A methodology for choosing between fixed-route and flex-route policies for transit services

Flex-route transit brings together the low cost operability of fixed-route transit with the flexibility of demand responsive transit, and in recent years, it has become the most popular type of flexible transit service. In this paper, a methodology is proposed to help planners make better decisions regarding the choice between a conventional fixed-route and a flex-route policy for a specific transit system with a varying passenger demand. A service quality function is developed to measure the performance of transit systems, and analytical modeling and simulations are used to reproduce transit operation under the two policies. To be closer to reality, two criteria are proposed depending on the processing of rejected requests in the assessment of the service quality function for flex-route services. In various scenarios, critical demand densities, which represent the switching points between the two competing policies, are derived in a real-world transit service according to the two criteria. Copyright (c) 2014 John Wiley & Sons, Ltd.