Using APC-AVL Data to Improve Transit Reliability and Accessibility Analysis

Real-world transit service often deviates substantially from schedules, leading to variability in route-choice behaviors and experienced travel times that are not adequately reflected in existing accessibility analyses based on general transit feed specification (GTFS) schedule data alone. This study presents a methodology for more accurately assessing origin-destination (OD) transit reliability and accessibility by using GTFS data to generate candidate itineraries, then using automatic passenger counting and automatic vehicle location (APC-AVL) data to determine which routes are selected in real time and calculate the experienced travel time. The methodology is applied across March 2016-2020 from the perspectives of two groups in Allegheny County, Pennsylvania: residents in origins of high socioeconomic need traveling to opportunity employment hotspots, and prospective employers looking to establish a transit-accessible worksite. The worst OD pairs in practice achieved less than 15% of the accessibility captured by 95% of scheduled trips. At the 90-min threshold, the lowest observed accessibility corresponded to a realized loss of 17% of the eligible workforce due to service unreliability. These findings reveal the need to incorporate APC-AVL data to accurately model the route choice process and evaluate rider experiences.