CARB: Heavy-Duty In-Use Compliance Program

Scope

This program applies to anyone operating a heavy-duty vehicle in California. However, vehicles and companies are randomly selected to participate, and participation is voluntary.

Regulatory citations

• Title 13, California Code of Regulations, Sections 2111 to 2140

Key definitions

• California Air Resources Board (CARB): The state agency in California charged with controlling air pollution.
• Covered vehicle: A vehicle diesel-powered heavy-duty vehicle operating in the state of California.
• Engine family: An engine family is a unique identifier assigned to a group of engines that are built to the same specification and emissions certification.

Summary of requirements

This program is intended to determine if engine families operating on the roadways in California are meeting the emissions standards they were designed to meet. As an example, if the vehicle has a model year 2020 engine, the emissions testing under this program is done to verify the vehicle is still in compliance with the emissions standards that apply to a MY 2020 engine.

Participation in this program is voluntary. Vehicles and companies are selected at random. If selected, the company is contacted by CARB, and details about the testing process and participation are discussed.

The testing involves inspection of the emissions components on the vehicle (to verify they have not been altered or tampered with), an onboard diagnostic (OBD) data download (to confirm the engine is operating as designed), and fitting the vehicle with a portable emission measurement system (PEMS). The vehicle is then operated on routes used by large freight-carrying trucks. The data from the PEMS is then collected and used to determine if the engine was operating within the appropriate emissions standards. After several vehicles with engines from the same engine family have been tested, CARB will determine if the engine family is meeting the applicable emissions standards.

If a family of engines is found to be non-compliant, CARB will work with the manufacturer to correct the discovered issues. Vehicle owners will then receive a recall notice, so vehicles with that engine family can be repaired (at no cost to the owners) and brought back into compliance.