Abstract:
Within the transit industry it is well known that transit buses have the potential to operate at weights that exceed vehicle weight limits. However, few attempts have been made to date to determine how often this occurs and to what degree. This research characterizes the current transit industry with respect to the regulatory environment, factors that have affected the weight of modern day transit buses, and methods for accommodating transit buses in pavement design. This research then develops and applies a methodology for calculating the in-service weights of standard 40-ft. transit buses using a combination of passenger characteristic data, transit bus curb weight data, and transit ridership data.
The findings of this research suggest that the transit bus industry is in a state of competing interests. Weight estimates developed in this research identify that current transit bus models are unable to comply with vehicle weight limits in most jurisdictions even with no passengers on board. Further, these estimates indicate that transit buses have a significant impact on pavements – comparable to those of fully-loaded, five-axle semi-trucks on a per vehicle basis. To date this issue has been addressed in the Canadian Prairie Region by indefinitely granting transit buses overweight permits. However, based on the current state of the transit industry there is little incentive for transit agencies to operate lightweight transit buses and little incentive for transit bus manufacturers to produce lightweight transit buses in order to address pavement and regulatory concerns. Consequently, transit bus axle weight issues in the Canadian Prairie Region are expected to continue in the foreseeable future.
