Abstract:
A method and system for determining right of way for a plurality of mobile units at an intersection. The method and system include collecting position and movement information about the plurality of mobile units approaching the intersection; storing a plurality of rules about right of way at the intersection; accessing information about geometry of the intersection; calculating which one or more of the plurality of the mobile units have right of way to enter the intersection, responsive to the position and movement information, the stored rules and the information about geometry of the intersection; and wirelessly transmitting right of way indication signals to one or more of the plurality of the mobile units.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This patent application is related to U.S. patent application Ser. No. 11/852,054, filed on Sep. 7, 2007 and entitled “SYSTEM AND METHOD FOR SHORT RANGE COMMUNICATION USING ADAPTIVE CHANNEL INTERVALS”; and U.S. patent application Ser. No. 11/859,978, filed on Sep. 24, 2007 and entitled “METHOD AND SYSTEM FOR BROADCAST MESSAGE RATE ADAPTATION IN MOBILE SYSTEMS.” 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to intelligent vehicle systems and more specifically to determining which vehicle(s) have right of way at an intersection and communicating that information to the vehicles. 
       BACKGROUND OF THE INVENTION 
       [0003]    There is increasing efforts for integrating communication and computing technologies into motor vehicles to improve the safety and efficiency of roadways. For example, the US government has an ongoing Intelligent Transportation Systems initiative (US Department of Transportation, Intelligent Transportation Systems). 
         [0004]    The ability to determine the location of moving vehicles via a Global Positioning System (GPS) or other location determination means for the purpose of collision avoidance is known, for example, see, U.S. Pat. No. 6,405,132, which describes an accident avoidance system. Additionally, U.S. Pat. No. 6,281,808 describes an intelligent control of traffic signals. 
         [0005]    However, these systems and methods do not address an automated determination and dissemination of right of way information when multiple vehicles approach an (uncontrolled) intersection. 
       SUMMARY 
       [0006]    In some embodiment, the present invention is a method and system for determining right of way for a plurality of mobile units at an intersection. The method and system include collecting position and movement information about the plurality of mobile units approaching the intersection; storing a plurality of rules about right of way at the intersection; accessing information about geometric and/or map representation of the intersection; calculating which one or more of the plurality of the mobile units have right of way to enter the intersection, responsive to the position and movement information, the stored rules and the geometric and/or map representation information; and wirelessly transmitting right of way indication signals to one or more of the plurality of the mobile units. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  shows an exemplary configuration of a stationary (roadside) unit, according to some embodiments of the present invention. 
           [0008]      FIG. 2  illustrates a system for determining right of way at a traffic intersection, according to some embodiments of the present invention. 
           [0009]      FIG. 3  illustrates an exemplary processing flow associated with determining the right of way, according to some embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    In some embodiment, the present invention includes a stationary communications and processing unit located near a traffic intersection, the intersection being either uncontrolled or having a traffic signal that is not operational. The stationary unit has access to a map and/or geometric representation (for example, in a geographical information system (GIS) format) of the intersection, and to right of way and safety rules related to the intersection. The stationary unit collects real-time position and movement information about one or more vehicles approaching the intersection as well as the status of the traffic signal, if one exists. Using this information, and taking into account safety rules and the map response information, the stationary unit determines which vehicle(s) have right of way at the intersection and then communicates that information to the vehicles. 
         [0011]      FIG. 1  shows an exemplary configuration of a roadside unit, according to some embodiments of the present invention. A stationary unit, for example, roadside unit  10  may be positioned near an intersection and may include wireless communications means, such as a transceiver  12 , allowing connectivity with the vehicles approaching an intersection. A processing unit  11  calculates and generates right of way indications information  14 . Although shown local to the roadside unit, the processing unit may be remote to the roadside unit. The roadside unit  10  also includes knowledge of the intersection and surrounding geometry, for example, via stored detailed map information  16  stored in a database (storage medium). This information knowledge of intersection may be stored remotely and communicated to the roadside unit on demand basis. 
         [0012]      FIG. 2  illustrates a system (environment) for determining right of way at a traffic intersection, according to some embodiments of the present invention. Vehicles  21  include wireless communications capability, allowing connectivity with one or more roadside units. Vehicles  21  may also include operator interface, with the ability to indicate right of way (or lack thereof), for example in a way of display, voice activated indication, and/or sensors, servos and actuators for automatically controlling the movements of the vehicles, for example, in the case of un-manned vehicles. Vehicles  21  may also include position determination capability, where accurate and timely mobile information  13  is determined and communicated to the roadside unit, allowing the roadside unit to track and predict vehicle trajectories. The positioning capability used to determine the positions of the vehicles  21 , may be onboard the vehicles, for example, satellite based, like GPS, differential GPS, a combination of GPS and future satellite systems, or may be using embedded sensors  23  in the roadside unit, and/or around the intersection, or may use combinations of such positioning methods to yield accurate, lane and sub-lane level positioning. Existing navigation units in the vehicle may be used for some of these functions. 
