BlogClean Truck Check

Compliance, explained

Guides and updates on CARB Clean Truck Check compliance: testing deadlines, OBD and opacity procedures, out-of-state rules, and what changes next.

Heavy-duty semi truck parked at a California truck stop

ComplianceDeadlines

Clean Truck Check deadlines: what every carrier needs to know

Semi-annual testing, compliance dates and the DMV hold that catches fleets off guard — a plain-English timeline of what CARB expects and when.

July 31, 20262 min read

Diesel tractor unit on a highway in California

TestingOBD

OBD or opacity: which emissions test does your truck need?

One test reads your engine computer, the other measures smoke. Which one applies comes down to a single question about your vehicle — and it changes what you schedule.

July 24, 20262 min read

Freight truck crossing into California on an interstate highway

Out-of-stateCompliance

Out-of-state carriers: when California compliance applies to you

You do not need California plates to fall under Clean Truck Check. If your vehicles operate in the state, the program reaches them — here is the threshold and the fastest way to clear it.

July 17, 20261 min read