EFFECTS OF AUTOMATED SCHEDULING AND DISPATCH TECHNOLOGY ON PARATRANSIT SCHEDULE ADHERENCE IN SOUTHEASTERN MICHIGAN

Among the paratransit performance indicators likely to be affected by automated scheduling and dispatch (ASD) is schedule adherence. Schedule adherence refers to a variety of measures, such as on-time arrival at a trip pickup point, associated with how well paratransit buses adhere to daily trip schedules. Such measures, then, serve as indicators of how well the transit operator adheres to trip times promised to customers during the trip reservation process. This study evaluates the Suburban Mobility Authority for Regional Transportation's (SMART's) performance on several key schedule adherence measures based on a sample of paratransit trips selected from their daily paratransit trip logs. More specifically, this paper characterizes SMART's schedule adherence performance on eight measures, with a particular emphasis on evaluating their ASD's effects on schedule adherence. To isolate effects due to SMART's ASD system (Quo Vadis), the evaluators employed multivariate linear regression analysis, which allows for statistical control over other factors influencing service outcomes. The results of this analysis indicate that, holding constant for other changes and events affecting SMART paratransit operations, Quo Vadis-based schedules are associated with declines in per trip travel time, earlier than scheduled arrival at scheduled trip pickup times, later than scheduled arrival at scheduled drop-off times (as a whole suggesting some underestimation of required trip times in schedule creation), and fewer intermediate pickups and drop-offs during trips. Furthermore, the analyses also indicate that Quo Vadis has improved the scheduling of intermediate pickups, making those that are scheduled less burdensome in terms of time costs. On the other hand, Quo Vadis as used does not appear to allocate enough time for intermediate drop-offs, contributing to lateness relative to scheduled travel times. In sum, with Quo Vadis actual travel times have improved (suggesting better ordered schedules and resulting in faster trips for customers, on average), but Quo Vadis has been underestimating required travel times.