The figure shows an intersection monitor that is a key subsystem of an emergency traffic-light-preemption system that could be any of the systems described in the three immediately preceding articles and in Systems Would Preempt Traffic Lights for Emergency Vehicles (NPO-30573), NASA Tech Briefs, Vol. 28, No. 10 (October 2004), page 36. This unit is so named because it is installed at an intersection, where it monitors the phases (in the sense of timing) of the traffic lights. The mode of operation of this monitor is independent of the type of traffic-light-controller hardware or software in use at the intersection. Moreover, the design of the monitor is such that (1) the monitor does not, by itself, affect the operation of the traffic- light controller and (2) in the event of a failure of the monitor, the trafficlight controller continues to function normally (albeit without preemption). The monitor is installed in series with the traffic-light controller at an intersection. The control signals of interest are monitored by use of high-impedance taps on affected control lines. These taps are fully isolated and further protected by high-voltage diodes that prevent any voltages or short circuits that arise within the monitor from affecting the controller. The signals from the taps are processed digitally and cleaned up by use of high-speed logic gates, and the resulting data are passed on to other parts of the traffic-light-preemption intersection subsystem. The data are compared continuously with data from vehicles and used to calculate timing for reliable preemption of the traffic lights. The pedestrian crossing at the intersection is also monitored, and pedestrians are warned not to cross during preemption.


    Access

    Access via TIB

    Check availability in my library


    Export, share and cite



    Title :

    Intersection Monitor for Traffic-Light-Preemption System


    Contributors:


    Publication date :

    2006-09-01


    Type of media :

    Miscellaneous


    Type of material :

    No indication


    Language :

    English




    Traffic light preemption management system

    GRIECO GIOVANNI / GUIDI BENEDETTA / LA PLACA MICHELANGELO et al. | European Patent Office | 2017

    Free access

    Traffic light preemption management system

    GRIECO GIOVANNI / GUIDI BENEDETTA / LA PLACA MICHELANGELO et al. | European Patent Office | 2017

    Free access


    Traffic-Light-Preemption Vehicle-Transponder Software Module

    Bachelder, Aaron / Foster, Conrad | NTRS | 2005