Clean Truck Check Credentialed Tester

Clean Truck Check Testers in California

2,570 CARB-credentialed testers across 513 cities in six freight-corridor regions.

Recommended testers

By region

Top cities

453 more cities — see each region for the full list.

Trucking activity in California

FMCSA MCMIS reports 132,700 active motor carriers registered with operations in California. The Clean Truck Check program reaches the heavy-duty subset that operates in California, which is why this directory exists.

Interstate carriers
104,100
Intrastate carriers
28,600
Hazmat carriers
7,100
Passenger carriers
2,820
Heavy-duty power units
376,500
Medium-duty power units
52,400

Source: FMCSA MCMIS Registration Statistics. Snapshot 2024-10-01. Last fetched 2026-05-18.

CARB Clean Truck Check program status

The California Air Resources Board administers Clean Truck Check as the statewide heavy-duty inspection & maintenance program. Non-gasoline vehicles over 14,000 lb GVWR operating in California must comply, regardless of where the vehicle is registered. Only out-of-state registered motorhomes and some special-purpose government vehicles are exempt.

2025 – 2027
2× per year

Two passing Clean Truck Check tests per vehicle per year, plus the annual fee paid through CTC-VIS.

2028 onward
4× per year

Quarterly cadence kicks in starting October 2027 for compliance deadlines falling in January 2028 and later — four passing Clean Truck Check tests per truck per year.

Find your next test deadline →

Compliance is filed through CTC-VIS — CARB's vehicle-inspection portal. Tests are performed by CARB-credentialed testers listed on this directory.

Compliance reference →2027 testing changes →CTC-VIS account setup →

Source: CARB Clean Truck Check program page. Cadence dates from CARB rulemaking (Title 17 CCR §§ 2196 et seq.). Rule snapshot 2026-01.