Does Every Trip Need to Be On Time? Multimodal Scheduling Performance Parameters with an Application to Amtrak Service in North Carolina

One of the challenges faced by transit service schedulers is how to set realistic running times for a route with a given set of performance parameters. On-time parameters consist of two components – the definition of what makes a trip “on-time,” and the desired percentage of trips that should meet the definition. This paper examines the on-time performance parameters used by three transportation modes: public transit systems, airlines, and Amtrak. These parameters range from an on-time window of no more than 5 minutes late for public transit systems, to 30 minutes late for long-distance Amtrak trains. While these times are divergent, compared to the average passenger trip duration the public transit window is 24.0% of the trip duration, while Amtrak’s window is only 7.6% of the trip duration. Not all modes have established a desired percentage of trips that should arrive on-time. The Transit Capacity and Quality of Service Manual creates a level-of-service (LOS) scale for on-time percentage, ranging from 95% or better on-time for LOS “A”, to 75% on-time for LOS “E”. Amtrak’s target depends upon the type of train with a target of 70% for long-distance trains to 95% on-time for commuter services. The overall target percent is 85% on-time. No published targets were identified for airlines. The paper concludes with an example application of the criteria to two Amtrak trains within North Carolina. This application shows that to achieve LOS “A”, more than 30 minutes of additional running time is required than to achieve LOS “E”.