A Synthesis of Overweight Truck Permitting

For purposes of safety and system preservation, trucking operational characteristics are regulated through legislation and policies. However, special permits are granted for trucks to exceed specified operational restrictions. Thus, the Indiana DOT not only seeks highway operations policies that retain/attract heavy industry including those that haul large loads but also seeks to protect the billions of taxpayer dollars invested in highway infrastructure. As such, it is sought to avoid policies that may lead to premature and accelerated deterioration of assets through excess loading or undue safety hazard through oversize loads. This study was carried out primarily to document the state of practice of truck weight permitting in Indiana vis-a-vis those of its neighboring states. This was done on the basis of the fee amounts, fee structure, and the ease of the permit acquisition process for the permit applicant. The study determined that while the upper thresholds (dimensions and weights) for legal trucking operations are generally the same across states, those for extra-legal operations vary considerably. Also, findings from published literature, agency websites, and phone interviews showed that there is great variability in overweight and oversize truck permitting criteria across the states. Furthermore, it was seen that no state has adopted explicitly the weight-distance concept for its overweight trucks. However, in the states of Indiana, Ohio, and Illinois, the fee structures for overweight vehicles include weight levels and extents of travel, and thus operate in a manner similar to a weight-distance fee. From the perspective of overweight and oversize thresholds and associated permit fees, it was observed that a number of states such as Indiana appear to be generally more favorable to trucking because they have relatively higher upper thresholds for defining an overweight truck and/or relatively lower fees for overweight trucking operations. However, as demonstrated in the excel spreadsheet case studies that accompany this report, the differences in fees incurred by truckers across the states are significantly influenced by a variety of factors including the trip circumstances, permitting criteria, and trip frequency and distance. This report also documents the streams of revenue from the permits issued for extra-legal trucking operations over the recent past: approximately $12 million annually. On the subject of revenue neutrality, the study reports that highway agencies that had switched from a single-trip permit system to an annual flat fee permit system report that they benefited from cost savings due to reduced monitoring efforts of truck trips but had lost significant revenue overall. Using data from a national study, the report quantifies the extent to which each additional payload increases pavement deterioration. The data also suggests that having more axles on a truck reduces pavement deterioration and consequently, damage repair cost, but could decrease the revenue to be derived from overweight permitting. In conclusion, the study recommended the conduction of a cost allocation study to update these load-damage relationships as well as the overweight permit fee structures, to reflect current conditions in Indiana.