Digging Latent Capacity For Bicycle Lanes In Congested Road Network

As a kind of green transportation mode,there is a revival of interest in traveling by bicycle.However,with decades of vehicle-oriented development,the road networks of the majority of cities are no longer friendly for cycling,which restrains the demand of traveling by bicycle.One option is to separate cyclists from motorists through exclusive bicycle lanes.This practice is easily implemented in uncongested traffic,However there may be some obstacles in enforcing on congested road network.Therefore,this project aims to develop a bicycle lane planning framework to satisfies the unfulfilled bicycle demand and promotes the revolution of green transportation.Early studies focused on the design of road network,but paid little attention to the design of bicycle lane network.Many scholars try to solve the problem of bicycle priority lane design(BPLD),but neglect the interaction between different modes and the impact of congestion.In addition,the application of early solutions in larger networks is limited.Moreover,domestic researches focus on the planning stage,which is easy to achieve outcome in the new area.However,little attention has been paid to the bicycle lane transformation of the old and congested road network.We articulated it as a discrete bilevel mathematical programming and developd a phases methodogy based on Branch-and-Boun algorithm to handle the real problem.The objective of the upper model is to minimize the total travel time,while the lower level is mainly the traffic assignment model.The objective function value of the upper level is determined by the lower level traffic assignment scheme.In order to meet the practical problems,the model not only concludes the congestion effect and interference of traffic in the network,but also sets traffic constraints and construction budget constraints for dedicated lanes.What's more,in order to solve the above model,this paper optimizes the algorithm based on Branch-and-Bound algorithm.Meanwhile,some algorithm is used for traffic assignment and Branch-and-Bound method is used for searching,which reduces alternative solutions and increases computational efficiency.The solution process is to give a bicycle lane setting scheme,then to calculate the traffic volume of each section by using the allocation model,and to calculate the total travel time according to the traffic volume of each section combined with the road performance function,so as to get the target of the upper model corresponding to the special lane setting scheme.The minimum value of the corresponding total travel time in the above scheme is the final solution,which is obtained through multiple searches.The methodology was tested on a improved classical network of 19 roads,1.69 km,for which the total of 3 road segments-equivalent to 0.29 km bicycle lanes were found.Hence,this paper appeals to policy makers that it can be greatly accommodated along with other modes even in the heart of the congested cities,which would help improve other related policies such as shared bicycle scheme and integration of public transport and bicycle.