Intercommunication system for vehicle An intercommunication system for a vehicle is disclosed including a judging mechanism for detecting whether a corner exists ahead of a subject vehicle in a traveling direction on a road based on outputs from a navigating mechanism and a map information outputting mechanism in a navigation system. It is judged whether the vehicle speed of the subject vehicle is excessive or an overspeed for safely passing through a detected corner. If the vehicle speed of the subject vehicle is an overspeed, the speed of the vehicle is reduced through an automatic vehicle speed control mechanism and/or an alarm means which alerts the vehicle driver of the overspeed condition. A mechanism is also provided for detecting whether another vehicle is traveling through or approaching a detected corner. If another vehicle is detected, when the subject vehicle reaches a position which is a predetermined distance short of the corner, intercommunication between the subject vehicle and the other vehicle passing through the corner is initiated pertaining to the vehicle speed, the traveling direction and the like through the communication means, so that the subject vehicle can safely and reliably pass by the other vehicle. Vehicle guiding system A vehicle guiding system enables a plurality of vehicles to run in a platoon with minimum assistance from drivers, and is intended to enhance effective use of from auto-drive lane. When the vehicle runs in the platoon, a front running vehicle detects its displacement from a magnetic nail, and calculates a steering amount to be corrected (i.e. control variables). The front running vehicle not only controls its own movements on the basis of the control variable data but also transmits them to a following vehicle. The following vehicle does not detect its displacement from the magnetic nail, but controls its steering amount on the basis of the received control variable data. The first following vehicle transfers the control variable data to a further following vehicle. The further following vehicle simply receives the control variable data from the following vehicle, and does not calculate its own control variables. This reduces a distance between the vehicles which is necessary for each vehicle to perform such calculation. Vehicle speed and safety warning system A vehicle speed and safety system includes a stationary transmitting device positioned on a side of a road for generating and transmitting a signal indicative of a speed limit for a respective portion of the road and a unit positioned within a vehicle. The unit includes a receiver for receiving the signal indicative of a speed limit from the transmitting device. A microprocessor analyzes the received signal to determine a posted speed limit represented by said signal, monitoring a speed of the vehicle and compares the determined speed limit to the monitored speed. A display generates an alarm signal when the microprocessor determines the monitored speed exceeds the speed limit. The signal indicative of a speed limit is preferably transmitted at a frequency unique to the speed limit whereby each frequency represents a 5 mile per hour group of speed limits. Relative positioning for vehicles using GPS enhanced with bluetooth range finding A relative vehicle positioning system for a vehicle includes a GPS antenna adapted to receive satellite signals generated in response to relative vehicle positioning and generate therefrom a GPS signal. A Bluetooth radio is adapted to exchange bearing information with a second vehicle and generate therefrom a PVT signal. A GPS unit including a controller is adapted to receive the GPS signal and the PVT signal, the GPS unit is further adapted to generate therefrom a GPS-Bluetooth relative position signal. Method and apparatus for detecting and responding to an absence of journey-related information In a vehicle equipped with a dedicated short-range two-way communications system to acquire and otherwise participate in a roadway information service, method and apparatus are provided to detect (301) an absence of the availability of such a service and to respond by substituting (302) roadway information from other sources and to provide notice (303) to the driver regarding the absence of realtime service information and/or the present use of substituted roadway information. GPS vehicle collision avoidance warning and control system and method GPS satellite (4) ranging signals (6) received (32) on comm1, and DGPS auxiliary range correction signals and pseudolite carrier phase ambiguity resolution signals (8) from a fixed known earth base station (10) received (34) on comm2, at one of a plurality of vehicles/aircraft/automobiles (2) are computer processed (36) to continuously determine the one's kinematic tracking position on a pathway (14) with centimeter accuracy. That GPS-based position is communicated with selected other status information to each other one of the plurality of vehicles (2), to the one station (10), and/or to one of a plurality of control centers (16), and the one vehicle receives therefrom each of the others' status information and kinematic tracking position. Objects (22) are detected from all directions (300) by multiple supplemental mechanisms, e.g., video (54), radar/lidar (56), laser and optical scanners. Data and information are computer processed and analyzed (50,52,200,452) in neural networks (132, FIGS. 6-8) in the one vehicle to identify, rank, and evaluate collision hazards/objects, an expert operating response to which is determined in a fuzzy logic associative memory (484) which generates control signals which actuate a plurality of control systems of the one vehicle in a coordinated manner to maneuver it laterally and longitudinally to avoid each collision hazard, or, for motor vehicles, when a collision is unavoidable, to minimize injury or damage therefrom. The operator is warned by a heads up display and other modes and may override. An automotive auto-pilot mode is provided. GPS vehicle collision avoidance warning and control system and method GPS satellite (4) ranging signals (6) received (32) on comm1, and DGPS auxiliary range correction signals and pseudolite carrier phase ambiguity resolution signals (8) from a fixed known earth base station (10) received (34) on comm2, at one of a plurality of vehicles/aircraft/automobiles (2) are computer processed (36) to continuously determine the one's kinematic tracking position on a pathway (14) with centimeter accuracy. That GPS-based position is communicated with selected other status information to each other one of the plurality of vehicles (2), to the one station (10), and/or to one of a plurality of control centers (16), and the one vehicle receives therefrom each of the others' status information and kinematic tracking position. Objects (22) are detected from all directions (300) by multiple supplemental mechanisms, e.g., video (54), radar/lidar (56), laser and optical scanners. Data and information are computer processed and analyzed (50,52,200,452) in neural networks (132, FIGS. 6-8) in the one vehicle to identify, rank, and evaluate collision