2013 or newer diesel engines

2018 or newer alternative fuel engines

• Heavy-Duty Trucks: GVWR over 14,000 lbs

• Bus Fleets: All public and private buses, including school and transit buses.

• Vocational Vehicles: Trucks used for construction, delivery, and specialized tasks.

• Light-Duty Trucks: Some light-duty vehicles may need inspections based on weight.

• Transport Refrigeration Units: Vehicles with refrigeration systems for perishable goods transport.

• Hazardous Material Transporters: Vehicles for transporting hazardous materials.

• Heavy-Duty Vehicles: Heavy-duty vehicles used to imported goods from other states.

• Fleet Operations: Companies with multiple vehicles.

  Testing Frequency

• OBD-equipped vehicles: 2 times per year, increasing to 4 times per year after 3 years

• Non-OBD equipped vehicles: 2 times per year. Diesel vehicles require smoke opacity test and a visual inspection. Alternative fuel vehicles only required to complete the visual inspection.

• Agricultural vehicles and California registered motorhomes: Once per year.

  Which vehicles are not subject to the regulation?

The heavy-duty vehicle types shown below are not subject to the regulation:

• Zero-emission vehicles

• Military tactical vehicles (title 13, CCR, section 1905)

• Emergency vehicles (California Vehicle Code section 165 or California Health and Safety Code section 1797.84)

• Historical vehicles (authorized by California Vehicle Code section 5004)

• New vehicles with engines certified to the most stringent optional, NOx standard (less than or equal to 0.01 g/bhp-hr) -Only during the first four years of Clean Truck Check implementation (2023-2027)

• Motorhomes registered outside of California

• Vehicles operating under an experimental permit (authorized by California Health and Safety Code section 43014