On February 19, 2009, California legislators ended a three-month-long stalemate and passed a budget designed to meet the $41 billion budget shortfall through 2010. A major provision in the bill package adopted as part of the proposed budget would delay the retrofitting of heavy diesel equipment, which would save the construction industry millions of dollars but hurt efforts to reduce harmful emissions.


In July of 2007, the California Air Resources Board (ARB) passed regulations intended to reduce emissions of particulate matter (PM) and nitrous oxide (NOx) from off‑road diesel engines. These regulations require businesses to retrofit or "turn over" their fleets over time. This was the first statewide rule in the nation to require companies to retrofit existing heavy equipment to reduce these toxic pollutants. Please visit the following links for information regarding the original regulations: ARB Off-Road Diesel Vehicle Regulation, CARB New Diesel Emission Regulations Proposal, Update to CARB New Diesel Emission Regulations Proposal.

The California Legislature has directed the ARB to make several changes to the in-use off‑road diesel vehicle regulation. The changes will relax the requirements of the regulation for many large fleets in the early years of the regulation and include the following:

  • For the total cumulative turnover and retrofit requirements for the years 2011 through 2013, fleets may complete 20 percent of the total turnover and retrofitting by March 1, 2011, an additional 20 percent by March 1, 2012, and the balance by March 1, 2013.
  • Fleets using their off‑road vehicles less than they did as of July 1, 2007 may now take credit for this reduced fleet activity to satisfy turnover and retrofitting requirements in 2010 and 2011.
  • Fleets will now be given credit, both PM and NOx, for any vehicle retirements made between March 1, 2006 and March 1, 2010 as long as total fleet horsepower decreased from the previous year.

Although the above changes have been made, the reporting deadlines for the off‑road regulation remain unchanged as follows:  April 1, 2009 for large fleets, June 1, 2009 for medium fleets, and August 1, 2009 for small fleets.

ARB staff will hold a workshop to discuss implementing these changes and ways of mitigating the loss in emission benefits caused by these changes sometime in March.  A public notice with details regarding this workshop will be released soon.

Authored By:

Kyndra Joy Casper

(213) 617-4157


Kyndra Casper is an associate in the Real Estate, Land Use and Environmental Practice Group in the firm’s Los Angeles office.