Work in Progress:
Modelling modal choice: members of the PUC team have started this project developing a route choice model for public transit networks that incorporates variables related to network topology, complementing those found in traditional models based on service levels (travel time, cost, transfers, etc.) and users’ socioeconomic and demographic characteristics (income level, trip purpose, etc.). The topological variables represent concepts such as the directness of the chosen route and user knowledge of the network. For both of these factors, the necessary data is endogenous to the modelling process and can be quantified without the need for information-gathering beyond what is normally required for building route choice models. Other novel variables in the proposed formulation capture notions of user comfort such as vehicle occupancy rates and certain physical characteristics of network stations. We conclude that these new variables significantly improve the explanatory and predictive ability of existing route choice specifications.
Express services for BRT: Express services are essential on a BRT system, but identifying an optimal set of them is not trivial. Members of the PUC team have developed a methodology to determine the optimal combination of services (express, skip-stop, deadheading, short, regular) with their associated vehicle type and frequency. The approach penalizes transfers and incorporates capacity constraints and recognizes that users choose what is best for them. The model has been explored in several simulated scenarios identifying under which contexts express services provide a significant reduction in social costs (user costs plus operational costs). The team is working in extending this approach to a full network and in improving the optimization methodology. Also, a test on a bus corridor in Transantiago is expected for 2011.