Strategic Network Expansion Of Urban Rapid Transit Systems

Rapidly developing urbans need an efficient way to release the heavy traffic congestion on road,and lots of cities choose to build the urban transit network.With the extension of city boundary,the expansion of rapid transit system based on the existing lines becomes an important issue in urban transportation system.In this thesis,the network expansion problem is formulated as a bi-objective programming model with the objective of minimizing the construction cost as well as maximizing total travel demand covered by the newly introduced transit lines.To solve the bi-objective mixed integer linear program,the approach called minimum distance to the utopia point is applied.Doing so,the certain tradeoff is suggested to the decision makers instead of a series of optimal solution needed to be considered.A real-world case study based on the metro network in Wuxi,China is conducted,and the results demonstrate the effectiveness and efficiency of the proposed model and the solution method.It is found that the utopia method can not only provide a reasonable connecting pattern of the network expansion problem,but also conduct the corridor selecting plan under the resource limited condition.After that,a new bi-objective model with the objectives of minimizing the construction cost and maximizing total OD demand in the whole network is formulated.The case based on the metro network in Wuxi is conducted,and four solutions are illustrated on the trade-off curve to show the effectiveness of the new model.The comparison of two model is made in both modeling and solving effectiveness.The travel demand model is suggested to apply when the network is large while the high calculating efficiency is required,and the OD data is hard to get.In contrast,the OD demand model is more tangible when the decision maker requires the network evaluation and owns all the OD data set.