Abstract:
A computer controlled system for managing traffic signals at the intersection of at least two traffic lanes to avoid collisions between motor vehicles in intersecting lanes. An implementation for controlling traffic signals at the intersection to permit vehicles in each of the intersection traffic lanes a time period to pass through the intersection, detecting the presence of a vehicle in the intersection beyond the permitted time period, and responsive to a detection of the presence of the vehicle, controlling the traffic signals to stop other vehicles from passing through the intersection.

Description:
TECHNICAL FIELD  
       [0001]     The present invention relates to automated traffic control signal systems, and particularly to avoiding collisions when a motor vehicle is improperly blocking an intersection of two or more traffic roads or lanes.  
       BACKGROUND OF RELATED ART  
       [0002]     Automated traffic signal (light) systems have been in existence for almost a century. The art of automated traffic control is extensively developed. Some examples of conventional prior art are U.S. Pat. No. 3,688,254, issued in 1972, and U.S. Pat. No. 6,281,808, issued in 2001. It is well known that despite the increasing availability of computer controlled data processing resources over the past generation, annual traffic deaths in the United States still exceed 40,000. A good percentage of such deaths result from collisions at intersections of two or more roads or lanes. One of the reasons for higher fatality rates in intersection collisions is that the collision frequently involves a direct crash into a side of at least one of the vehicles. The side of a vehicle is the most vulnerable part of the vehicle. Until recently, standard automobiles did not have side airbags. Even now, when such side airbags are available, very few vehicles are equipped with them. To date, despite the extensively developed prior art in traffic control and, particularly, traffic control at intersections, collisions at intersections remain a leading cause of traffic deaths.  
       SUMMARY OF THE PRESENT INVENTION  
       [0003]     The present invention provides an advance in intersection traffic control that is easy to implement on existing vehicle traffic control apparatus and intends to reduce possibilities for collision when an automobile or other motor vehicle is improperly blocking an intersection of traffic signal controlled roads or lanes.  
         [0004]     The invention involves a computer controlled system for managing traffic signals at the intersection of at least two traffic lanes to avoid collisions between motor vehicles in intersecting lanes. An implementation is provided comprising the combination of means for controlling traffic signals at the intersection to permit vehicles in each of the intersecting traffic lanes a time period to pass through the intersection, means for detecting the presence of a vehicle in the intersection beyond said permitted time period, and means responsive to a detection of the presence of the vehicle, for controlling the traffic signals to stop other vehicles from passing through the intersection. The invention is applicable to traffic control systems having means for alternating said traffic signals to permit time periods to pass through for vehicles in each of the intersecting traffic lanes, and wherein the means responsive to the detection of the vehicle in the intersection extends the alternate time period for pass through of the vehicle until the vehicle is no longer present in the intersection.  
         [0005]     In accordance with a further aspect of the invention, apparatus for detecting the presence of a vehicle in the intersection is enabled to detect the presence of the vehicle of such predetermined time beyond the time period to indicate a stalled vehicle, and further including means responsive to such detection of a stalled vehicle to control the traffic signals in all intersecting lanes so as to prevent collisions with said stalled vehicle.  
         [0006]     There is another aspect of the invention including apparatus for dynamically predicting the potential presence of an approaching vehicle in the intersection beyond the time period combined with means responsive to this prediction of the presence of said vehicle for controlling the traffic signals to stop other vehicles from passing through the intersection. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     The present invention will be better understood and its numerous objects and advantages will become more apparent to those skilled in the art by reference to the following drawings, in conjunction with the accompanying specification, in which:  
         [0008]      FIG. 1  is a plan or map view above an illustrative intersection of a pair of one-way roads or lanes under normal flow with automated Stop/Go signal control;  
         [0009]      FIG. 2  is the plan intersection view of  FIG. 1  showing the response according to the present invention after a stalled vehicle is blocking the intersection;  
         [0010]      FIG. 3  is a plan or map view above an illustrative intersection of a pair of one-way roads or lanes with normal flow under automated Flashing signal control;  
         [0011]      FIG. 4  is the plan intersection view of  FIG. 3  showing the response according to the present invention after a stalled vehicle is blocking the intersection;  
         [0012]      FIG. 5  is a plan or map view above an illustrative intersection of a pair of two-way roads or lanes under normal flow with automated Stop/Go signal control;  
         [0013]      FIG. 6  is the plan intersection view of  FIG. 5  showing the response according to the present invention after a stalled vehicle is blocking the intersection;  
         [0014]      FIG. 7  is a block diagram of a generalized data processing system including a central processor unit that provides a very general illustration of the computer control of traffic signals in response to sensing apparatus as used in the present invention;  
         [0015]      FIG. 8  is an illustrative flowchart describing the setting up of the elements needed for the program of the invention for controlling traffic signals in response to a vehicle blocking a controlled intersection;  
         [0016]      FIG. 9  is an illustrative flowchart describing the setting up of the elements needed for the program of an aspect of the invention for controlling traffic signals in response to a vehicle moving toward an intersection at such a rate of speed that it is likely to be improperly blocking the intersection; and  
         [0017]      FIG. 10  is a flowchart of an illustrative simplified run of the program set up in  FIG. 8 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0018]     In  FIGS. 1 through 6 , there will be respectively illustrated plan or overviews of three different types of traffic signal controlled intersections. For each of the three illustrative intersections, there will shown a view under normal traffic flow and then a view with a vehicle blocking the intersection, together with an explanation of how the present invention adjusts for the blocking vehicle in each situation. The sensing of and programming to deal with each problem situation will then be subsequently described with respect to  FIGS. 8 through 10 .  
