Impact of Buses on Highway Infrastructure: Case Study for New Jersey State

Buses are classified as heavy vehicles, and research has shown that heavy vehicles are mainly responsible for pavement damage and costs incurred to rectify the damage. Transit agencies must consider the pavement damage caused by a bus when choosing among different types of buses for procurement for certain corridors and deciding on the type of transit service for a corridor. Also, bus contribution to pavement damage should be considered in determining the appropriate amount of taxes and fees to be paid by this vehicle class. Currently, no tool exists to support such decisions. Pertinent literature was reviewed to determine the availability of methods for allocating roadway maintenance costs to buses. Two broad areas of highway impact–related literature, highway cost allocation studies and methods to estimate pavement deterioration resulting from vehicle–pavement interactions, were examined. A review of several state cost allocation studies showed that either equivalent single-axle loads (ESALs) or ESALS weighted by vehicle miles traveled were used to allocate pavement maintenance cost to various vehicle classes. Those studies, however, either accounted for buses by grouping them with other vehicles or did not account for them at all. Currently, no bus–pavement interaction models are available, although several mathematical and simulation models are available for truck-pavement interaction. Buses differ from trucks in load distribution, suspension, and travel characteristics. From results of the literature search a methodology, which uses industry standards and is minimal in data requirements, has been developed. With the use of data available in New Jersey, the application of this methodology showed that the maintenance cost attributable to buses in the state is about 2.4% of the total maintenance cost.