Research On Optimization Design Of Route Deviation Transit System

With the rapid development of economy,the level of urbanization and automation has been continuously improved.As a result,the contradiction between traffic supply and demand is sharpening.However,the development of public transport with the advantages of large volume,low pollution and low cost is slow.At the same time,there are some problems such as uneven bus coverage and poor flexibility in low-density suburban areas and low-demand time periods.Consequently,people rely heavily on private transportation,which further aggravates the problems of traffic congestion and environmental pollution.In order to meet people’s public travel needs in low-density suburban areas and low-demand time periods,respond to people’s diverse demand,and enhance the competitiveness of public transportation,route deviation transit was born.Route deviation transit is a kind of operation mode that different from conventional public transport,it combines the advantages of fix-route transit and demand-responsive transit.Hence,it not only has the characteristics of low cost and wide coverage,but also has the characteristics of flexible layout and strong service.It has proven to be a useful supplementary form of conventional public transport to effectively compensate for the blank areas and time periods where conventional public transport does not provide services.Firstly,this paper expounds the route deviation transit system,summarizes its scheduling form and function orientation,and proposes the optimization design steps of the route deviation transit system based on the conditions in China.Secondly,according to the study on slack time of the system,the calculation formula of distance between fixed stop is obtained.Meanwhile,sensitivity analysis of relevant parameters is carried out to explore the influence of the values on distance between fixed stop.Thirdly,the general method of demand stop layout and vehicle scheduling is studied on the basis of the operation characteristics of route deviation transit as well as the conditions in China,including demand stop location,demand stop layout optimization,vehicle scheduling model and other process to complete the optimization design of route deviation transit.Finally,the optimization design of route deviation transit method proposed in this paper is verified by an example in Cangzhou.Based on the confirmed distance between fixed stop,drawing lessons from traffic planning,the initial service area is divided into several transit quarters,combined with the principle of bus stop location to locate per demand stop in every transit quarter,and thus to determine the layout of demand stops in service area.At the same time,a layout optimization model for demand stops based on Thiessen polygon is built and a solving algorithm is designed to obtain approximate solution.Meanwhile,the vehicle scheduling model is established from two angles of enterprise operation cost and passenger travel cost to select demand stops that the system served.Based on night line data in Cangzhou,the route deviation transit line in the "West Railway Station-Wuhua Market" is designed using the optimization design method proposed in the paper.Not only weight of walking time is analyzed to research its influence on final result,but the utilities of route deviation transit and fix-route transit is compared to verify the rationality of the optimization design method.