Influence Of Phase Conversion Prompt On Traffic Characteristics And Capacity At Intersection

Signal reversing prompt device has been applied to signalized intersections in many cities in China, and countdown is most commonly used. However there was no traffic rules regulate these signal lights in China so that the application of these lights is disordered and results in lots of traffic accidents. At present the effect of countdown in improving the intersection safety and efficiency have differences, and there are less research on intersections efficiency in our country about reversing prompt.This paper targets at typical intersections in Harbin, from the traffic psychology, efficiency and safety angles to study the impact of reversing prompt device. In the matter of traffic psychology, through the questionnaire survey, surveying the support rate of countdown device installation and the psychological possible behavior of driver in the countdown signal intersection. In the matter of efficiency and safety, based on video data, according to the road conditions and the intersection of phase control method, extract the start reaction time, headway, stranded vehicle rate in the weaving area during the yellow light and the red light running rate and other parameter, T-test method in SPSS software has been applied to acquire operating parameters, do significance analysis on impact of countdown. Based on the data of four indicators traffic accidents in recent ten years in Harbin, the paper analyses the effect of traffic safety of countdown. Finally, the paper applies VISSIM simulation software. Contrasts and analyses the traffic characteristic before and after the installation of the countdown. The simulation results show that:installation of countdown meter reduces travel time of vehicle, delay and queue number, improves the possible capacity of the intersection significantly.Installation of the countdown obviously reduces the driver starting reaction time, and advances the time of reaching the saturation headway, and improves the traffic operation efficiency; But it also increases the stranded vehicle rate during the yellow light and the red light running rate and the traffic accident number, has a negative effect on traffic safety. VISSIM evaluation results show that after the installation of a countdown clock, and the vehicle travel time is reduced by 11.63s, delay time is reduced by 19.05%, vehicle queue length is reduced by 12.58m, possible capacity increase by 2310pcu/h. The video analysis results show that 81.8% of the car drivers support the establishment of signal countdown device; and if the alarm time is over 31s, shut down the engine can reduce the pollutant emissions, and if the time id over 72s, shut down the engine can reduce the fuel consumption.