Effect of Passenger Encumbrance and Mobility Aid Use on Dwell Time Variability in Low-floor Transit Vehicles

Public transit serves users with a broad range of physical capabilities and design needs. However information about the operational effects of diverse users interacting with the transit system is scarce. This paper examined the occurrence and effects of boarding and alighting passengers with mobility aids (wheelchairs, scooters, walkers and canes), or with large items (carts, strollers, bicycles, or carrying an infant) on bus stop dwell time in a fixed-route bus service. On-board video data from low-floor public transit buses serving Ann Arbor, Michigan were used from 199 bus stops with at least one passenger boarding or alighting with a mobility aid or encumbered with a large item, and an additional 1642 bus stops without any mobility aids or encumbrances. A sequence of linear regression models examined the relationship between dwell time and the addition of variables representing passengers with mobility aids and encumbrances, and use of the on-vehicle access ramp, beyond explanatory variables typically used in dwell time analysis. Accounting for passengers boarding/alighting with mobility aids and encumbrances (p < 0.001) and use of the access ramp (p < 0.001) increased the variance explanation of a dwell time model based on boarding passengers by fare payment, alighting passengers by door use, and passenger load from 46% to 56%. Results indicate distinct patterns in the durations for boarding and alighting by passengers with vs. without mobility aids and encumbrances, and when a ramp is used by wheeled mobility users vs. ambulatory passengers with walking aids. The findings suggest that accounting for the presence of passengers with mobility aids or encumbrances and ramp use in dwell time analyses could help transit operators make their service operationally more efficient and inclusive for all passengers and encourage more use of fixed-route transit among individuals with disabilities.