Log In

Injury Collisions in Los Angeles County (SWITRS) 2003-2012

The Statewide Integrated Traffic Records System (SWITRS) is collected and maintained by the California Highway Patrol (CHP).  SWITRS contains all collisions that were reported to CHP from local and governmental agencies.

The data available here were downloaded from the Transportation Injury Mapping System (TIMS) as UC Berkeley (http://tims.berkeley.edu/index.php).  TIMS was established by researchers at the Safe Transportation Research and Education Center (SafeTREC) at the University of California, Berkeley to provide data and mapping analysis tools and information for traffic safety related research, policy and planning.

The TIMS site contains a very good resources page with lots of information about SWITRS as well as data downloads, mapping applications, and codebooks.  Click here to go to the site.

Processing for LA County

switrs_joinsData downloaded from the TIMS site contains three tables (see figure to left):

  1. CRASH table which contains crash information (and XY coordinates) – unique CASEID field
  2. PARTY table which contains information about the parties involved – unique VEH_ID field (see below)
  3. VICTIM table which contains information about injured parties  – unique VEH_ID field (see below)

I initially selected only those records from the CRASH table where COUNTY = ‘LOS ANGELES’

The TIMS site notes: CASID and PARNUM uniquely identify vehicles in the database.  The 2 variables have been appended as VEH_ID (CASID & PARNUM) because it is easier to join with a single identifying variable.

I have created two resulting datasets, a PARTIES dataset and a VICTIM dataset, a recommended by TIMS.

A common way to work with data of this structure is to create a party-level table or a victim-level table that has data from all its parents joined to each row.  For example, if you plan to do analyses at the victim-level, you can start with a VICTIM table and join in values from corresponding PARTY and CRASH tables.  In the figure, the crash variables and the party variables are joined to the victim table.  Doing so provides a victim-level table that can be summarized (for example, count or sums can be generated), while considering PARTY or CRASH variables.  You must keep in mind that the party and crash variable will repeat for as many victims as there are.

Data Download

Download either of the following shapefiles


The SWITRS Codebook with all of the relevant codes is available in the following links:

Or print it here: TIMS – Transportation Injury Mapping System – SWITRS Codebook

Using GIS Data on this site

GIS Data downloaded from this site generally requires GIS software to view. Click here for a list of GIS Data Viewers

GIS data available on this website is provided AS IS - please read the GIS Data Portal Terms of Use

Data Field Descriptions

See the code book reference above

GIS Source Information
Database Name: eGIS_Transportation
Feature Class Name: CHP_SWITRS_VICTIMORPARTY_2003_TO_20012
Feature Dataset Name (if applicable):
Reference Date: 2012
Accuracy: Other
Update Frequency: Annually
Access Constraints:None

Contact Information

Leave a Reply