Process for monitoring traffic for automatic vehicle incident detection

  • US 5,884,212 A
  • Filed: 10/15/1996
  • Issued: 03/16/1999
  • Est. Priority Date: 04/15/1994
  • Status: Expired due to Fees
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First Claim
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1. Process for monitoring the traffic of vehicles able to travel on at least two lanes, of the type consisting in transmitting a UFH wave of predetermined form in accordance with a predefined radiation pattern, in receiving signals reflected by the vehicles over a given duration of acquisition TA, and in processing the signals received in such a way as to detect the vehicles and in calculating, for each distance, the number of vehicles i detected as well as the instantaneous speed Vi (t) at a given instant t of each vehicle, the process wherein, the radiation pattern having an axis of aim substantially parallel to the direction of the lanes, and the steps of acquiring and processing the signals being iterated over consecutive time intervals, it furthermore includes an automatic incident detection phase comprising performing the following iterative steps:

  • A first step of calculating parameters including;

    investigating, at each instant t, whether a vehicle i detected in the current time interval corresponds to a vehicle j detected at an instant of the preceding time interval;

    for all the vehicles i corresponding to a vehicle j, calculating at the instant t, their acceleration γ

    i (t) by applying the relation ##EQU7## in which α

    t represents the duration between the instants and t, as well as a prediction ViP (t+1) of their speed at a time of the following time interval, by applying the relation
    
    
    space="preserve" listing-type="equation">V.sub.i.sup.P (t+1)=γ

    .sub.i (t)×

    Δ

    t+V.sub.i (t)for the other vehicles i, initializing their acceleration γ

    i (t) to the zero value;

    eliminating from the processing all the other vehicles j not corresponding to any vehicle; and

    A second step of incident detection based on the parameters calculated in the first step, by detecting the passing of the speed of a vehicle i below a first predetermined speed threshold Vthresh.

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