TRUCK AND BUS REGULATION
California's comprehensive emission standards for diesel vehicles
Understanding the Regulation
The Truck and Bus Regulation is CARB's flagship rule requiring diesel trucks and buses operating in California to meet specific particulate matter (PM) and oxides of nitrogen (NOx) emission standards.
This regulation applies to nearly all diesel-fueled trucks and buses with a gross vehicle weight rating (GVWR) greater than 14,000 pounds, including vehicles registered outside of California that operate within the state.
Key point for Canadian carriers: If your trucks enter California even once, they must comply with these regulations or face penalties.
Who Must Comply?
- 2012-2022 engines: Must have DPF installed
- Pre-2010 engines: Must upgrade or replace
- 2027: Must meet 2010 engine standards
- Similar compliance schedule as heavier trucks
- May qualify for flexibility options
- Small fleet exemptions available
- Transit buses: Strict zero-emission timeline
- School buses: Phased compliance schedule
- Shuttle buses: Same as truck requirements
Compliance Options
Upgrade to a 2010 or newer model year engine that meets current standards.
- Long-term solution
- Best emissions performance
- No future upgrades needed
Install a CARB-verified Diesel Emission Control Strategy (like a DPF).
- Lower upfront cost
- Extends vehicle life
- Verified by CARB
Purchase a new or used vehicle with a compliant engine.
- Modern safety features
- Better fuel efficiency
- Longer service life