PrePass is an intelligent transportation system (ITS) that electronically verifies the safety, credentials, and weight of commercial vehicles as they approach participating state highway weigh stations.
[1] In 1993 the non-profit Heavy-Vehicle Electronic License Plate, Inc. (HELP) was formed by several state transportation directors and trucking company executives and Lockheed Martin was contracted to develop a system.
By 1998 PrePass was in use in 35 weigh stations in Arkansas, Arizona, California, Colorado, Mississippi, Montana, Nevada, New Mexico, Texas, and Wyoming.
[2] The only equipment required for a truck to participate in PrePass is a vehicle-specific transponder, mounted on the interior windshield with double-sided tape or dual-lock strips.
Weigh-in-Motion (WIM) technology is also used at many locations to verify the truck’s configuration and ensure its axle and gross vehicle weight are within acceptable limits.
As the truck passes beneath another electronic “reader” nearer the inspection point, the in-cab transponder receives a signal indicating whether the vehicle is authorized to bypass.