Preservation of Infrastructure by Using Weigh-in-Motion Coordinated Weight Enforcement

The Montana Department of Transportation (DOT) has completed a pilot project in which data from a statewide network of weigh-in-motion (WIM) sensors were used to assist in scheduling weight-enforcement activities of patrol personnel. The purpose of the project was to determine if one of the division’s objectives—reducing infrastructure damage from overweight vehicles—could be better realized by using WIM data when dispatching officers. Data for the project were obtained from Montana’s state truck activities reporting system (STARS), which consists of WIM sites deployed around the state to collect information for a spectrum of Montana DOT activities. In this case, the STARS data were processed to determine the pavement damage caused by overweight vehicles each month during the baseline year. The trends identified from this analysis were used in the subsequent year to direct patrol efforts each month to the five sites that historically had experienced the greatest pavement damage from overweight vehicles. Officers were directed to the specific vehicle configurations historically responsible for the damage, as well as to their direction of travel and time of operation. During this year of WIM-directed enforcement, pavement damage from overweight vehicles decreased by 4.8 million equivalent single-axle load miles, and the percentage of vehicles operating over weight decreased by 20% across all STARS sites (both enforced and unenforced). While changes in loading patterns were observed during the enforcement activities (fewer overweight and more weight-compliant vehicles), the effectiveness of the focused enforcement in producing long-term changes in loading behaviors was uncertain.