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Trucks enrolled in PrePass are assigned small, wireless transponders that easily mount onto the vehicles’ windshields. As one of these trucks approaches a PrePass-equipped weigh station, an electronic reader on a boom over the road automatically scans the transponder and identifies the vehicle. |
A secure PrePass computer located inside the scale house accesses the vehicle information associated with the transponder, and validates it to ensure compliance with state requirements. At the same time, technologies such as weigh in motion (WIM) scales are often used to verify the truck’s configuration and ensure axle and gross vehicle weights are within acceptable limits.
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Finally, as the truck passes beneath a second boom, a signal indicating whether the vehicle may bypass is transmitted back to the transponder. If the vehicle’s information cannot be validated, or if it is selected for a random manual inspection, a red light on the transponder alerts the driver to stop. If the vehicle’s credentials, safety, and weight are all in order however, a green light tells the driver to go ahead and bypass the facility. |