         [0013]    Additionally, the system may include an out of band (e.g., wireline) communications means  24 , that allows the roadside unit  10  to receive such information as operational status from a local traffic signal  22 , traffic status from the local sensors  23 , database and configuration updates  17  from a remote source, and the knowledge of the intersection if such information is stored remote to the roadside unit. 
         [0014]    Using the knowledge of the intersection and surrounding locale, the processor unit  11  evaluates vehicle (mobile unit) movement in the context of the intersection and local environment. Vehicle movement information includes at least vehicle location. From a series of location updates, vehicle direction, speed, and acceleration may be either calculated onboard the vehicle and reported to the roadside unit, or calculated in the processor associated with the roadside unit. Additional information that pertains to vehicle movement may be included. This additional information may include real-time information such as vehicle braking or turning status. The additional information may also include vehicle parameters that affect the vehicle&#39;s movement or priority, such as weight and size, or vehicle status (for example, emergency vehicle). Local information may include the route of roads entering the intersection, prevailing speed limits on those routes, location of turn-only lanes, size and orientation of the intersection itself, etc. In some embodiments, the local information (or a portion thereof) is received from a central source. The local information may be entered in the roadside unit directly or via messages received over a network connection. The evaluation in the processor includes such calculations as a prediction on when the vehicle will reach the intersection, the path it will take, and when it will exit the intersection. 
         [0015]    Real time information may include the location/heading/speed of approaching traffic, vehicle acceleration, and vehicle capabilities, such as the ability to accept and process right of way messages. This vehicular information may be received via reports or messages from the vehicles themselves, as well as from sensors (for example, cameras, radar, magnetic strips embedded in the roadway, etc.) positioned in proximity of the intersection. Real time information may also include prevailing conditions that affect traffic, such as weather, road condition and visibility, lane closures, constructions, etc.). This information may be received by the stationary unit from a central source, and/or from a local source (e.g., a road work crew, and/or various local sensors). In some embodiments, the prevailing conditions that affect traffic and the road are given different importance weights. For example, if a road is closed, no matter what, no vehicle would be allowed to go through, if the road is wet, the importance of the speed of the vehicles is increased, or if the visibility is weak, the importance of distance to the intersection is increased. 
         [0016]    The wireless communication means (for example,  12  in  FIG. 1 ) may be any communications that allows low-latency information transfer between vehicles and the stationary unit. One technology particularly suited to this purpose is alternately known as wireless access in vehicular environments (WAVE) or dedicated short range communications (DSRC). Vehicles could automatically generate periodic updates of their positions and status and/or the roadside unit can poll the vehicles for this information. 
         [0017]    Traffic rules are construed and programmed based on the prevailing laws in effect at the locale, applied to the specific topology of the intersection. Some simplified examples of such rules are shown here in the form of right of way priority lists for two exemplary scenarios. A vehicle whose trajectory will not cause a collision or near-collision with any other vehicle is granted right of way. Otherwise, the vehicle(s) meeting the criterion highest on the list is granted right of way over all other approaching vehicles.
   1—Minor road crossing a major road:
       i) Emergency vehicle   ii) Through traffic on major road.   iii) Right turning vehicle from major road.   iv) Left turning vehicle from major road.   v) Through traffic on minor road.   vi) Right turning vehicle from minor road.   vii) Left turning vehicle from minor road.   
       2—Crossing of two minor roads:
       i) Emergency vehicle   ii) First vehicle to the intersection.   iii) In the case of simultaneous arrivals:
           (1) If vehicles arrive at adjacent intersection entrances, the rightmost vehicle.   (2) If vehicle arrive from opposite intersection entrances, the through or right-turning vehicle(s).   
           
       
 
         [0032]    The vehicles that receive the right of way messages from the stationary unit may act on the information in different ways depending on system design and vehicle capabilities. An on-board light or display (e.g., red/yellow/green) may be used to indicate right of way to the driver. Alternately, or in conjunction, different audible tones could express that information. Language-based information could also be provided, audibly, and/or visually. If the vehicle is equipped with an automatic control feature, the right of way information could be used by the vehicle controller to invoke braking, steering, and/or accelerating/decelerating controls to prevent the vehicle from entering the intersection or parts thereof if right of way has not been granted. 
