Optimization of Transit Network to Minimize Transfers
While it is not possible to eliminate transit transfers in the existing fixed route services due to cost constraints, it is possible to reduce the number of transfers by adjusting the transit network configuration. It is also possible to reduce the waiting time at transfer points by coordinating schedules of different routes. The problem may be stated as determining a set of transit routes and associated frequencies, subject to a set of constraints, and achieving the desired objective(s) that minimizes the overall cost, which is generally a combination of user and operator costs. User costs are often captured by the total travel time incurred by users in the network and operator costs depend on the fleet size, transit vehicle size, transit vehicle miles, and vehicle hours required for a particular configuration. Constraints may include maximum allowable bus headway, load factor, and bus fleet size, etc. The solution of such an optimization problem is complicated because of the need to search for optimal solutions from a large number of possible solutions (which comprise a search space).
The goal of the research is to develop a methodology and a software tool for optimizing bus transit services to reduce transfers. The research objectives to be achieved include:
- Develop a methodology for optimizing transit service configuration based on a synthesis/refinement of the state-of-the-art and the state-of-the-practice. The methodology will have the ability to deal with a larger transit network than have been reported in the literature. Based on the methodology a more robust network optimization tool will be produced, which can be used for practical planning purposes.
- Develop a user-friendly computer tool for transit agencies to optimize their bus services with optimal transfers.