National Center for Sustainable Transportation

A key function of a highway network is to maintain access during normal and emergency operations. During wildfire evacuations, first-responders and firefighters depend on highways and local roads for transporting heavy equipment to communities in need. The California Department of Transportation (Caltrans) is expanding vegetation management to begin establishing defensible space zones along California’s nearly 16,000 miles of state highways and in about 230,000 acres of highway right-ofway. However, extended drought, a longer fire season, and higher temperatures brought on by climate change, along with the spread of invasive weeds and dense, dry vegetation, have created new challenges.

The California Department of Forestry and Fire Protection produced a Community Wildfire Prevention and Mitigation Report in 2019 with a methodology to assess wildfire risk. Caltrans and researchers at the University of California, Davis applied these methods to develop a highway-segment-specific prioritization model for vegetation management within highway rights-of-way. The researchers also interviewed Caltrans staff about opportunities for and obstacles to increasing the pace and scale of vegetation treatments. This policy brief summarizes the findings from that research and provides policy implications.

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