A Safety Analysis Method for Highway Based on Average Speed

Traffic safety influenced by vehicles average speed and speed standard deviation was studied based on statistical data of several typical highways in China. The mechanism of road accident rate influenced by vehicles average speed and speed standard deviation was analysed firstly, then the partial correlation analysis between accident rate and average speed, speed deviation, coefficient of speed standard variation were conducted respectively based statistical data.The computed results show that the accident rate is most correlative with speed deviation, so the speed deviation is the key factor which has influence on traffic safety. Then, the critical value of speed deviation of same type highway was put forward based on quality control method. The analysis results shows that, when vehicles average speed is lower than that of designed, speed deviation control is important to decrease road accident rate.