Research Studies

Caltrans has carried out air quality research since the 1970s. Some of the first mobile-source dispersion models were developed here; Caltrans worked with the Air Resource Board (ARB) developing early versions of EMFAC; key mobile source emission data were collected by Caltrans in collaboration with ARB and others, and Caltrans has worked with various university partners including the University of California, Davis and Riverside.

From the late 1990s until about 2008, Caltrans had an ongoing relationship with the University of California, Davis (UCD) that we called the "Caltrans/UCD Air Quality Project" (UCD usually reversed that: UCD/Caltrans). Since about 2008, air quality research has continued under the auspices of the Caltrans Divisions of Research and Innovation, Environmental Analysis, and Transportation Planning. Caltrans staff members also frequently participate in working groups and research project panels with the American Association of State Highway and Transportation Officials (AASHTO) and the Transportation Research Board (TRB)/National Cooperative Highway Research Program (NCHRP).

This site attempts to make available a central directory of Caltrans-sponsored and partnered air quality research project results. It's organized partially by time period, and also by performing entity or project. It's not by any means exhaustive, but an effort has been made to be reasonably complete. In most cases, products are listed as links to another web site, whether within Caltrans or external; there is no guarantee that such links will remain active.

Please note that most of these documents and data files are historical in nature and may not be directly related to current policies. In addition, by their nature (scanned images of paper documents or raw data files in many cases) they may not fully comply with Section 508 of the U.S. Rehabilitation Act.