Development of an overweight vehicle permit fee structure for Illinois

Permits are one of the most effective and common tools for state agencies to regulate the operation of overweight and oversize trucks to ensure the safety of passenger and freight traffic and to minimize damage to pavements and bridges. Although the State of Illinois uses a relatively comprehensive permit system, many of its parts have not been revised for more than 30 years. Therefore, the objective of this study was to evaluate up-to-date impacts of overweight (OW) trucks and develop an equitable permit system. In this study, impacts of OW trucks on bridges, pavements, and traffic safety were evaluated; and individual fees were developed for each. The most recent databases on infrastructure condition and state-of-the-art prediction algorithms were employed to produce realistic and up-to-date assessment of OW trucks’ impact. Finally, two approaches were recommended to combine individual fees. The first approach requires developed frameworks for calculating individual fees to be integrated with existing geographic information system-based online permit tools that are currently used by many departments of transportations (DOTs). These tools compute the fee for each vehicle by reporting a route based on user-input origin/destination. The information specific to each OW vehicle (e.g., mile, axle spacing, weight, bridge inventory rating) can be extracted from the reported routes and injected into the developed frameworks. Thereby, the fee can be computed in an equitable and more accurate way. The second approach is converting the frameworks into a formula to conform to the conventional permit fee calculation schemes (e.g., table format).