On July 26, 2007, the State of California’s Air Resources Board adopted a regulation to reduce diesel particulate matter (PM) and oxides of nitrogen (NOx) emissions from in-use (existing) off-road heavy-duty diesel vehicles. The regulation applies to self-propelled diesel-fueled vehicles that cannot be registered and licensed to drive on-road. Examples include loaders, crawler tractors, skid steers, backhoes, forklifts, and airport ground support equipment. Vehicles with engines less than 25 horsepower are exempt.

The regulation also includes the Surplus Off-road Opt-in for NOx (SOON) program. Local air districts may opt into the SOON program to reduce NOx emissions beyond what is required by the regulation. If our District chooses to participate, we would make incentive money available for fleets that operate in our district to take additional actions to reduce NOx emissions.

Fleet Survey

In order to evaluate the potential benefits of the SOON program, the District needs your help in determining the number of affected vehicles operating in the Valley. You can help us do this by downloading and completing a survey and mailing (or e-mailing) it back to the District.

Survey Forms
		Off-Road Diesel Equipment Survey Forms

ARB Tools and Fact Sheets

• California Air Resources Board has developed several fact sheets for their In-Use Off-Road Diesel Vehicle Rule. To visit their site and view these fact sheets, click here.
• Fleet Average Calculators. California Air Resources Board has developed fleet average calculators that allow fleets to experiment with different turnover, repower, and retrofit strategies to understand what the in-use off-road diesel vehicle regulation will require. There is one calculator for large / medium fleets and one for small fleets. Small fleets are municipalities and small businesses with less than or equal to 1,500 horsepower total of affected vehicles. To visit their site and download these calculators, click here.