The publications and reports on this site that are labeled .pdf (portable document format) require Adobe Acrobat Reader to view them. The software can be downloaded free from Adobe's web site (one-time setup).
Welcome to the Traffic Data Branch
The Traffic Data Branch is responsible for the collection and dissemination of historical volumes (counts). We also produce the Mobility Performance Reports.
TRAFFIC COUNTS, also called Traffic Volumes, are available in various formats, and are only for the State Highway System.
Highways are signed as Interstate, California State Route, or United States Route. See examples below.
Traffic count information for city and county streets may be found at the following links. Click HERE for city traffic volume information. County traffic volume information is available at the County Public Works Department, or the Community Development Office in the area where the street is located.
Explanatory Diagram of Traffic Counts (.pdf)
Caltrans traffic counts are summarized annually into three categories. Necessary software to download .pdf files can be obtained for free by clicking on the desired link in the grey column on the right side of this page:
1. Traffic Volumes (Annual Average Daily Traffic (AADT)) for all vehicles on California State Highways: 2011, 2012
For PDF format, click on the following: 2011 Traffic Volumes Book, 2012 Traffic Volumes Book
This data is also available in Excel format. 2011AADT, 2012AADT
2. Truck Traffic (Annual Average Daily Truck Traffic on California State Highways).
For PDF format, click on the following: 2010 pdf, 2011 pdf, 2012 pdf
The 2011 Truck report is also available in Word format: 2011Truckdoc, 2012Trucdoc
Truck traffic data is also available in Excel format: 2010Truck, 2011Truck, 2012Truck
3. Ramp Volumes on California State Freeways. For downloadable PDF files (organized by Caltrans Districts 1 through 12), click on the following link: 2012
4. Peak Hour Volume Data consists of hourly volume relationships and traffic monitoring sites on the State Highway System.
Morning (AM) and evening (PM) peak periods are expressed as a percentage of Annual Average Daily Traffic (AADT).
Peak Hour reports are available in PDF format: 2008, 2009, 2010, 2011, 2012
For questions regarding AADT reports, Ramp Volumes, or the Peak Hour Volume Data Reports above, please contact: Cindy.Pribyl@dot.ca.gov, or (916) 654-4578.
For questions regarding Truck AADT, please contact: Binoy.Alexander@dot.ca.gov, or (916) 654-6939.
Traffic Volumes and Truck AADT are also available for a nominal fee in hard copy format from Caltrans Publications office at (916) 263-0822. To order on-line, or by mail or fax, go to http://caltrans-opac.ca.gov/publicat.htm.
The Traffic Data Branch produces a monthly Vehicle Miles of Travel (VMT) report (often called the "Trend" report). This report estimates the number of vehicle miles that motorists traveled on California State Highways using a sampling of up to 20 traffic monitoring sites. Various roadway types are used to calculate VMT.
Historical Monthly VMT(.pdf) - Lists monthly/annual statewide Vehicle Miles Traveled (VMT) on State Highways for the past 40 years. 1972-2012.
For information regarding the monthly trend reports, please contact: firstname.lastname@example.org
The Traffic Data Branch also compiles Mobility Performance Reports (MPRs). Caltrans began preparing the annual Mobility Performance Report (MPR) in 2009 as a new type of congestion report using data collected from every day of the year. This report replaces the Highway Congestion Monitoring Program (HICOMP) Report and represents the completion of a transition to an improved way of measuring congestion.
For information regarding MPRs, please contact: Drucilla.Dunton@dot.ca.gov, or at http://www.dot.ca.gov/hq/traffops/sysmgtpl/MPR/index.htm
For more information regarding the WIM system or a map of California's WIM locations visit: http://www.dot.ca.gov/hq/traffops/trucks/datawim
FOR ADDITIONAL INFORMATION NOT FOUND HERE,
PLEASE CONTACT THE TRAFFIC DATA BRANCH MANAGER:
* For travel reports, surveys, and forecast documents, especially related to fuel consumption, Commercial Truck VMT, and VMT data per capita,
please contact another area of Caltrans: