High injury networks (HINs) include stretches of roadways where
the highest concentrations of collisions occur on the
transportation network. An HIN is intended to show where fatal
and serious collisions are occurring in the region. An HIN,
however, is not an assessment of whether a street or location is
dangerous. Rather, an 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:
- Identifying areas of need;
- Providing agency staff with more information on where they
can focus limited resources;
- Providing opportunities to understand how communities of
concern or disadvantaged communities are impacted by higher rates
of collision and serious injury; and
- Assisting with building greater public and political support.
In 2018, SCAG developed its first regional HIN. In developing the
HIN, SCAG reviewed HIN methodologies for a variety of
jurisdictions including Los Angeles, San Francisco, Portland, and
Portland Metro. SCAG borrowed elements from their approaches to
develop one that could work for the entire region. To learn more
about SCAG’s regional High Injury Network, click here.
In 2020, SCAG convened a statewide working group to develop
recommendations for High Injury Network (HIN) statewide guidance.
The group was formed from members of the Strategic
Highway Safety Plan (SHSP) Bicycle and Pedestrian Challenge
Teams. This work was motivated by recommendations from
California’s Zero Traffic Fatalities Task Force and
culminated in the development of this
report, which includes a review of
California HINs developed at the city, county, and metropolitan
planning organization levels of government, and provides details
on which components were included in each HIN and how they were
created. Based on HINs reviewed, the report presents
recommendations for statewide guidance on a definition and
methodology for HINs. In September 2021, the report was shared
with Caltrans and staff are currently reviewing the report and
considering how the recommendations can be institutionalized into
statewide guidance.
