Abstract:
A traffic priority defining system implemented by emergency vehicles at an intersection. A signal, designated the second electronic signal, post emanation, is electronically verified as to source and sent to the controller for a traffic control device, such as a tricolor traffic light, to override the primary signal operating the traffic light for opposing traffic. One of the colored lights, usually yellow, is actuated to a second operational mode, to display an icon of an emergency situation. The specified color light&#39;s incandescent bulb resumes normal full to yield a yellow glow at the proper time.

Description:
[0001]    This application discloses and claims subject matter disclosed in my earlier filed provisional application, Serial No. 60/443,617 filed Jan. 29, 2003. 
     
    
     
       FIELD OF THE INVENTION  
       BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates to a traffic control system and to an emergency vehicle warning apparatus included therein.  
           [0003]    Emergency vehicles have a need to speed through intersections on their way to respond to situations. If the emergency vehicle on a main street is to avoid the necessity of having to slow down at every intersection to avoid colliding with vehicles when approaching from the intersecting streets, an effective warning must be provided of the presence of the emergency vehicle to such traffic on the intersecting streets.  
           [0004]    Many prior art devices have been provided for this purpose. In many of these patented and unpatented devices a transmitter is included in the emergency vehicle to provide a signal. A receiver is located to detect the signal transmittal from the emergency vehicle. The receiver actuates a control circuit that activates a signal device.  
           [0005]    Often the signal is an additional device built into or on the traffic light. Some systems also provide audio signals for pedestrians and vehicles. Others comprise rotary flashing lights. Still other systems trigger warning signals in devices that have been installed in nonemergency vehicles. These systems all require structure to be retro added either to vehicles or to the traffic light. This is both costly to a requirement to have new specially made traffic light fixtures which are not “off the shelf” increases the costs of such a signal system and decreases its likelihood of adoption by a municipal authority. Such systems also require custom transmitters for the emergency vehicles and receivers to cooperate with them.  
           [0006]    There is a need therefore for a different way to solve the problem at minimal cost to the political entity thus this invention.  
           [0007]    For a fuller understanding of the nature and objects of the invention, reference should be made to the following detailed description, taken in conjunction with the accompanying drawings.  
         SUMMARY OF THE INVENTION  
         [0008]    It is a first object to provide a traffic vehicle control system which incorporates an emergency warning means which is readily integratable with existing traffic control systems.  
           [0009]    It is a second object to provide a traffic control system that can be integrated into a transit vehicle priority system.  
           [0010]    It is a third object to provide an effective emergency warning signal which maybe readily retrofitted into existing traffic light structures.  
           [0011]    These and other objects of the invention will be set forth in detail herein and will be shown in the drawings as well as being set forth in the appended claims.  
           [0012]    Briefly stated there is provided in the present invention, an emergency traffic vehicle warning apparatus defined within a traffic control system. As is known, emergency vehicles are equipped with AVI (automatic vehicle identification) transmitters, the presence of which may be detected by loop antennas, such as those included in transit priority systems. The receivers of the special signals from emergency vehicles communicate with an automatic controller that operates a traffic signal to the green for the emergency vehicle or red for traffic. The automatic controller is programmed to provide a second output signal to the traffic signal indicative of an emergency warning condition, when the signal is sent to operate the emergency warning signal.  
           [0013]    The emergency warning signal of the present invention includes a two-state display. The display alternates between first and second states in response to the emergency signal. A first state may comprise a conventional traffic light display, namely, a colored circle of light. The second state may comprise a display of a specific symbol to depict an emergency situation. In a preferred form, the display comprises a matrix. The matrix is preferably included in a circuit package which may be disposed in a traffic light unit lamp socket to thereby provide for easy, low-cost retrofitting of conventional previously installed traffic signals.  
       
    
    
     BRIEF DESCRIPTION OF FIGURES  
       [0014]    [0014]FIG. 1 is a block diagram that represents a traffic control system which incorporates the present invention.  
         [0015]    [0015]FIG. 2 is a block diagram illustrating the connection of the traffic system controller to the emergency warning signal circuit.  
         [0016]    [0016]FIG. 3 is an illustration of the emergency warning display disposed within a traffic light.  
