implicitly in the present specification, only the definitions in the present specification should be considered.