METHOD FOR THE DETERMINATION OF TRAFFIC JAMS AT UNSIGNALED CROSSING

摘要

A method for the determination of traffic jams at unsignaled crossing is based on scanning intersection zone with two unidirectional laser beams from point above its geometric centre by means of taper double-beam scanning, wherein second beam is formed in plane with first beam, but with bias at half-period by scanning circle, and inclinations of optical axes of first and second beams are changed alternately in each scanning period in such a way that radius of second concentric circle at entry and of the controlled zone exit and is decreased by specified value. Determined is a vehicle type and driving direction by each traffic lane and delay thereof at the controlled zone at entries to intersection by minor highway with account of driving time of each specific vehicle. Thereafter a real time of intersection passage by each vehicle from traffic lanes of minor highway is determined by moment of crossing by vehicle rear bumper of one of scanning circles at stop-line region at intersection entry, and then by crossing of one of remote circles at intersection exit with calculation of traffic delay of intersection zone passage as difference between real time of passage and time of passage of this zone by each vehicle in specified direction without delay. The total traffic delay by each lane of minor highway is determined as sum of traffic delays of vehicles crossing controlled zone over selected time period and traffic delays of vehicles passing the intersection zone, and traffic delays by lanes are calculated as difference between real time of passage and time of passage of intersection zone without delay with account of vehicle type and driving direction of those vehicles that passed intersection zone during measurement time. The real passage time of all zones of intersection is determined with high accuracy by scanning period simultaneously by all lanes at intersection entries, this makes it possible to determine average delay by all lanes and at intersection in whole during any measurement time.