Expressway Exit Speed Limit Scheme Based on Smooth Speed Transition
The study of the grade-by-grade speed limit scheme that can meet the smooth transition of exit vehicle speed is of great significance to the smooth operation and safety enhancement of vehicles in the exit area.The unmanned aerial vehicle was used to collect the vehicle operation parameters of the highway exit,analyze the exit vehicle operation characteristics,consider the driver's cognitive response to the adjacent speed limit signs,construct a continuous speed limit sign setting spacing calculation model,establish different levels of speed limit schemes for the highway exit,and analyze and evaluate the designed different speed limit schemes by using driving simulation tests.The calculation results of the model show that the calculation results of the model show that the spacing of speed limit signs for 60-40 km/h is 160 m secondary speed limit scheme.The spacing of speed limit signs for 80-60-40 km/h is 300 m and 80 m in three level speed limit scheme,and the spacing of speed limit signs for 90-60-40 km/h is 300 m and 85 m,respectively.The spacing of speed limit signs for 100-80-60-40 km/h is 295,160 and 80 m in four level speed limit scheme.The model results were verified using a driving simulator,and the test results show that with the increase of the speed limit level,the vehicle dispersion amplitude decreases significantly,which indicates that the speed limit level by level scheme has obvious control effect on the exit vehicle running speed.The average deceleration index of the speed limit level by level scheme is less than 1.3 m/s2,which is all within the driving comfort.The four-level speed limit scheme can make the standard deviation of vehicle speed,average deceleration speed and shunt nose operating speed V85 controlled at 5.23 km/h,0.52 m/s2 and 54 km/h respectively,which greatly meets the requirements of smooth transition of vehicle speed.It can be seen that the step-by-step speed limit scheme can significantly improve the smoothness and safety of the exit speed transition with the help of the model quantitative optimization.
traffic safetymotorway exitsstep by step speed limit schemecontinuous speed limit sign spacing calculation model
万方数据
维普
