Study On The Conventional Public Transit System Evaluation And Network Optimation In Small And Medium-sized Cities

Public transit priority is considered to be an effective way to solve urbantraffic congestion, and transportation planning researchers has done a lot ofresearch on transit system evaluation and transit network optimization, but rarelyfor transit system in small and medium-sized cities. On one hand, the transit systemin small and medium-sized cities has developed without planning for a long term,which makes the network layout unreasonable and low level of service, the networkneeds optimization urgently. On the other hand, transit network in small andmedium-sized cities is smaller than that in large cities, and is easy to coordinatewith city land layout. Also, reconstruction of transit network in small and medium-sized cities has advantages of less investment and easy to access. The thesisspecifically studies on transit networks in small and medium-sized cities from thefollowing aspects:First, analysis the inhabitant trips characteristics and transit status of small andmedium-sized cities. Taking four small and medium-sized cities of Liaoningprovince as example, analysis urban residents’ trip features, with the intentionsurvey, summarizes the main problems of small and medium-sized urban transitsystem.Next is the research on evaluation of transit systems in small and medium-sized cities. Based on the characteristics of small and medium-sized urban transitsystems, selects indicators from two aspects of the network layout of rationality andthe level of transit service, and establishes the evaluation index system of a publictransport system for small and medium-sized cities. On this basis, uses AHP andyaahp software to calculate the relative weight of indicators. To determine themembership function of indicators, tries to find the distribution law by statistics ofsome small and medium-sized urban public transit system indicators, and use theMatlab fuzzy toolbox to build the membership function o f each indicator, andestablishes fuzzy comprehensive evaluation model for transit system in small andmedium-sized cities.Then raises a global optimization method based on optimum route selection forsmall and medium-sized urban transit network. By the actual situation of transitsystem in small and medium-sized cities, takes maximum unit benefit as theobjective function, and takes route length, non-linear coefficient, in-line passengercapacity, section non-equilibrium factor, the number of multiplexed lines andstation distance as constrains to establish transit network optimization model for small and medium-sized cities. In this thesis, the transit network optimization isdecomposed into four steps, namely the merger of bus stops, line origin anddestination stops selection and distribution, generation of candidate set of bus lines,and optimum route selection. And uses the Hungarian algorithm to solve line originand destination stops selection and distribution problem, uses Yen algorithms tosolve generation of candidate set of bus lines, brute-force method is used to solveoptimum route selection. For each algorithm, C++program is designed and put intouse. With the decomposition of optimization model, it is easier to find solution andplanners can add their own experience and make manual adjustmentsFinally, takes FuXin city as example, conducts a comprehensive evaluation forexisting transit system, and optimizes the transit network of its main area. Throughthis case, verifies that the proposed evaluation method and transit networkoptimization method for small and medium-sized cities is not only scientific intheory, but also workable in practice.