Clean Truck Check (CTC) is California's periodic CARB emissions testing program for many heavy-duty diesel vehicles. If your trucks operate in California, you may need recurring inspections to stay compliant — separate from CTC-VIS certificate filing after you pass.
This guide answers the most common Clean Truck Check questions in plain language. CARB Test Finder is an independent directory — not CARB.gov. Confirm requirements for your fleet on the Clean Truck Check overview.
Who needs a CARB emissions test?
Most heavy-duty diesel vehicles over 14,000 lbs GVWR that operate in California must participate in Clean Truck Check. Whether a specific unit is covered depends on:
- Vehicle weight class and fuel type
- How the vehicle is used (on-road, drayage, port, etc.)
- Registration and reporting status with CARB
Fleet owners should verify obligations for each unit rather than relying on general summaries alone. If you are unsure, start with our Clean Truck Check eligibility checker, then search verified CARB testers near you and confirm vehicle type when you book.
What happens during a Clean Truck Check inspection?
A CARB emissions test under Clean Truck Check typically includes:
- Visual inspection of emissions-related components
- OBD and emissions checks appropriate to the vehicle
- Documentation of results for your records and reporting
Most inspections take about 20 to 45 minutes, depending on the vehicle and testing site. Arrive with registration details and allow extra time for paperwork.
For a full pre-appointment checklist, see our guide on how to prepare for your CARB emissions test.
How often is Clean Truck Check testing required?
Testing frequency depends on your vehicle category and current CARB program rules. Many covered vehicles need testing twice each year; others follow a different periodic schedule tied to compliance reporting.
See the next window with the Clean Truck Check deadline calculator — most fleets test twice a year, and agricultural vehicles and motorhomes often test annually.
Missed deadlines can lead to registration holds, fines, or operational delays. Mark inspection windows on your fleet calendar and book early in busy regions like Los Angeles, the Inland Empire, and the Central Valley.
How much does a CARB emissions test cost?
Clean Truck Check testing fees vary by tester, location, vehicle type, and whether you use a fixed site or mobile CARB testing. That inspection charge is separate from CARB’s 2026 $32.13 annual fee and from optional CTC-VIS filing.
Add the three bills for a ZIP with the Clean Truck Check cost calculator, or read the full breakdown in CARB emissions test cost in California. Compare nearby testing locations by ZIP.
Clean Truck Check vs. CARB certification filing
Testing and CTC-VIS certification filing are related but not the same step:
| Step | What it is |
|---|---|
| CARB emissions test | On-site Clean Truck Check inspection at a qualified location |
| CTC-VIS / CARB certification | Reporting and certificate steps after a successful test |
CARB Test Finder does not issue the official compliance certificate. Need a tester first? Find verified CARB testers by ZIP. Already passed and need filing support? See our guide on CTC-VIS certification after you pass or start Clean Truck Check CARB certification support.
How to find CARB testing locations near you
Use CARB Test Finder to search California CARB testing locations by ZIP code. Compare:
- Vehicle types served
- Mobile vs. fixed-site testing
- Services listed on each tester profile
Next steps for fleet owners
- Confirm whether your vehicles fall under Clean Truck Check with the eligibility checker
- Gather registration and vehicle details before booking
- Search nearby testers and schedule a CARB emissions test
- Plan CTC-VIS filing support if you need help after passing
Ready to search? Find a CARB tester near you.