         [0017]    [0017]FIG. 4 illustrates a traffic light matrix energized into a second state.  
         [0018]    [0018]FIG. 5 illustrates the pattern displayed to drivers by the grid of FIG. 4.  
         [0019]    [0019]FIG. 6 is an isometric illustration of a warning signal retrofitted into a conventional traffic light.  
         [0020]    [0020]FIG. 7 is a flow diagram illustrating operation of the present invention.  
         [0021]    [0021]FIG. 8 is a signal light of a tricolor traffic signal having two different color LEDs therein.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0022]    [0022]FIG. 1 is a block diagram illustrating a transit control system which includes the present invention. An Automatic Traffic Surveillance And Control center (ATSAC center)  1  manages an Automated Traffic Control System (ATCS) referred to hereinafter as  2 .  
         [0023]    The ATCS  2  may be distributed over a city or other larger or smaller geopolitical region. The ATSAC center  1  may be coupled to and under the supervision of a control center  3 . The control center  3  may comprise a Transit Authority Control Center, Department of Transportation or other control entity. An example of such a transit priority system is the transit priority system of the Los Angeles Department of Transportation. The ATSAC center  1  includes an ATCS server  10  which interacts with a central communications hub  12 .  
         [0024]    A Transit Priority Manager Server  14  may be supervised from the control center  3  and provided with such information as daily schedule updates. The transmit priority manager server  14  monitors compliance of particular buses with their schedules and provides particular priority requests via the central communications hub  12  to the ATCS system  2  as are needed to monitor schedules. The ATCS server  2  monitors bus priority established by the transmit priority manager server  14  and issue ATSAC control commands to the central communication hub  12 .  
         [0025]    An ATCS system,  2  comprises a plurality of field communication hubs  20 . Each field communication hub  20  interacts with the central communication hub  12  via an ATSAC communications trunk  22 . While only one is shown, the use of a plurality is contemplated. Each field communications hub  20  communicates with a traffic controller  30 . Traffic controllers are well-known systems made by ______ and ______ respectively, such as model 2070 or model 2170. The model 2070 utilizes VME hardware utilizing standard VME (Virtual Machine Environment) interface modules and off the shelf software provided by ______. Programming and operation of the controllers is well known in the art. Each traffic controller  30  can control one or more traffic devices  35 . In the present depiction, the traffic device  35  controlled is a conventional traffic signal light  40  comprising a green light  42 , yellow light  43 , and red light  44 .  
         [0026]    Each traffic controller  30  receives an input from at least one AVI (Automatic Vehicle Identification) receiver  50  which detects the presence of a vehicle by means of its loop antenna  52 . The AVI receiver  50  and loop antenna  52  are as noted well-known devices. Commonly, the antenna loop  52  is placed in a  1 / 4  inch wide long slot that has been sawn in a street and sealer is placed over the antenna to protect it. Commonly, the antenna  52  response to a signal from a bus  54  which has an AVI transmitter  56 . The AVI transmitter  56  is also a well-known prior art device which automatically and continuously transmits a uniquely coded signal designated signal “A”. The AVI transmitter  56  while normally installed on the underside of the vehicle in reality is shown here for simplicity on the side of the vehicle. In accordance with the present invention, an emergency vehicle  60 , in the present exemplification, a fire engine  60 , is provided with an AVI transmitter  56 . The transmitter  56  is provided with a code that is programmed in the ATCS server  10 . The transmitter from the emergency vehicle put forth a signal “B” when needed.  
         [0027]    [0027]FIG. 2 is a block diagram which depicts the interaction of the emergency vehicle  60  and the traffic control system  2  to operate the traffic light  40  and other similar devices  35  when an emergency arises. Approach of the transmitter  56  of the emergency vehicle  60  putting forth signal “B” is sensed by the antenna  52 , which provides an input signal to the receiver  50 . The traffic controller  30  decodes the identity of the emergency vehicle  60  and communicates with the field communications hub  20  to determine if the code transmitted by the transmitter  56  is an authorized emergency signal “B”. In the normal state, the traffic controller  30  provides a first output indicated as being on a line  62  to operate the traffic signal  40  in its normal green-yellow-red mode as may be conventionally modified by signals received by bus  54 . When the traffic controller  30  senses an emergency vehicle  60 , different output, illustrated as being on a line  64 , is transmitted to the traffic signal  40  to provide emergency mod operation as further described below. The illustration set forth in FIG. 2 is for the purposes of describing operation or the system. It is possible that lines  62  and  64  in some embodiments will not be separate signals.  
