| 摘要 |
A method for the determination of traffic jams at unsignaled crossing is based on recording vehicles entering controlled zone and leaving it by vehicle back bumpers with delay equal to average time of controlled zone passage by vehicles with determination of current length of vehicle queue at controlled zone and total traffic delay over measuring period by periodical accumulation with high frequency of each scanning period. At the end of each measuring period average traffic delay is determined by division of total traffic delay by total number of vehicles leaving controlled zone over the measuring period. Entry and exit boundaries of the controlled zone are formed by scanning intersection zone with unidirectional laser beam from point above its geometric centre by means of taper double-beam scanning. The optical axis of one of scanning positions is selected in such a way that laser beam describes a circle at traffic area of road intersection at stop-line region of all intersection entries, and second scanning beam forms exit boundary of the controlled zone. Scanning of intersection zone is performed simultaneously with two optical beams of laser scanning, and 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 allowing to determine 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 tine of passage without delay of intersection zone with account of vehicle type and driving direction. |
