Clean Truck Check explained: reporting, the compliance fee and emissions testing

What Clean Truck Check is

Clean Truck Check is the common name for CARB's Heavy-Duty Inspection and Maintenance (HD I/M) program. It replaced the older periodic smoke inspection program and moved emissions compliance from a roadside spot check to a continuous, reported obligation tied to each vehicle.

CARB states that the program requirements are in effect for subject vehicles, including vehicles registered outside California when they operate in the state, to report, pay an annual compliance fee, and submit required passing compliance tests.

Which vehicles are subject to it

There are exemptions and special categories in the regulation. Check your specific vehicle class against CARB's own applicability guidance before assuming a unit is out of scope.

• Non-gasoline heavy-duty vehicles operating in California above the program's weight threshold, including trucks, tractors and buses
• Vehicles registered outside California that operate in the state
• Both company-owned and owner-operator units — applicability follows the vehicle, not the size of the fleet

The three obligations

• Reporting: each subject vehicle is reported in CARB's Clean Truck Check vehicle information system.
• Compliance fee: an annual per-vehicle compliance fee. CARB adjusts the fee amount by rulemaking, so confirm the current figure on CARB's fee page rather than relying on a number you were quoted last year.
• Emissions compliance testing: passing tests submitted on the schedule that applies to the vehicle. CARB's testing requirements took effect on October 1, 2024, and compliance deadlines of January 1, 2025 or later require a passing compliance test as part of the compliance demonstration.

How often testing is required

Testing frequency depends on the vehicle. CARB publishes separate requirements for vehicles subject to semi-annual compliance, and different handling for OBD-equipped versus non-OBD vehicles. Confirm your unit's category in CARB's guidance — the interval is a property of the vehicle, not a single sitewide rule.

Practically, this means the compliance calendar for a mixed fleet is per-unit. That is the point at which spreadsheets usually fail: a missed test surfaces as a registration hold, not as a reminder.

What happens if you miss it

• DMV registration can be blocked for vehicles that are not compliant
• Enforcement can occur when the vehicle operates in California, including for out-of-state units
• Penalties accrue per vehicle, so a small fleet can carry a large exposure quietly

The records to keep on each unit

AssetStacc tracks Clean Truck Check alongside carrier 90-day and federal annual deadlines on the asset record, so the compliance date, the test evidence and any repair that followed live on the same unit rather than in three separate inboxes.

• Confirmation that the vehicle is reported, with its identifiers matching registration
• Proof of annual compliance fee payment for each compliance year
• Each passing compliance test result and its date
• Repairs performed to resolve a failed test, with the retest that cleared it