An exploration of the demand limit for flex-route as feeder transit services: a case study in Salt Lake City

As an innovative combination of fixed-route transit and demand responsive service, a flex-route operating policy had been introduced into feeder transit services. In this paper, a system cost function, combining vehicle operation cost and transit customer cost, is constructed as the performance measure to explore the feasibility of replacing the fixed-route policy with a flex-route policy in feeder transit systems, without disturbing the existing coordination between the major transit and feeder service. The Route F94 flex-route feeder system in Salt Lake City which connects with UTA TRAX Blue Rail Line is chosen for the analysis. The upper bound of demand for implementing the flex-route policy in this feeder service is derived. The results indicate that the Route F94 flex-route feeder system is still likely to have a distinct system advantage in operating environments with occasional request rejections, in comparison with the fixed-route service. As a result of our findings, it is possible to substantially expand the application of the flex-route policy in the feeder transit market