Transit Network Design Problem – Impact on Network Travel Time Using a Transportation Planning Model

Abstract

This research aimed to address a problem of the Transit-NDP with an upper level that optimizes the vehicles' Network Travel Time (NTT) subject to a budget constraint, and the lower level estimates vehicles' NTT based on a travel demand model (TDM), which involves identifying the optimal transit projects for reducing the NTT. The study objective is to explore the impact of a naïve model of the more complex Transit-NDP, where stakeholders suggest a group of potential transit projects. A complete evaluation of the enumeration and sampling search strategy is conducted for the two test networks. A sensitivity analysis is conducted on the impact of a demand increase for each test network. The Halle Network exhibits an almost constant NTT reduction ranging between 47.64% and 50.79% while the Karlsruhe Network exhibits a different behaviour with an NTT reduction ranging between 39.70% and 52.40%. In both networks, a set of candidate transit projects were members of the best solution for all test runs. The sensitivity analysis demonstrated that some candidate transit projects selected at lower budget levels, demand levels, or both were not necessarily selected as the best solutions at upper budget, demand levels, or both. In addition, the resulting dataset of the enumeration and sampling was utilized to develop a Random Forest regression model that produces estimates of the NTT with a success rate of 90%.