A System Optimization Model of Traffic Divergence for Freeway Reconstruction and Expansion Considering Road Charge
Traffic divergence is an important measure to ensure the efficiency of traffic operation during the recon-struction and expansion of freeways.However,currently the expressway reconstruction and expansion projects in China mainly rely on the managers to determine the divergence measures empirically,of which the performance needs to be further improved.Meanwhile,there is lack of systematic and objective divergence methods.According to the road characteristics of regional divergence network,a road impedance function is developed by combining the impact of road toll on travelers'route choice with travel time.From the perspective of traffic managers,taking the minimum travel impedance of the road network as the optimization objective,the system optimization model of traf-fic divergence for reconstruction and expansion of freeway is established considering the balance of demand and supply,the relationship between path and link flows and the non-negative constraint of route flow.The Ka-rush-Kuhn-Tucker(KKT)conditions of the model is analyzed,and an algorithm based on gradient projection is de-signed to obtain the divergence path and path flow among origin-destination(OD)pairs in the road network.Taking a reconstruction and expansion project of freeway in Guangdong Province as an example,the traffic operation states of the entire road network and the construction section are modeled under three conditions of no divergence,diver-gence without road toll and divergence with road toll.The results show that:①Without considering the road toll,the average traffic volume of the section of reconstruction and expansion decreases by 27.72%,the saturation de-creases by 0.09,and the average speed increases by 4.26 km/h.②Taking road toll into consideration during the di-version,the traffic volume of the section of reconstruction and expansion is reduced by 44.8% on average,the satu-ration is reduced by 0.4,and the average speed is increased by 12.98 km/h.The road traffic efficiency is effectively improved,and the divergence does not cause deterioration of the traffic operation of other sections in the road net-work.Such conclusions confirm the effectiveness and superiority of the traffic divergence method proposed in this paper.
万方数据
维普