         [0028]    [0028]FIG. 3 is an illustration of a typical traffic signal but modified as noted. In FIG. 3, a first version of a state of an emergency display is shown for one color of the traffic light, which is to be solely illuminated. In the preferred arrangement, this would be yellow light  43 .  
         [0029]    [0029]FIG. 4 is an illustration of the traffic light  43  of FIG. 3 embodied as a matrix of LEDs. An LED is a light-emitting diode. Normally traffic lights use a single white light that emits its light through a specifically colored lens or optimally a colored bulb or red, yellow or green can be used with a clear lens.  
         [0030]    Here, the matrix includes a large plurality of several hundred individual diodes behind a clear glass or polycarbonate lens. In normal operation, all or almost all of the yellow light-emitting diodes are operative for a signal “A” that transpires during normal nonemergency operation.  
         [0031]    In a second version, as illustrated in FIG. 4, the light  43  displays an emergency symbol  71 . In order to conveniently provide the display, the yellow light  43  comprises a matrix  70  of specific individual yellow light-emitting diodes  72 . The light-emitting diodes  72  are arranged to have an outline approximating that of a circle in order to provide the yellow light display as illustrated in FIG. 3. But upon the occurrence of an emergency, selected light-emitting diodes  72  are illuminated at the same time to provide a display of an emergency symbol  71 . In the embodiment as illustrated in FIG. 4, the symbol indicative of an emergency signal is an icon representing an emergency vehicle. Other symbols can be used as may be desired. In a preferred form, the display alternates periodically between a first state and a second state, i.e., between a traffic color display and the emergency symbol  71  display. The emergency symbol  71  generated by the matrix  70  of “ON” LEDs  72  is illustrated in FIG. 5.  
         [0032]    In the alternative, if desired, a different color of light could be emitted by the selected diodes. For example, blue light diodes that remain nonactivated during normal operation of the yellow signal light could be employed. When the emergency occurs, the yellow full circle can alternate with the blue icon lights or the yellow can terminate and only the blue icon signal can be seen as a steady or flashing light as may be desired. Such choices are within the skill and judgment of the political entity.  
         [0033]    As noted further in FIG. 3, which is one form of the present invention, the green and red lights  42  and  44  comprise conventional single lamps, each behind a lens  75  in an aperture  73 . The yellow light  43  comprises the matrix  70  retrofitted into the traffic light  40 . FIG. 6 is a detailed partial view of FIG. 3 illustrating one compartment  78  having a cover  79  containing the yellow light  43 . The warning light assembly  80  of the present invention embodied in the yellow light  43  comprises a circuit board  81  and operational circuitry  82 . The circuit board  81  contains the matrix  70 . The circuit board  81  is coupled to the operations control circuit  82  via a cable assembly  85 , comprising a plurality of cables in a harness.  
         [0034]    The cable assembly  85  carries both power and addressing information to light the appropriate preselected light-emitting diodes  72 . The control circuit  82  may include power conversion circuitry  87  to take power previously designated for a lamp and use it to operate the control circuit  82  and matrix  72 . The control circuit  82  also includes a decoder  89  for interpreting the output of the traffic controller  30 ; see FIG. 1, to operate the matrix  72 , either in full or under signal B in the icon format.  
         [0035]    While the discussion has set forth the incorporation of the matrix of LEDs into the yellow traffic lamp opening, obviously the red or the green could be just as easily utilized instead.  
         [0036]    It is also to be seen that a different icon other than the car shown in FIG. 5 can be used as the emergency signal this symbol such as a five or six pointed star, an ambulance, fire engine, police car or even a red cross specifically for the red signal light could be used as alternate icons.  
         [0037]    In order to ensure geopolitical acceptance of this invention, especially during times such as the early 21 st  century when municipalities are strapped for cash for all but necessities, it is important to be able to retrofit this invention into existing traffic devices, as opposed to trying to persuade governing bodies to purchase new equipment.  
