Research On Dynamic Traffic Assignment Under Route Guidance Conditions

As the urban traffic congestion becoming more and more serious, route guidance has become an important way to alleviate the local traffic congestion and to improve equilibrium in road networks and efficiency of urban traffic system. Dynamic traffic assignment (DTA) is a kind of analyzing methods based on network supply and traffic demands in order to find the optimal network equilibrium which could support the traffic guidance and control.This paper employs link saturation to define the link status based on the classic road output flow model. An algorithm of DTA outputting the road status changing list is presented based on tracking the movement of each amount. Then the paper explains the input mode under practical circumstance by discrete periods and two-sequential method.Moreover, this paper discusses the impact of guiding information on route choices and proposes a VMS route guidance strategy about displaying the network’s future status, and then develops DTA algorithm under route guidance conditions by designing the double-scanning process and completes the corresponding simulation program.In a simulation case, twelve parameters have been classified into two groups:road properties and guidance properties. The effect of the VMS route guidance strategy about displaying the network future status in improving the network equilibrium has been analyzed under several different combinations of guidance property parameters. Finally, by analyzing and comparing DTA process to the greedy policy a concept in the DTA under guidance condition named the effective compensation range of guidance is proposed.