Down and dirty facts about the CARB Clean Truck Check program.

What is CARB and what’s the new program?

“CARB” stands for California Air Resources Board.

According to the agency’s website, its Clean Truck Check Regulation (CTC) program is a “comprehensive heavy-duty vehicle inspection and maintenance (HD I/M) regulation to ensure that vehicles’ emissions control systems are properly functioning when traveling on California’s roadways.”

Under these rules, periodic vehicle testing is combined with emissions monitoring and enforcement to identify vehicles that need emissions-related repairs. And to ensure that the carriers, fleets and drivers responsible for those vehicles have those repairs performed as soon as possible.

Why is CARB implementing the CTC program?

Combustion-powered commercial vehicles emit multiple air pollutants, including particulate matter, oxides of nitrogen and greenhouse gases, that impact people’s health. This program is designed to reduce the amount of toxic air pollution produced by commercial vehicles that travel through California—regardless of their industry or where they’re based.

While California has made significant strides in reducing air pollution, this additional measure is required to further reduce the harmful emissions its communities breathe and help the state meet ambient air quality standards and climate goals.

When does Clean Truck Check enforcement start?

Deadlines vary for each vehicle throughout the year depending on the vehicle’s registration or VIN. Enforcement of the CTC began in January 2025.

“All compliance deadlines on or after January 1, 2025 will require the submission of a passing emissions compliance test as part of the vehicle’s compliance demonstration. Emissions compliance testing must be performed by a CARB credentialed tester and passing tests may be submitted by the tester up to 90 days prior to the vehicle’s compliance deadline to allow time for any necessary repairs.” – CARB Overview Fact Sheet for its Clean Truck Check

Sound complicated? It can be, especially for larger fleets that have to coordinate testing and logistics. However, we won’t leave you to go alone. Zonar Emissions Check™ makes compliance easier and more cost effective. And eliminates downtime associated with pulling vehicles for testing. More on that in a moment; keep reading.

Which vehicles fall under CARB’s Clean Truck Check program?

Clean Truck Check requires almost all non-gasoline trucks, buses, public vehicles (federal, state, and local government), motor coaches, transit buses, shuttle buses, school buses, hybrid vehicles, commercial vehicles, personal vehicles, California-registered motorhomes, single-vehicle fleets, and vehicles registered outside of California (excluding motorhomes) with a gross vehicle weight rating (GVWR) over 14,000 lbs. that operate in California on public roads and highways to report, pay annual compliance fees, and undergo emissions compliance testing to comply with Clean Truck Check.

Regardless of where the vehicle is based, if fits the above description and travels on California’s public roads and highways, that vehicle falls under the program. So if you have a commercial truck (for example) based out of New Mexico, having an continuously connected device to remotely meet the CTC requirements means not having to interrupt its long-haul trip with downtime for testing.

How do I ensure my fleet and drivers comply?

1. Maintain your fleet’s heavy-duty vehicles to ensure their emissions controls stay in proper working condition. If you, your drivers or your maintenance technicians discover an issue with a vehicle’s emissions controls, address and repair it—quickly.
2. Make sure drivers can easily access proof of successful testing during roadside inspections.
3. If a vehicle’s test results indicate it might be emitting higher than the acceptable range, CARB may send you a notice. Submit a passing test to CARB within 30 days of that notice.
4. Continue annual inspections for vehicles subject to the Periodic Smoke Inspection Program (PSIP).

In addition to all of the above, work with a provider (like us) who developed a remote solution that helps you comply without downtime. A provider who keeps up with the latest regulations so we can help you comply. And who picks up the phone when you call with questions.

Zonar can help your fleet comply.

Zonar is the first to receive an executive order for telematics devices that CARB call a continuously connected remote OBD (CC-ROBD). Which means we are first to support California fleets with CARB-validated testing and easily available results. Unlike some other providers, we’re here to help you succeed and to make sure our tech delivers on its promise.

Questions? Contact us, we’re here with answers.