Maximizing Access in Transit Network Design

Recently published:

  • Rayaprolu, H., Wu, H., Lahoorpoor, B., and Levinson, D. (2022) Maximizing Access in Transit Network Design. Journal of Public Transportation. 24 [doi]

This study adopts an Access-Oriented Design (AOD) framework for optimizing transit network design. We present and demonstrate a method to evaluate the best combination of local and express alternative transit system designs through the novel concept of ‘iso-access lines’. Two bus network system designs were explored for a greenfield development in suburban Sydney: through-routed transit lines (T-ways) with higher speeds and more direct service, but longer access and egress times, and local routes that provide additional spatial coverage. We developed scenarios with T-ways only, local routes only, and both, and computed transit access to jobs as a cumulative-opportunities measure for each scenario. Local routes offer greater overall access, while T-ways provide greater access-per-unit-cost. The optimal combination of the two was established by generating ‘iso-access’ lines and determining access-maximizing combinations for a given cost by applying production-theory principles. For 15-min access, the optimal combinations had T-way service frequency equivalent to 0.48 times that of local routes. This ratio increased to 1.45, 2.05 and 2.63 for 30-min, 45- min and 60-min access respectively. In practice, the method can be applied to determine optimal transit combinations for any given budget and desired access level.

Fig. 4. Schematic representation of transit connections designed for the development area. T-ways connect superblock centers with rail stations on either end. Local routes originate at rail stations, loop around superblocks and terminate at the origin stations.