Which organization sets emissions standards that smog checks must comply with?

The California Air Resources Board (CARB) is responsible for setting and enforcing air quality standards and emissions regulations in California. In the context of smog checks, CARB establishes the emissions limits that vehicles must meet to ensure they do not contribute excessively to air pollution. These standards are critical for maintaining air quality and protecting public health, which is why compliance with CARB regulations during smog checks is mandatory for vehicles registered in California.

While the Environmental Protection Agency (EPA) does set national emissions standards, CARB has more stringent requirements specifically tailored for California's unique air quality issues. The National Highway Traffic Safety Administration (NHTSA) primarily focuses on vehicle safety and fuel economy and does not deal directly with emissions standards. The Department of Motor Vehicles (DMV) plays a role in vehicle registration and compliance but does not set emissions standards. Therefore, CARB is the correct organization associated with setting the emissions standards for smog checks.