California Weigh Stations: When to Pull In or Bypass

Approaching an open California weigh station with a green light on your in-cab device can leave you unsure whether to pull in. An open station can authorize some trucks to bypass and stay on the mainline. Identify the instruction issued to your truck on this approach and check that your equipment and load qualify.

Prepare to enter an open station

Under California Vehicle Code § 2813, when the California Highway Patrol (CHP) is conducting commercial vehicle inspections and a sign directs drivers to stop, they must stop for inspection. Inspectors may check equipment, loading and driver qualifications as well as weight. An empty truck or a recent commercial scale ticket does not by itself excuse entry.

Eligible vehicles enrolled in PrePass or Drivewyze PreClear can receive a bypass instruction. The California Department of Transportation (Caltrans) describes these services in its weigh station bypass information. A bypass authorizes the truck to remain on the mainline past the station. It does not mean diverting onto local roads to evade inspection. Without enrollment or a valid instruction for this approach, follow the OPEN sign and on-site instructions to enter.

Read the instruction, not just the alert

Before departure, verify that the service works and the correct vehicle is registered. As you approach, leave room to change lanes safely. Troubleshoot a device while parked. Do not look down to restart an app near the entrance. Common messages have different meanings.

PrePass green light. Under the PrePass FAQ, green authorizes a bypass subject to restrictions such as those on the load. A red light or no signal means pull into an open station. Silence is not clearance.

“Bypass Granted” is a Drivewyze bypass instruction, subject to the applicable restrictions. A heads-up notification only warns that a station is ahead. It does not yet give a bypass decision.

“Pull in unless closed” directs you into an open station. Caltrans explains that you may stay on the mainline if the station is marked CLOSED. You must still obey a separate lawful direction from an officer.

“Follow Road Signs” means look to the posted signs for the instruction. The message itself does not grant a bypass.

“Follow Transponder” means read the actual signal from the in-cab transponder and apply that device’s instructions. The Drivewyze guide for multiple devices can help the carrier confirm how the app and transponder are configured to work together.

If two systems disagree, check both instructions

If you use two bypass services at a site that supports both, pull into the open station if either system directs you to enter. The Drivewyze bypass restrictions make this explicit. PrePass’s California restrictions also require entry if either system gives no signal, even if the other grants a bypass.

Set up the equipment before departure and explain the messages to drivers. If the two systems give conflicting instructions on the road, ask the service provider to investigate afterward so the same issue does not recur on the next trip.

Account for oversize loads and an officer’s directions

The California entry on the PrePass bypass restrictions download page requires oversize or overweight vehicles and loads, including permitted loads, to pull in. Drivewyze also requires oversize, overweight or permitted loads to enter unless its rules expressly provide an applicable exception. For these loads, check the service restrictions before departure.

Even with a green light, you must stop if a uniformed officer lawfully enforcing the Vehicle Code directs your vehicle to stop for inspection. See California Vehicle Code § 2800.

If a road sign and a device seem to conflict, read the actual wording of the sign. Color alone is not enough. If you cannot confirm that this truck may bypass, enter while it is safe to do so. Follow the on-site arrangements if the entrance is closed or an officer directs you otherwise.

If you miss the entrance, stop somewhere safe before following up

The Drivewyze online guide advises drivers to be ready to enter safely. Do not wait so long for an alert that there is no longer room to change lanes. If you miss an entrance you should have taken, do not stop abruptly or reverse on the mainline, cut across lanes or cross a gore area to get in.

Once safely parked, promptly tell dispatch the station, direction of travel, time, signs and device signals you saw. Save the unit number and any available system event log for follow-up. Drivewyze users can consult the Drivewyze mobile guide for past alerts. The actual interface depends on the version in use.

Ask the service provider to check equipment problems and retain the support ticket. If you missed a required stop, contact the relevant enforcement agency, explain what happened and ask how to proceed.

Records can help reconstruct the event but do not guarantee relief from liability. Comply if an officer directs you to stop. Gather evidence and make calls only when safe. A screenshot is not worth creating another hazard while driving.

Disclaimer. This article draws on the California Vehicle Code and Caltrans materials, with PrePass and Drivewyze instructions and restrictions checked against pages available on September 29, 2026. Provider materials explain their own systems and are not government regulations. The article provides general information, not legal advice, individual bypass authorization or a guarantee against liability. Station arrangements, device configurations and service rules may change. Follow applicable law, lawful on-site directions and current provider requirements. Assess any incident using the vehicle, load and records from that approach. Consult a qualified attorney or the responsible agency about a citation or dispute. The author and publisher accept no liability for losses from misuse or application outside the actual circumstances.

California Department of Transportation. “Weigh Station Bypass.” Accessed 29 Sept. 2026.

California Legislature. “Vehicle Code, Section 2800.” Accessed 29 Sept. 2026.

California Legislature. “Vehicle Code, Section 2813.” Accessed 29 Sept. 2026.

Drivewyze. “Drivewyze Bypass Restrictions by State.” 20 May 2025. Accessed 29 Sept. 2026.

Drivewyze. “Drivewyze Mobile Reference Guide.” 10 Jan. 2025. Accessed 29 Sept. 2026.

Drivewyze. “Multiple Transponders Best Practice Guide.” 15 May 2024. Accessed 29 Sept. 2026.

Drivewyze. “Online User Guide.” Accessed 29 Sept. 2026.

PrePass Safety Alliance. “Important Information for PrePass Bypass Customers: Bypass Restrictions by State.” Aug. 2026. Accessed 29 Sept. 2026.

PrePass. “How Does PrePass Work?.” Accessed 29 Sept. 2026.

PrePass. “Weigh Station Bypass Restrictions by State.” Accessed 29 Sept. 2026.