Abstract:Relationship between freeflow speed and lane width is analyzed by studying characteristics of freeflow speed of urban road sections and exit lane at intersections.Field data of speed are collected from 9 roads with similar facility and different lane width in the urban area of Hangzhou by using video detection and recognition technology.The data show that the freeflow speeds obey the normal distribution, and the characteristic speed increases with the lane width.A model is established to describe the relationship between lane width and the speed discreteness.According to this model,the trend of speed discreteness is presented.The conclusion shows that reasonable value of lane width is beneficial to restricting running speed and improving road safety.This research also contributes in urban traffic flow modeling and traffic management.