Abstract:
Disclosed herein is a system for use on board a vehicle for receiving and indicating driving related signals, including the phases of traffic light signals to a driver of the vehicle. The system includes a receiver which responds to a plurality of driving-related signals including at least one transmitted signal representing a phase of a traffic light signal in proximity to the system. The system further includes one or more signal indicators coupled to the receiver output which indicate signals to a driver.

Description:
FIELD OF THE INVENTION 
   The invention relates to transportation safety systems, and more specifically to a system on board a vehicle for receiving and displaying driving-related signals such as traffic light signals. 
   BACKGROUND OF THE INVENTION 
   Conventional traffic light signaling at intersections only works well under good weather conditions. When sunglare or heavy precipitation are present, it can be difficult to understand whether a given traffic signal glows red, green or amber. Often under such conditions a driver will finally identify the traffic signal later than he or she should, with little time left to stop the vehicle when the signal glows red. During twilight periods, when eyes have difficulty distinguishing objects in the partially illuminated landscape, it can be just as difficult to understand when an intersection is being approached, and to watch for the presence of a traffic signal. In addition to these problems which affect all drivers, a significant number of drivers have red green color blindness which may impair their ability to distinguish between the conventional green light signal for “GO” and the conventional red light signal for “STOP”. Thus, under poor lighting or poor weather conditions, a driver may fail to stop before an intersection when the traffic signal glows red and thereby endanger himself and others. 
   Besides traffic signals, the driver must continually monitor other visual information. Even under the worst weather conditions, e.g. snowstorms, duststorms, fog, etc., the driver must understand the position of the vehicle in relation to the road and other vehicles. If the driver fails to understand the edge of the road and the vehicle veers off the road, a serious collision may result. At minimum, the driver may not be able to return the vehicle to the road. In such weather, when vehicles ahead of the driver slow down, a delay in perceiving such condition could lead to a serious collision. 
   Much needed driver information presumes keen and watchful perception on the part of the driver. The driver has must watch for and perceive visual events that appear with only a moment&#39;s notice. Road hazards, such as potholes and debris, pose serious risks to vehicles. Animals in the roadway, whether still or live, cause damage to vehicles and may cause vehicles to veer off the road. Caution and warning signs must also be perceived in time to be heeded. If vehicles approach a sharp turn or lane merge too fast, they may collide or veer off the road. 
   For all these reasons, an on-board vehicle signaling system is needed which complements external visual driver information by receiving and indicating driving-related signals such as the phase of a traffic stoplight being approached by the vehicle. 
   SUMMARY OF THE INVENTION 
   Accordingly, the vehicle on-board system of the present invention is adapted to receive and indicate driving-related signals including phases of traffic light signals to a driver of the vehicle. The on-board system includes means for receiving a plurality of driving related signals, the signals including at least one signal representing a phase of a traffic light signal in proximity to the system; and means for indicating the driving-related signals to a driver. 
   Preferably, the receiving means includes means for distinguishing a plurality of distinct signals and may include polling means which activate signaling devices external to the system, and the signaling devices are adapted to produce the driving related signals. The indicating means is preferably adapted to indicate all phases of a traffic light signal. The indicating means is preferably further adapted to indicate one of the red, green and amber light signals of a traffic signal using at least one light selected from the group consisting of blue, orange, brown or purple. The indicating means may preferably be adapted to verbally indicate the phases of a traffic signal, through, for example, an indicator light which bears a label such as “STOP”, “GO”, or “CAUTION”. 
   In addition to, or alternatively, the indicating means may be adapted to provide auditory indication of the phases of the traffic signal. By way of example, the auditory indication may include a voiced verbal message. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates a possible use of the on-board vehicle receiving and indicating system in connection with traffic light signaling. 
       FIG. 2  is a block diagram illustrating circuitry for transmitting traffic light signals for reception by on-board vehicle receiving system. 
       FIG. 3  is a block diagram illustrating an embodiment of on-board vehicle receiving and indicating system. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  illustrates a possible use of an embodiment of the invention for receiving and indicating traffic light signals on board a vehicle  10  approaching a traffic signal  12 . Distinguishable signals, for example radio frequency signals, are transmitted towards vehicles approaching the traffic signal  12  in connection with traffic light signals which are illuminated by traffic signal  12 . A signal receiving and indicating system  14  on-board vehicle  10  receives the transmitted signals and indicates the signals to the driver of the vehicle. 
   The signal receiving aspect of the invention may be realized in a number of ways. In the example described as follows, radio frequency signals are transmitted in connection with the traffic light signals, the radio frequency signals being received by the on board vehicle receiver/indicator system  14 . However, another way to transmit and receive signaling is through light, e.g. from narrowband sources, especially infrared LEDs and infrared lasers 
     FIG. 2  illustrates a possible signal transmitter  30  implementation for transmitting signals indicating traffic light signal phase for reception by the on-board vehicle receiving system  14 . As background to the invention, it will be understood, a traffic light signal controller  20  for a conventional red-amber-green traffic light signal outputs a group  27  of lamp controls  21 ,  22 , and  23  for timing the illumination of red, amber, and green lights at the intersection from two directions in the line of one road, for example, east and west. At the same time, the signal controller  20  outputs a group  28  of lamp controls  24 ,  25 , and  26  for timing the illumination of the red, amber and green lights in the other two directions, e.g. north and south, in the line of the intersecting road. As is known, the lamp controls  21  through  26  are generated by signal controller  20  through use of a timer  19 , alone, or together with certain inputs  16  . . .  18 , e.g. road vehicle sensors, and pushbutton input from pedestrians, etc. It will be understood that only one lamp control can be active at a time in a group  27  or  28  while the other two lamp controls are deactivated, such that only one lamp, e.g. the red lamp, is illuminated, while the green and amber lamps are turned off. 
