California Air Resources Board

Principal Investigator/Authors: Mary Leonard

Contractor: South Coast Air Quality Management District

Contract Number: 16RD012

Project Status: Completed

Relevant CARB Programs: Mobile Source Emissions Research Program, Innovative Clean Transit, Low Carbon Fuel Standard, Research Program

Topic Areas: Heavy-Duty Vehicles, Air Pollution,  Advanced Technology & Low Carbon Transit, Tracking Emissions

Research Summary:

Current heavy-duty engine emission standards have reduced both oxides of nitrogen (NOX) and particulate matter (PM) emissions significantly in the South Coast Air Basin (SoCAB). However, it is projected that heavy-duty vehicles (HDV) will still be a dominant source of those emissions in the SoCAB, and there is a need for additional reduction in NOX emissions to meet National Ambient Air Quality Standards (NAAQS) for ambient PM and Ozone. Understanding the impact of conventional and alternative engine and fuel technologies on in-use emissions and fuel use is critical for developing State Implementation Plans (SIPs) as well as for understanding the effectiveness of potential rules to further lower emission standards for HDVs.

The South Coast Air Quality Management District (AQMD), California Energy Commission (CEC), Southern California Gas Company (SoCal Gas), and California Air Resources Board (ARB or Board) jointly developed a research plan for collecting in-use vehicle activity, emissions, and fuel use data from up to 200 HDVs in various vocation types including goods movement, transit bus, school bus, refuse, and local delivery and for developing effective strategies to achieve the NAAQS requirements in the region. ARB will participate in this project as a co-funding organization.

Our current research investigations characterizing HDV activity profiles by vocation and quantifying the potential greenhouse gas (GHG) benefits of aerodynamic features on HDV use only onboard diagnostic (OBD) data, and do not include measurements of in-use emissions and fuel use, due in part to limited resources. We will use the findings from this research work to expand our understanding of vocational use of HDVs and to develop effective strategies for achieving the federal ambient air quality standards and the state GHG reduction goals.

Keywords: heavy-duty vehicles (HDV), NOx, particulate matter, PM, emissions, South Coast Air Basin (SoCAB), NAAQS, ozone, alternative engine, alternative fuel, State Implementation Plan (SIP), lower emissions, in-use activity