This page last reviewed on November 19, 2008
This page contains instructions and emission calculators for Urban Bus and Transit Fleet Vehicle PM and NOx requirements. These calculators are provided for Transit Agencies' convenience to determine emission reductions`.
matter (PM) and oxides of nitrogen (NOx) calculations are based on the
engine emission standards set forth in title 13, California Code of
Regulations (CCR) section 1956.1 (urban bus engine
standards) and 1956.8 (heavy-duty engine
standards). Emission standards are listed below. Some engines may be
certified to a lower optional standard for NOx. Typically, those are
alternative-fuel engines. Check your engine's certification
Executive Order or contact your dealer to get more information on
your engine's emissions standard.
ARB has developed calculators to assist in determining your fleet's compliance. The calculators are set up to meet most fleets' needs, but if your engine criterion is not listed on the calculators, please contact ARB staff for assistance.
Using the calculator:
Separate your fleet into urban buses and transit fleet vehicles.
|Nominal expected NOx level based on emission standards of 2.4 g/bhp-hr NOx plus non-methane hydrocarbons (NMHC) or 2.5 g/bhp-hr NOx plus NMHC with 0.5 g/bhp-hr NMHC cap to take effect in October 2002 for those engines subject to the Settlement Agreements between the heavy-duty engine manufacturers, the United States Environmental Protection Agency (U.S. EPA), and ARB. As part of the Settlement Agreements, the federal heavy-duty engine emission standards adopted for 2004 took effect in October 2002.|
|Seven engine manufacturers (Caterpillar, Cummins, Detroit Diesel, Mack, Navistar, Renault and Volvo) were required to "pull ahead" and meet the 2004 NOx emission standard by October 2002.|
|Between 2007 and 2009, U.S. EPA requires 50 percent of heavy duty diesel engine family certifications to meet the 0.2 g/bhp-hr NOx standard. Averaging is allowed, and it is expected that most engines will conform to the fleet NOx average of approximately 1.2 g/bhp-hr.|