         [0033]      FIG. 3  illustrates an exemplary process flow associated with determining the right of way, according to some embodiments of the present invention. In block  31 , the process collects infrastructure status information, such as whether the local traffic signal is functional. From this information, in block  32 , the process determines whether a right of way determination process is needed at the current time, for example, if the signal is not functional. If a determination process is needed, the process collects mobile unit status, in block  33 , for example from wireless signals and/or roadside sensors. If no mobile units (vehicles) are detected (block  34 ), the process continues monitoring for the presence of any newly-arrived vehicles. If mobile units are detected, the process invokes the right of way rules to determine which mobile unit or units has right of way, in block  35 . The process then reports the result to all present mobile units, in block  36 . Upon receiving the right of way determination results, the vehicles act according to the results, as explained above. 
         [0034]    An exemplary scenario follows. Assume that multiple intelligent vehicles approach an intersection and the traffic signal at the intersection is temporarily disabled due to a failure. The vehicles at intervals automatically report their positions, directions, and speeds to a stationary unit located at or near the intersection. Using its knowledge of the intersection geometry, programmed traffic rules, vehicles&#39; trajectories, and local information (such as weather or road condition) the roadside unit sends right of way messages or commands to each of the vehicles, which are in turn conveyed to the drivers or to the control systems of each vehicle. For example, north-south bound vehicles are sent a STOP message, conveyed to drivers by a red dashboard light and/or an audible command. East-west bound vehicles are sent a PROCEED WITH CAUTION message, displayed perhaps as a green/yellow light and/or audible indication. Once the initial east-west bound vehicles clear the intersection, subsequent east-west bound vehicles receive STOP messages, and north-south bound vehicles receive PROCEED WITH CAUTION messages. 
         [0035]    Different countries or legal jurisdictions may have different rules for right of way. Different rules may include granting priority to the first vehicle to arrive, the vehicle on the more major roadway, or the vehicle arriving from the other vehicle&#39;s right. Thus the right of way determination algorithm is programmed to reflect local laws. 
         [0036]    In some embodiments, the roadside unit recognizes (e.g., via the above-mentioned sensors) an approaching vehicle that does not have the ability to process the right of way messages, that is, a non-intelligent vehicle. In this case, the roadside unit&#39;s right of way determination may hold back the intelligent vehicles to allow the non-intelligent vehicle to pass safely. In some embodiments, the roadside unit recognizes emergency vehicles and grants them right of way over non-emergency vehicles. 
         [0037]    In some embodiments, the roadside unit considers turning intentions of a vehicle determined through any of a number of means, such as location of the vehicle in a turn lane, direction vector of the vehicle or activation of a turn signal within the vehicle. Additionally, the intelligent vehicle may have knowledge of its route or end destination and be able to provide an explicit report to the stationary unit, indicating its immediate intentions at the intersection (e.g., proceed straight, turn left, etc.), as it approaches the intersection. 
         [0038]    In some embodiments, the roadside unit monitors the status of the traffic signal controlling access to the intersection, and performs right of way determination when detecting a disruption of the signal&#39;s functionality, an emergency, or any other appropriate condition. In some embodiments, the roadside unit performs right of way determination in the presence of a functional signal, to provide guidance in situations where right of way is not unambiguously indicated by the signal. Such a case is where a left-turning vehicle has a green light, but must yield to oncoming traffic. 
         [0039]    In some embodiments, to prevent the possibility of directing a vehicle into a dangerous situation, the system provides negative messages to vehicles not found to have right of way in addition to providing positive messages granting right of way. 
         [0040]    Note that for simplicity reasons, the disclosure assumes a typical intersection with two crossing perpendicular roadways. However, the present invention can be applied equally to other situations where intersecting traffic patterns cause a potential for collisions. Examples of alternate types of intersections include, but are not limited to, merges, traffic circles, driveways entering a roadway, and intersections with less or more than four entrances. 
         [0041]    It can also be seen, that though this invention has been described in the context of a public roadway, alternate embodiments also represent the invention. For example, the invention can be applied to maritime navigation systems, airport ground traffic, and industrial machinery. In these applications different rules stored in the system would govern the right of way determination and different factors, for example the weather in the airport case and the wind or water conditions in the maritime navigation case may be given different weights. 
         [0042]    In summary, while certain exemplary embodiments have been described above in detail and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive of the broad invention. In particular, it should be recognized that the teachings of the invention apply to a wide variety of systems and processes. It will thus be recognized that various modifications may be made to the illustrated and other embodiments of the invention described above, without departing from the broad inventive scope thereof. In view of the above it will be understood that the invention is not limited to the particular embodiments or arrangements disclosed, but is rather intended to cover any changes, adaptations or modifications which are within the scope and spirit of the invention as described herein.