Applicability Analysis of a Line-Based Hybrid Transit System in Different Road Structures

The line-based hybrid transit (LHT) system is a public transit mode that improves transit performance by integrating the fixed-route transit service with a demand-responsive transit service. To facilitate the implementation and operation of such a hybrid transit system, this paper analyzes and compares the operating performance of the LHT system in two different road network structures: a rectangular structure and circular structure. To conduct a meaningful comparison, the generalized cost of LHT systems for both structures is formulated using the same analytical framework based on the continuous approximation approach. After constructing various time cost indicators related to system performance under two structures, the optimal design model is formulated as a nonlinear program, and an iterative enumeration method with vectorized programming is designed to solve it. A case study is performed to compare various cost components corresponding to the two structures, and sensitivity analysis is conducted. The results suggest that the LHT system is more suitable for operating in rectangular structures under low demand densities, while the system in circular structures is more suitable for operating under high demand densities. However, the performance of the LHT system in a circular structure is superior to that in a rectangular structure at most demand density levels for testing scenarios with high service area size or value of time.