Performance of Pavements Subject to Higher Truck Weight Limits in Virginia

A study was mandated by Virginia’s General Assembly to determine if pavements in the southwest region of the state carrying vehicles operating under higher allowable weight limit provisions have greater maintenance and rehabilitation requirements than pavements bound by lower weight limits elsewhere. Detailed field surveys were conducted at 18 in-service pavement sites representing the range of roadway and traffic conditions found on Southwest Virginia’s primary and secondary highways. Traffic classification and weight surveys, an investigation of subsurface conditions, and comprehensive structural evaluations were conducted at all sites. The results were used to estimate the cost of damage attributed only to the net increase in allowable weight limits. Consistent with results of more comprehensive research conducted by and for other highway agencies, the authors found that pavement damage increased drastically with relatively small increases in truck weight for all vehicle classes affected by Virginia House Bill 2209. The cost of structural damage to mainline pavements attributable to the net weight increase in the seven affected counties alone was estimated at $28 million over 12 years. Costs for necessary improvements to roadway geometry, reduced service lives of bridges, increased motorist delays through work zones, and the safety implications of heavier vehicles operating in mountainous terrain were not included in the estimate. The report highlights the experience of one state highway agency with increasing political pressures to raise legal load limits.