Research On Intersection Mode Selection Method In Urban Transportation Networks

Intersections are the nodes where vehicles change their directions and become the bottleneck of the network because of the conflicts of different traffic flow. There are various modes of intersection, such as signalized intersection, unsignlized intersection and interchange. Intersections in different modes organize traffic flow in different ways and have an important impact on traffic path selection and the overall operation of road transportation network. Therefore, it is necessary to research the problem of intersection mode selection in a road network.The analysis of intersection mode selection is based on the framework of existing road network. Considering the constraint of land use, this paper proposes the negative effect formulas of four intersection modes without extra road space. Based on this, two problems are studied:(1) the location selection of unsignalized and signalized intersection;(2) the location and mode selection of signalized intersection and overpass. To solve these two problems, this paper proposes a model which explicitly considers the interaction modes and traffic assignment respectively. Meanwhile, the proposed model is formulated as a 0-1 mixed integer bi-level programming problem, in which the upper level aims to minimize total network travel cost, while the lower level is a deterministic network user equilibrium problem that considers both vehicle delays and accident risk due to conflicting flows at intersections. At last, a heuristic algorithm based on genetic algorithm is developed to solve the proposed model, and numerical examples are presented to illustrate the effectiveness and validity the model.The results show that:(1) For the location selection of the unsignalized and signalized intersection, it is important to reasonably deploy traffic signal lights and decide signal cycle lengths so as to reduce the total user travel cost.(2) For the location and mode selection of the signalized intersection and overpass, reasonably choosing intersection modes can reduce the total user travel cost effectively. In addition, this model can also be a reasonable choice of the intersection modes selection under different types of investment budget, providing a method to understand the marginal utility of investment and determine the amount of investment.