   Lamp controls  21  through  26  are input to a signal generator  32  of signal transmitter  30 . Signal generator  32  simultaneously generates at least two orthogonal signals  34 ,  36  for transmission to vehicles. One signal  34  modulates an RF carrier from oscillator  38  via mixer  35  for transmission over a first pair  40  of directional antennas, one directional antenna transmitting, for example, in the north direction of a road traversing the intersection, and the other directional antenna transmitting in the opposite direction of the road, i.e. south direction. Signal  36  modulates RF carrier from oscillator  38  via mixer  37  for transmission over a second pair  42  of directional antennas in the directions of a second road traversing the intersection. Each of signals  34  and  36  preferably change with the phase of the traffic signal  12  such that “STOP”, “CAUTION” and “GO” signals are transmitted over respective pairs  40 ,  42  of directional antennas in phase with the red-amber-green light signals of traffic light signal  12 . 
   The traffic signal phase information of a signal  34  or  36  must be reliably and unmistakably distinguished time after time with little chance of disruption from unintentional, internal or external sources of signal interference. Accordingly, signals  34 ,  36  may comprise different tones. Alternatively, signals  34 ,  36  may comprise pulse sequences of varying information content. 
   The signal receiving and indicating system  14  on-board a vehicle will now be described, with reference to FIG.  3 . As shown in  FIG. 3 , transmitted signals  52  are picked up on an antenna  54 , which may be the vehicle&#39;s existing radio antenna, the car&#39;s body, or a special antenna attached only to system  50 . Signals from antenna  54 , after being bandpass filtered, are provided to fixed gain amplifier  56  and then to mixer  58  for downconversion using RF frequency from oscillator  60 . The downconverted signal is provided to detector  62  which discriminates the received signals and outputs them, to indicator lamps verbally labeled “STOP”, “CAUTION”, “HAZARD” and “GO”. Only one of “STOP”, “CAUTION” and “GO” lamps of system  14  will be illuminated at a particular time, according to the phase of traffic signal  12  in the direction the vehicle is traveling. For example, when the red signal light is illuminated at traffic signal  12 , the corresponding RF signal is received from transmitting system  30  on board the vehicle system  14  and the indicator lamp of system  14  which is labeled “STOP” is illuminated. Similarly, when the amber light is illuminated at traffic signal  12 , a different signal is transmitted from system  30  and received on board the vehicle by system  50 , which then illuminates the indicator lamp labeled “CAUTION”. When the green light is illuminated at traffic signal  12 , yet another signal is received by on board vehicle system  50 , and the indicator lamp of system  14  which is labeled “GO” is then illuminated. The “HAZARD” indicator lamp is in addition to the indicator signals which correspond to the red-amber-green traffic light signal. The “HAZARD” indicator lamp can be illuminated upon receipt of a signal indicating a nearby road hazard, stopped traffic condition, or reduced speed limit due to special circumstances, e.g. severe weather condition or school zone active period. 
   Preferably, the indicator lamps of system  14  are also color coded to further aid in the driver&#39;s immediate perception thereof. Since most drivers obtain best perception with a conventional color scheme, the “STOP” lamp is color-coded red, the “CAUTION” lamp is color-coded amber and the “GO” lamp is color-coded green. It will be understood that such color coding can be accomplished by installing colored lenses over incandescent lamps, or alternatively, using colored light emitting diodes directly. 
   However, a significant number of drivers suffer from red-green color blindness. For such drivers, it is often difficult to distinguish between the conventional red and green colors used on traffic light signals to indicate “STOP” and “GO”. System  14  includes optional lamp settings or, alternatively, optional lenses that permit different choices of colors to help color-blind drivers best distinguish differences between the indicated signals. For example, the color blue can be used instead of green to indicate “GO.” Other colors, for example, orange, brown or purple, may be used instead of one or more of the conventional traffic signal light colors, to help ensure best perception. 
   Receiving and indicating system  14  preferably includes an audio control unit  64  responsive to the separated signal output of detector  62  and loudspeaker  66  for providing auditory indications to the driver. Auditory indications can be nonverbal signals such as beeps, hums, etc. or voiced verbal messages that simulates or plays back human voice commands. For example, when approaching a traffic signal  12  that is glowing red, the audio control unit  64  will output a voiced verbal message of “STOP” over the loudspeaker  64 . Similarly, when the traffic signal  12  is glowing green, a voiced verbal message of “GO” is output. 
   In addition to the above functions, the receiving system  14  may also have a collision avoidance feature which automatically stops the vehicle when approaching the traffic signal that is glowing red (signaling “STOP”) at an excessive speed. The collision avoidance feature is implemented by a collision avoidance (CA) control unit  68  which receives “STOP” indicator input from detector  62  and an input from the vehicle representing its speed. Output from control unit  68  is provided to the vehicle&#39;s antilock braking system (ABS). A typical antilock braking system electronically varies the hydraulic pressure at the brake wheel cylinders many times a second to avoid wheel lock-up. However, a vehicle&#39;s ABS is typically only engaged by a fully depressed brake pedal, and once engaged, braking proceeds very rapidly, such that unsecured objects in the vehicle may be thrown forward. The CA feature of the invention contemplates use in connection with an ABS that can be engaged electronically, i.e. without requiring the brake pedal to be depressed, or fully depressed. Such ABS may also provide a second gradual stopping mode, for use when vehicle speed is only somewhat over limit. In such gradual mode, the ABS cycles the hydraulic pressure to a reduced pressure which is below the maximum pressure used for making sudden stops.