Regional High Injury Network


High injury networks (HINs) include stretches of roadways where the highest concentrations of collisions occur on the transportation network. The HIN is intended to show where fatal and serious collisions are occurring in the region. The HIN, however, is not an assessment of whether a street or location is dangerous. Rather, the HIN suggests which corridors within a transportation network carry a higher risk of injury. When developing an HIN, jurisdictions typically want to identify a subset of the network where the most collisions are occurring (>50%). Developing an HIN can prove helpful for a variety of reasons, including:

  • Determining geographic areas where crashes are concentrated, and the causes of these crashes, so that efforts can be focused on the most challenging areas and crash factors.

  • Strengthening collaboration to focus street improvements and education campaigns (e.g., Go Human) along the HIN.

  • Prioritizing investments within these areas to reduce collisions.

Through case studies from the Cities of San Francisco and Los Angeles, Oregon Metro, and the Portland Bureau of Transportation, SCAG developed a methodology to map a regional HIN. To identify where most of the collisions are occurring, SCAG created an HIN at a regional scale utilizing a five-year dataset from U.C. Berkeley’s Transportation Injury Mapping System (TIMS 2010-2014). This interactive story map identifies the high injury network for the SCAG region by modes. Although SCAG’s Regional Safety Existing Conditions Report provides crash rates at the regional and county levels, the HIN is not normalized by vehicle miles traveled (VMT) or by population, as would be done to create crash rates. The HIN crash scores are purposefully not normalized by VMT or population because the intent was to identify corridors with the highest concentrations of serious injury and fatal crashes, compared to the rest of the county, no matter the number of VMT or population. This intent is tied directly to achieving our Towards Zero Deaths-related safety targets and to help local jurisdictions focus on improvements where they are most needed. SCAG has identified cities in our region that are a part of SCAG’s high injury network. SCAG aims to work closely with these cities to identify safety concerns, reduce fatalities, and serious injuries, and in turn achieve our regions safety targets. While developing HIN at a regional level helps in identifying cities in the SCAG region with safety concerns, it is recommended that cities develop an HIN at the city level to identify concentrations of collisions. Details on High Injury Network mapping are provided in the Transportation Safety and Security Technical report (linked above) and at Connect SoCal.

View HIN Interactive Story Map