         [0038]    In order to retrofit the traffic light  40  with the warning indicator apparatus of the present invention, the lamp illuminating the yellow light  43  and its corresponding lens  75  are removed from the traffic light  40 . See FIG. 3. The circuit board  81  is mounted to the rear of the cover  79  central compartment closure  74  so that the matrix  70  is in registration with the aperture  73 . A fastener  91  seen in FIG. 6 projects through the circuit board  80  to support the circuit board to a standoff  92 , at each corner of the circuit board  80 . In this manner, the circuit board  80  is supported to area surface of the central lighting component closure  74 . The control circuit  82  is mounted in the central lamp chamber  71 . As illustrated in FIG. 6, the control circuit  82  includes a fixture  94  to mount the control circuit  82  adjacent the area where a socket—not seen, would receive a lamp in a conventional embodiment is located. The matrix of LEDs  70  is seen in FIG. 3, but from the perspective of FIG. 6.  
         [0039]    The present invention thus provides convenient, cost-effective retrofit product to produce a new interactive system. The traffic light assembly  35  may be conveniently retrofitted as described above at reasonable cost. Emergency vehicle  60  may be conveniently fitted with AVI transmitters  56 . The ATS server at the central ATSAC center  1  may conveniently program each field communications hub  20  and local traffic controller  30 . Other variations and modifications are within the skill of the artisan. It is readily seen that the chosen light can just as easily be the red or green to be modified to include the matrix of this invention to display the icon of an emergency situation as may be desired.  
         [0040]    [0040]FIG. 7 is a flow chart which illustrates the operation of the present invention,  100 . At block  120 , the steady state operation is performed. Steady state operation includes normal operation of the ATSC  2  including operation of the traffic light and the granting of transit bus priority as discussed. At block  122 , an emergency vehicle  60  is detected by the AVI receiver  50 . At block  124 , the traffic controller  30  authenticates the identification of the emergency vehicle  60 , again per FIG. 1, and initiates an emergency warning. At block  126 , the emergency warning system, when in the present embodiment, is the yellow light  43 , is operated in emergency mode per the discussion of FIGS. 4 and 5. At block  128 , the current absence of an emergency vehicle is detected since the fire truck has moved through the specific invention and where the operation of the signal light returns to the steady state.  
         [0041]    The emergency warning indicator of the present invention may also be provided independently of an ATSC system  2 . Indeed there will be intersections where provision of emergency warning in accordance with the present invention will be highly useful but which intersections are not on transmitting routes. Here, the transmitter  56  and receiver  50  shown in FIG. 2 need not necessarily be an AVI transmitter and receiver that sense a signal from an antenna. Other known forms of transmitter and receiver may be used, such as a direct wired connection to change the matrix of a traffic signal  35  positioned adjacent a firehouse to the icon position as the fire truck departs the firehouse. The present invention may be used in other traffic control lights not included in a traffic control system. With the ease of retrofit in a traffic light housing and with the convenience in programming of widely used, conventional traffic controllers, the present invention can be cost-effectively deployed.  
         [0042]    Any means can be utilized for the implementation of the second signal. Mention may be made of rocker switches, slide switches, toggles and push buttons. The signals can be adjusted to work only close to the intersection, such as at  500  feet away from the controller, or for rural areas, it can be adjusted to work at about one half mile away.  
         [0043]    While the discussion has focused on the changing of the display of the matrix from a full circle glow, to the symbol of an icon indicative of an emergency, it is also to be seen that the second state of display can arise from the termination of a first color plurality of LEDs and the illumination of a second smaller plurality of LEDs within the same matrix. For example the majority of LEDs are yellow, with but a small amount being blue. When the second state is to transpire the yellow turns off and the blue turns on, all within the same light. See FIG. 8 wherein the Yellow glowing LEDs are designated “Y” and the blue glowing ones designated “B” It is also to be noted from FIG. 8 that the light of a signal need not be the customary round but can be a square of chamfered corner square as may be desired. Therefore the term full circle glow is used loosely and is not intended to specific denote a circular shape.  
         [0044]    While the discussion has centered on traffic tricolor lights, the invention also has applicability to combination semaphores and lights at railroad crossings and other traffic control devices.  
         [0045]    Since certain changes maybe made in the described apparatus without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.