We control diesel exhaust smoke by means of two diesel inspection and maintenance programs, one for fleets of nine or more heavy-duty vehicles and another for smaller fleets and privately owned vehicles.
Large fleets (nine or more vehicles)
- If you own or operate a larger diesel fleet, you must take part in a Diesel Fleet Self-Certification Program, which requires fleet owners and operators to self-inspect and certify their vehicles annually to maintain compliance with state smoke opacity standards.
- Fleets subject to self-inspection and certification are those within the Automobile Inspection and Readjustment Program area with nine or more diesel vehicles of more than 14,000 pounds empty weight.
- New heavy-duty diesel vehicles are exempt from testing for four years.
Individual and small fleets (eight or fewer vehicles)
- If you own a small fleet or a private diesel vehicle, you must take part in the Diesel Opacity Inspection Program.
- This program is for all light-duty diesel vehicles, as well as heavy-duty diesel vehicles not subject to the large-fleet self-certification program.
- New diesel vehicles are exempt from testing for four years.
- The Diesel Opacity Inspection Program requires eligible vehicles (ten model years old or newer) to be inspected every two years. Vehicles that are eleven model years old or older must be inspected annually.
- The program applies only to the Automobile Inspection and Readjustment Program area and uses a loaded-mode dynamometer-based test. All inspections are performed by private, state-licensed diesel inspection stations.