Study On Network Design For Traffic Divergence During The Reconstruction Of Two-lane Highway

Reconstruction of two-lane highway is now an important way of freeway construction to save landuse and reduce cost. However, the ensurance of smooth trip is always a social focus as well as a technical problem.This paper will focus on some traffic problems related to reconstruction of two-lane highway, and make research on the network design and optimize for regional traffic divergence.Firstly, the regional fundamental highway network during construction period is sorted into three categories according to the reconstruction two-lane highway, and one of them is selected as the background of the research. The paper analyzes road characteristics and traffic characteristics of the reconstruction two-lane highway, rural highways, and other kinds of highways involved in the pointed network. The feasibility of diverged by rural highways is analyzed too.Secondly, the calculation method of highway capacity during the reconstruction is discussed as well as the adjustment factors. Based on the detailed analysis of the influence factors of highway capacity, the capacity of different construction segments of two-lane highway, two-lane rural highways, single-lane rural highways, and other highways are caculated by the adjustment coefficient method.According to the different influence the reconstruction two-lane highway has on trip, calculation method of trip during construction period is determined, including matrix split, matrix combination, and construction trucks'trip. Of which, the adjustment of elastic trip and trip of construction trucks is analyzed with emphasis.Moreover, the network design for traffic divergence during reconstruction period is researched based on the calibrated capacity of different kinds of highway segments as well as the the adjusted trip OD matrixes. The Bi-level programming model for network design problem is established , and the time-saving heuristic method is selected to solve this model.Lastly, the Suibei freeway(segment from Hailun to Beian) construction project in Heilongjiang Province is selected as the case to show the main steps of network design for traffic divergence during the reconstruction of two-lane highway to freeway. The divergence networks are designed at last for small cars and large trucks, respectively. The case study shows the feasibility of the bi-level programming model and the heuristic algorithm in solving network design problem for traffic divergence.