PrePass lets trucks bypass scales if they meet safety and paperwork requirements. An antenna on the highway about a mile before the weigh station reads a small transponder on the truck's windshield. If the carrier and truck have the proper credentials, the transponder flashes a green light indicating the truck doesn't have to pull in. A red light means the trucker has to pull into the weigh station. There are more than 60 PrePass sites currently operational throughout the country; by the end of the year, that number is scheduled to rise to nearly 100.
Landstar distributed a PrePass kit for each of the 8,500 trucks in the Landstar system, making it the nation's largest PrePass carrier.