San Diego Management & Monitoring Program

Impact of Wildlife-Vehicle Conflict on California Drivers and Animals

Type: report

Article abstract: Using observations of reported traffic incidents and carcasses the Road Ecology Center estimates the total annual cost of wildlife-vehicle conflict (WVC) in California to be at least $276 million, up 20% from the year before. This report includes maps of WVC hotspots, discusses impacts to wildlife and people from WVC, and ranks highways in each Caltrans District for financial cost of WVC (spoiler, I-280 in District 4 is the costliest). Projects to reduce WVC can be the most effective of any safety project, with effectiveness often >90%. In addition, only 1- 2% of California’s transportation budget, including the new Senate Bill 1 funds, would be required to carry out these safety projects. This report provides an overview of wildlife-vehicle conflict (WVC) hotspots on California highways in 2015 and 2016, based on a combination of traffic incidents involving wildlife that were recorded by the California Highway Patrol (CHP) and carcass observations reported to the California Roadkill Observation System ( Because Caltrans does not systematically record where they pick up the tens of thousands of wildlife carcasses per year they dispose of from state highways, these data are not included. Analytical details are available from Fraser Shilling ( upon request.

Number of pages: 20

Authors: Shilling, Fraser; Waetjen, David; Harrold, Kathryn;

Year: 2017

Keywords: California; connectivity; connectivity corridors; habitat connectivity; road and anthropogenic barriers; road ecology; roadkill; roads;

Threats: Loss of connectivity