hazards/objects, an expert operating response to which is determined in a fuzzy logic associative memory (484) which generates control signals which actuate a plurality of control systems of the one vehicle in a coordinated manner to maneuver it laterally and longitudinally to avoid each collision hazard, or, for motor vehicles, when a collision is unavoidable, to minimize injury or damage therefrom. The operator is warned by a heads up display and other modes and may override. An automotive auto-pilot mode is provided. Inter-vehicular communication method To provide an inter-vehicular communication method which enables a plurality of vehicles to efficiently exchange information. A plurality of vehicles are assigned identification numbers (IDs) and perform transmission of information in order, on the basis of their identification numbers. A time which is allocated so that each of the vehicles can perform a transmission, is constant (one cycle=4 ms), and a time at which the vehicle of ID=1 starts its first transmission is set as a reference time. The vehicles of ID=2, ID=3 and ID=1 . . . sequentially perform their transmissions 4 ms, 8 ms and 12 ms . . . after the reference time. Thus, it is possible to avoid a problem that the plurality of vehicles perform their transmissions at the same time, and it is also possible to minimize the waste of time and to exchange information in a short time. System and method for speed limit enforcement A system for enforcing highway speed limits comprising an antenna and one or more sensors positioned on a vehicle, the antenna capable of receiving data indicative of a speed limit for a roadway, the one or more sensors capable of gathering data indicative of a driving pattern of the vehicle, and a processing unit in communication with the antenna and the one or more sensors, the processing unit receiving the speed limit data from the antenna and the driving pattern data from the sensors, analyzing the speed limit data and the driving pattern data to asses whether a predetermined action should be initiated and initiating a predetermined action in response to the assessment. Automatic vehicle following control system When vehicles run in a platoon, a status indicative of a malfunction or the like of a following vehicle is transmitted to a leading vehicle, so that the leading vehicle can take an appropriate action. Specifically, an automatic vehicle following control system controls a plurality of unattended following vehicles, each comprising an electric vehicle, to run in tandem in follow mode to an attended leading vehicle. Each of said following vehicles has a remaining capacity detecting unit for detecting a remaining capacity of a battery on the following vehicle, and transmitting information of the detected remaining capacity via vehicle-to-vehicle antennas to the leading vehicle. The remaining capacities of the batteries on the following vehicles are displayed on a display unit of the leading vehicle. When a remaining capacity of a battery on an electric vehicle is lowered, since the maximum output power of a motor on the electric vehicle is reduced, the electric vehicle cannot run in a platoon at a high speed. If the remaining capacity of the battery on the electric vehicle is detected as being lower than a predetermined level, then the speed of the leading vehicle is automatically lowered to enable the following vehicles to run continuously in a platoon at a relatively low speed. Danger warning and emergency response system and method Surveillance platforms in airborne craft (8,10), land based vehicles (12), vessels at sea or fixed structures (14) detect dangers using conventional scanners and transmit information signals describing the dangers to a control center (2) which analyzes the data and determines the degree of danger and its geographic extent. The center generates a danger warning and emergency response including a danger index. The warning/response message identifies the degree of danger (danger index 144) and the GPS coordinates (142) of the impacted geographic area for a wide region or regions of the earth (FIGS. 2-6). A vulnerability index (FIG. 16) determined using neural networks (FIGS. 13-14) and fuzzy logic (FIGS. 15-20) enables a prioritized warning/response. The center broadcasts (18) the danger warning and emergency response (FIG. 9) to a large population of remotely located warning devices (11), such as a network of pagers each of which has a GPS receiver (6,28). The pagers compare the received danger coordinates with their own GPS coordinates and each pager determines the extent to which it is in danger. The warning device automatically issues a warning signal or signals, which may be audible, visual or vibratory, appropriate to the degree of danger. Emergency manned vehicles may also directly receive the broadcast warning/response and be immediately alerted to act appropriately relative to the degree of danger. One embodiment broadcasts (16) directly to home T.V.'s and radios (17) which have internal GPS receivers and which display/annunciate an emergency message customized to that receiver resulting from the internal comparison of the danger coordinates versus the local receiver coordinates. Vehicle platoon control system A target motor vehicle is established for a platoon of motor vehicles running on a road, and motion information of the target motor vehicle is transmitted to the motor vehicles which follow the target motor vehicle through intervehicular communications. Each of the following motor vehicles controls itself to run in platoon based on the transmitted motion information. Castor A castor comprises a fork (10) carrying an axle (11) which extends through an aperture in both limbs (12 and 13) and by which a single wheel comprising two discs (14 and 15) is mounted on the fork (10). A roller bearing (22) is mounted on the axle (11). Each disc, (14, 15) comprises a radially outwardly extending annular disc portion (23, 24) and a tubular portion (25, 26) which projects to one side of the respective disc portion (23, 24). The tubular portions (25 and 26) are snap-fitted together, one within the other, and together form the single wheel which has two rims (27 and 28). The roller bearing (22) is fitted into the bore of the tubular portion (26) whereby the single wheel is supported thereon for rotation. The tubular portion (26) provides a plain bearing support for the tubular portion (25) of the other disc (14). Relative angular movement between the discs (14 and 15) is possible because of that. The interengaged tubular portions (25 and 26) extend through the central aperture of a ring (35) which is supported between the discs (14 and 15) by the fork (10), being connected to a bridgepiece (30) thereof by a snap-fitting engagement. The central aperture of the ring (35) is oval. There is a clearance between it and the tubular portion (25) above and below but not at the sides. A brake pad (39) is fitted to the bottom of the ring (35) to rest on the surface of a moving walkway when the rims (27 and 28) of the discs (14 and 15) of the single wheel are received in the grooves (41) on the surface of the moving walkway.