The spatial distribution of bus garages decides the total vehicular deadhead mileage of the transit system because buses must travel between bus garages and terminals at the start or conclusion of a day. By contrast, the size of the garages determines the queuing status when buses enter or leave the garages. Thus, a bus garage system with reasonable distribution and size is required to address these problems. In this paper, a queuing-location-allocation model for optimizing a bus garage system is developed. Given nonlinear objective function is involved, a linearization technique is then introduced to convert the proposed model into an equivalent linear form. Next, a Lagrangian relaxation algorithm is designed to solve the linear form model. To validate the proposed algorithm, two groups of randomly generated test instances and a real-life case, the Dalian transit system in China, are applied. The impacts of several critical factors, including the required unit area per bus, the restriction on garages’ capacity, and the discount rate, on system costs, have also been examined. Results show that planners and transport managers should seriously consider these factors when designing an effective bus garage system.
|Publication status||Accepted/In press - 8 Jan 2021|
- bus garages
- deadhead cost
- queuing-location-allocation model
- Lagrangian relaxation