Using weigh-in-motion data to calibrate trade-derived estimates of mexican trade truck volumes in texas

Weigh-in-motion (WIM) sites are being installed along many highway corridors that carry international trade trucks. Estimating the numbers of trucks carrying international commodities currently relies on manipulating and adjusting trade databases. The variety of vehicle classification data measured at WIM sites provides a rich source of data with which to enhance this adjustment process. Previous WIM border data have focused on port-of-entry truck traffic axle loads, which are heavily influenced by drayage operations. Examined is how WIM data collected at ports of entry and on truck corridors can be used in the determination of standardized truck volumes (termed equivalent trade trucks or ETT) on international highway corridors. Data from the Texas-Mexico border are used to determine ETT North American Free Trade Agreement volumes.