         [0019]     Referring now to  FIG. 1 , an intersection of two one-way roads  50  and  51  is shown. Vehicles  55  in each are moving or stopped in accordance with the status of respective controlled signal lights  52  and  53 . Arrowheads  54  point to the state of each of the signal lights. At this point in time, signal light  52  is in the Go state for road  50 , and consequently, signal light  53  is in the Stop state for road  51 . Each of the controlled signal lights are periodically alternated in conventional cycles.  
         [0020]      FIG. 2  shows the intersection of  FIG. 1  except that instead of a normal traffic situation, there is an automobile  56  stalled in the intersection. As will be set forth in greater detail hereinafter, automobile  56  is considered to be stalled since it has remained in the intersection beyond the change in signal permitting vehicles to proceed on road  50 . The present invention provides for a short time period to cover a vehicle such as automobile  56  racing through the intersection “trying to beat the light”. During this time, the Go state of traffic signal light  53  that normally should turn on as indicated by head  54  will be prohibited for a short time period dT. At the end of this short period, if the vehicle is still detected in the intersection as in  FIG. 2 , the vehicle will be considered to be stalled and the traffic signals in both directions,  52  and  53 , will be held at Stop until the stalled vehicle  56  is moved out of the intersection.  
         [0021]      FIG. 3  is an intersection of a pair of one-way roads or lanes, as in  FIG. 1 , under normal flow except that the traffic signals are under automated flashing signal control, e.g. both traffic signals  57  and  58  flash red requiring a vehicle  55  to make a full stop in both roads before proceeding through the intersection; or one or both of the road signals may flash yellow for slow and cautious crossing of the intersection.  
         [0022]      FIG. 4  shows the intersection of  FIG. 3  except that instead of a normal traffic situation, there is an automobile  59  stalled in the intersection. Automobile  56  is permitted a brief time period dT before it is considered to be stalled. During this time, the flashing states of traffic signal lights  57  and  58  may normally be turned on as indicated by heads  54 . At the end of this short period, if the vehicle  59  is still detected in the intersection as in  FIG. 4 , the vehicle will be considered to be stalled. The flashing of the traffic signals in both directions  57  and  58  will be prohibited and both the traffic signals  57  and  58  will be held at Stop until the stalled vehicle  56  is moved out of the intersection.  
         [0023]      FIGS. 5 and 6  are similar views and situations as  FIGS. 1 and 2 , respectively, except that instead of an intersection of a pair of one-way roads, the intersection is of a pair of two-way roads or lanes under normal flow with automated Stop/Go signal control. As in  FIGS. 1 and 2 , vehicles  55  in each in both directions are either moving or stopped in accordance with the status of respective controlled signal light pairs  65  and  67  or  66  and  68 . Arrowheads  54  point to the state of each of the signal lights. At the point in time in  FIG. 5 , signal light pairs  65  and  67  are in the Go state for two lane road  61 / 62 , and consequently, signal light pairs  66  and  68  are in the Stop state for two lane road  63 / 64 . Each of the controlled signal lights are periodically alternated in conventional cycles.  
         [0024]      FIG. 6  shows the intersection of  FIG. 5  except that instead of a normal traffic situation there is an automobile  69  in the intersection. As will be set forth in greater detail hereinafter, automobile  69  may be stalled since it has remained in the intersection beyond the change in signal permitting vehicles to proceed on road  50 . The present invention provides for a short time period to cover a vehicle such as automobile  69  racing through the intersection “trying to beat the light”, and as may be the case in  FIG. 6 , the vehicle  69  has been trying to make a left turn but has been unable to do so because of a constant flow of oncoming vehicles in lane  61 . During this time, the Go states of traffic signal lights  66  and  68  that normally should turn on as indicated by head  54  will be prohibited for a short time period dT. At the end of this short period, if the vehicle is still detected in the intersection, the vehicle will be considered to be stalled, and the traffic signals in both directions,  65 / 67  and  66 / 68  will be held at Stop until the stalled vehicle is moved out of the intersection.  
