PROBLEM IDENTIFICATION
As in most urban areas nationwide, the City of Hemet, California has experienced a steady increase in traffic during recent years, resulting in higher levels of congestion and corresponding increases in traffic crashes. California's Statewide Integrated Traffic Records System (SWITRS) provides general crash data by primary collision factor and victim severity. Examination of SWITRS data for Hemet revealed a significant number of right-of-way violations and speeding-related crashes. Many of these crashes were preventable through engineering changes and aggressive enforcement of existing laws. The use of accurate and timely information was critical for performing engineering studies, enforcement activities and budget planning. However, city planners had limited or non-existent staff time to manually accumulate, maintain and evaluate relevant crash data, to assist with the prioritization of safety improvements at high-collision locations.

GOALS AND OBJECTIVES
To reduce the frequency and severity of traffic crashes occurring in Hemet, the city's Department of Public Works developed a Geographic Information System (GIS)-Based Automated Collision Mapping System and Traffic Census in 2000. Objectives of the program are to:

• Provide transportation engineers and law enforcement personnel with current, comprehensive and accurate data on which to base engineering, enforcement and other traffic safety-related decisions
• Conduct traffic counts at selected high collision locations
• Install a hardware/software system providing citywide automated mapping capabilities, and producing a current report identifying the number and severity of crashes at the city's ten most critical locations
• Establish an electronic linkage between the Hemet Police Department and the Department of Public Works enabling each to share the traffic-related data
• Train two staff members to use and maintain the system software

STRATEGIES AND ACTIVITIES
Hemet Public Works officials hired a local vendor and consultant to expand the city's existing data collection system to include GIS-mapping capabilities. A software system was developed to provide geographic information in digital format on areas of the city identified as high-collision locations. Data from crash records was transferred from the police records management system into the new GIS-based database. Traffic count data was collected at a variety of intersections throughout Hemet, and also incorporated into the new database. Geographic and image data were then merged with the statistical data, to provide a layered map of the city.

The GIS-based database calculates crash rates for selected intersections, for comparison to acceptable standards. The system has graphics capabilities, to provide automated mapping for reports on intersection or mid-block crash rates, within a user-defined time frame. Both police and public works data are accessible for use in identifying hazardous traffic conditions.

RESULTS
Since its development in 2000, the GIS-Based Automated Collision Mapping System and Traffic Census has been used by the Hemet police and public works departments to identify ten street segments with the highest incidence of motor vehicle crashes, and primary collision factors associated with each. The Hemet Police Department systematically analyzes this data to support a selective traffic enforcement program. The GIS database has reduced the time needed to identify and analyze high crash locations and generate special statistical analyses by 50 percent, from 48 hours to 24 hours. Police department and engineering staff have received training to operate the GIS-based system.

Law enforcement personnel and engineering staff from the public works department continue to meet on a regular basis to discuss local traffic issues and solutions.