Time Headway Distribution in Urban Expressway Merging Section Considering Velocity Division

摘要

Time headway is an important parameter in traffic flow theory and plays an essential role in many fields of traffic engineering. Based on the traffic flow data of the inner lane, the kerb lane, and the acceleration lane in the merging section of the second ring urban expressway in Chengdu, this paper proposes to divide the time headway into several ranges by using the interval velocity of vehicles. The log-normal model, the exponentially modified Gaussian model, the non-central F-distribution model, and the generalized extreme value model are used to fit the time headway of three lanes in each velocity range, and K-S test is used to determine the goodness-of-fit for each model. Finally, the division scheme of the velocity range is discussed, and it is found that reasonable adjustment for the velocity range division can improve the fitting effect of the model for the time headway.