California Department of Transportation

PrePass® Weigh Station Bypass


PrePass® is an automated, state-of-the-art system allowing heavy vehicles that are registered in the program to legally bypass open weigh stations.

For questions re. PrePass, call 1-800-PrePass (1-800-773-7277) or go to the PrePass web site at

Transponders: Carriers obtain special transponders used for communication between computers in the weigh stations and the vehicles.
Green Signal: If all requirements for weight, size, safety, etc. are met, the driver receives a green signal that allows the vehicle to bypass the weigh station.
Red Signal: If all requirements for weight, size, safety, etc.are NOT met, the driver receives a red signal which requires the vehicle to go through the weigh station.
Non-PrePass™ vehicles: All heavy vehicles that are not registered in PrePass are required to pass through weigh stations that are open.
Program Statistics: The system has been in operation in California since 1994. Currently, there are 35 weigh stations across California deploying the PrePass™ technology.

How PrePass® Works (.jpg)
This graphic diagram shows the process of the PrePass™ system.

Bypass Sites Map (.pdf)
This 2.2 megabyte map shows the location of the California PrePass™ sites.
Bypass Sites List
This list includes the location and status of all bypass sites in California. 
PrePass How to register for PrePass®
The PrePass™ web site allows you to register easily and learn more about the PrePass™ system.

For questions regarding PrePass®, such as enrollment and account information, call:
1-800-PrePass (1-800-773-7277).

WIM Headquarters Contacts: Email: Phone:
Stan Norikane, Transportation Engineer (916) 654-5651
Linda Savinelli, Transportation Engineer (916) 654-7375
Vicki Dickey, Staff Services Analyst (916) 654-6403