         [0025]     Referring now to  FIG. 7 , there is provided a diagrammatic view of an illustrative computer control system that may function to coordinate and control traffic signals at an intersection in the practice of the present invention. This control unit may be local at the intersection or it may be situated remote from the intersection as part of a more extensive regional traffic pattern control server. In either event, the functional elements will be equivalent. Conventional sensors  27  are positioned in dozens of places in predetermined patterns throughout the intersection. For aspects of the present invention they may be positioned in the roads, hundreds of yards from the intersection. The sensors may be embedded in the roads or positioned above the roads. Preferably, the sensors are some form of light sensors from which light patterns may determine which, in turn, may be interpreted to determine the presence of vehicles. Traffic sensor hardware is a well developed technology in the art. Sensors  27  are connected via I/O adapter  11  to a central processing unit  30  that, in turn, is interconnected to various other components by system bus  32  and coordinates the operations. An operating system  35  that runs on processor  30  provides control and is used to coordinate the functions of the various components of the control system. The Operating System (OS)  35  is stored in Random Access Memory (RAM)  31 . The programs for the various automobile monitor and control functions, including those of the present invention, may be stored in Read Only Memory (ROM)  33  and moved into and out of RAM to perform their respective functions. The information from sensors  27  may also be stored in a central storage unit  28  where it will be available for advanced diagnostics for traffic control. The control signal unit  43  is controlled by the processor  30  through traffic signal adapter  42 .  
         [0026]     Now, with reference to the programming shown in  FIG. 8 , there will be described how the system and programs of the present invention are set up. There is provided a conventional computer controlled system for monitoring traffic flow through a road intersection and for controlling traffic signals responsive to the monitoring, step  71 . Provision is made for predetermining and setting a time period that will normally permit a vehicle to pass through the intersection, step  72 . This predetermined period should take into account the situation and observed behavior of drivers at the intersection. For example, if the intersection is one at which drivers tend to try to “beat the light”, the time period should take this into account. If the intersection if normally clogged with vehicles waiting to make a left turn against traffic, the time period should be one after a switching of the light signals from Go to Stop, it should reasonably take into account the time it takes for the left turn vehicles to complete their turns. It is noted that this is a brief time period in addition to the alternate time period during which the respective Stop and Go signals control. Also, if the intersection is one with flashing signals, then the time period one that will permit a vehicle having the right of way in the intersection to clear the intersection.  
         [0027]     Provision is made for the sensing of the presence of a vehicle from one of the roads in the intersection, step  73 . Provision is made for signaling an alert, step  74 , when a vehicle has been sensed as being in the intersection in step  73  and is still in the intersection upon the expiration of the time period as set in step  72 . Provision is made for a response to an alert in step  74 , for controlling the traffic signals to stop other vehicles from moving through the intersection while the sensed vehicle remains in the intersection, step  75 . Also, while the vehicle remains in the intersection in a system having signal switching at alternate regular intervals, provision is made, step  76 , for an override of any Go signal to a Stop signal while the vehicle remains in the intersection. Also, while the vehicle remains in the intersection in a system having flashing Stop and then Go or proceed with caution signals, Proceed signal to a Stop signal while the vehicle remains in the intersection.  
         [0028]     Provision is also made for sensing that the vehicle sensed as being in the intersection in step  73  is no longer in the intersection, step  78 ; and there is provided in response to a vehicle clear sensing in step  78  for the resumption, i.e. resetting of traffic control signals to normal traffic control, step  79 .  
         [0029]     With reference to  FIG. 9 , there will be described, step  81 , another aspect of the system of  FIG. 8  for determining that a vehicle approaching an intersection is likely to be there beyond a time period set as in step  72 ,  FIG. 8 . Through appropriate in-road sensors and/or radar, the speed of a vehicle approaching intersection is determined, step  82 . Provision is made for a determination of the distance of the approaching vehicle from the intersection, step  83 . The data of steps  82  and  83  may be used in the calculation of the time that the approaching vehicle is likely to be in the intersection, step  84 . Finally, provision is made, step  85 , for using the calculation from step  84  to determine whether there should be an alert in step  74 ,  FIG. 8 , and upon such an alert to proceed according to steps  75  through  79 ,  FIG. 8 .  
         [0030]     Now, with reference to the flowchart of  FIG. 10 , a simplified illustrative run of the process set up in  FIG. 8  will be described. At a road intersection, a signal system with alternate switching signals at intervals T, step  87  is provided. An initial determination is made as to whether T has expired, step  88 . If Yes, a determination is then made as to whether the intersection is clear of vehicles, step  89 . If Yes, the signal is switched, step  94 , and the process returned to step  88  via branch “A”. If No, then there is a time-out commenced for the additional previously described predetermined time period dT, step  90 , during which a determination is made as to whether the intersection is now clear, step  91 . If Yes, the signal is switched, step  94 , and the process returned to step  88  via branch “A”. If No, a further determination is made as to whether the period dT has timed out or been completed, step  92 . If Yes, a last determination is made as to whether the intersection is now clear, step  93 . If Yes, the signal is switched, step  94 , and the process returned to step  88  via branch “A”. If No, then, step  95 , an alert is set, and signals are changed to Stop, step  95 . After this point, the intersection is sensed for the presence of the vehicle which is now presumed to be stalled, step  96 . If the vehicle is no longer in the intersection, then, step  97 , all Stops are cancelled and the process returned to step  88  via branch “A”.  
         [0031]     Although certain preferred embodiments have been shown and described, it will be understood that many changes and modifications may be made therein without departing from the scope and intent of the appended claims.