Study On The Minimum Security Following Distances Of Vehicles On Freeway

China’s highway mileage becomes the highest in the world since 2014 and enters a new stage in the 21 st century of rapid transit time. With the road network density and transportation increasingly balanced and convenient, while the freeway also have a highly accident rate which is mismatch with its high grade roads title. Rear-end collision accident always been the main form in freeway traffic accidents, mostly due to hypervelocity or unreasonable distance. With the background that speed control relatively mature、lack of distance maintain technology and vehicle performance increasingly rising, it is necessary to carry a deep study on minimum security following distances of vehicles on freeway, aims to make the distance control measures not only meeting the requirements of safe driving, and in accordance with the driver’s expectations, to improve highway safety level and quality of service from the fundamental.On the basis of official promulgation of traffic accidents, by studying the major cause of highway traffic safety problems and distilling the main factors affecting the highway smallest safety driving distance spacing, propose highway smallest safe driving distance mathematical model,which is based on the vehicle braking performance and driver’s expectations for the core. Originality proposed drivers’ reaction time of breaking varies with the speed and sufficient vehicles’ distance coefficient K through questionnaires combined with related research abroad. By the coefficient K, demarcating the threshold value of safety driving distance during different speed ranges, and verify by CarSim2016 platform. The results show that the consequents of this paper can better take into account the highway traffic safety and efficiency, providing a theoretical support to reduce the probability of rear-end collision from the point of the critical safety distance between vehicles. And also propose preventive strategies from operations management、drivers、vehicles、road and traffic environment five aspects and combination of speed—vehicle distance to avoid crash maximumly.