Research On Urban Expressway Construction Sequence Based On Traffic Network Impact

With the rapid development of urbanization and motorization, the spatial scale of most cities in China continues to expand, and the city vehicle population continues to grow, leading to the main road network transport plane structure unable to meet the growing travel demand. Three-dimensional expressway traffic form has come into being in the form of viaduct and through the ground.As the framework of urban road network, urban expressway can guide urban spatial structure development affect people travel mode choice meet people travel demand in long-distance travel as well as the supply of traffic in a certain extent. It can ease the pressure on urban traffic in a given period. But as the large municipal projects, urban expressway construction cost is high and payback period is long. It cannot be constructed in one time with limited time, manpower and material resources, so expressway needs to be built in a certain sequence. Moreover, expressway, in the form of viaduct and through the ground, is difficult to construct and needs long construction period, surrounding road network also be effect by expressway construction. Due to the unreasonable sequence of the construction, urban traffic problems become serious and the city cannot develop healthily and orderly. Therefore, before the construction of the expressway, it is necessary to analyze and study the construction sequence, in order to promote the rational and orderly construction of the expressway.This paper analyzes the construction features and construction methods during the construction of expressway, and analyzes the traffic characteristics of each functional area within the construction area and the capacity of construction area deeply, in order to provide the basis for the reasonable determination of the traffic impact of expressway construction. In the next place, analyzes the traffic impact range and the traffic impact degree, through analysis of the driver’s traffic congestion acceptability, proposes a method to determine the extent of detour range driver driving the vehicle, and as it as the expressway road construction traffic impact range. By determining road traffic capacity, the measurement method of traffic impact degree is given by using the network cascading failure model.In the analysis of the expressway construction sequence, this paper divides expressway construction sequence into two parts on a macro and micro level, the sequence of road construction and the sequence of section construction. Taking into account the expressway travel benefit, construction difficulty level and construction project cost, builds roads construction importance index system and determines the construction importance of roads by TOPSIS method, proposes the method of sequence for expressway road construction. Next, proposes the meaning and division basis of construction section, divides expressway construction section by sequential clustering ideological, introduces the construction interval penalty coefficient to calculate the importance of construction section, gives section construction sequence.Finally, talking "two vertical and three horizontal" of Changchun City expressway system as the research object, according to the actual situation, the paper uses the proposed method to set the expressway construction sequence strategy.