Analysis on capacity of road traffic based maximum likelihood method

Capacity is different with impact of conditions of road, traffic and the operating. Therefore, capacity is a topic arousing general interest in the field of traffic flow theory. The paper aims to analyses statistical relationship between capacity and average headway. The first the average headway distribution based on the maximum likelihood estimation, then find the changes of average headway with occupancy, locate the minimum of average headway, thus obtained the road capacity. In the data processing we find a new distribution model of headway: log normal distribution model. By the empirical data testing, the calculation deviation of capacity is only 0.22 percent.