Wildlife and traffic don’t mix well. Wildlife-vehicle conflict refers to the mortality, aversion, and fragmentation effects of traffic on wildlife (mammals, birds, herpetofauna). The adverse impact of traffic on California fauna has been at the center of recent legislation. The Road Ecology Center has collected >100,000 observations of wildlife-related crashes and roadkilled animals, using the California Roadkill Observation System (CROS, https://widlifecrossing.net/california) and the California Highway Incident Processing System (CHIPS). These observations come from hundreds of agency, academic, NGO, and individual scientists, and CHP officers and have species identity accuracy of 97%. Using these data, combined with wildlife values and crash coefficients, we identified 1,717 one-mile segments of state highway where fencing would cost less than the cost of WVC in those segments. We further identified >150 segments where fencing + under-crossings (10’ box culvert, 4-lane highway) would cost less than crashes in those segments. These results provide an immediate source of information for Caltrans and other state agencies to meet recent legislative requirements, such as AB 2344, and apply for federal funding under the Bipartisan Infrastructure Law. These data would also be useful for municipal and regional entities to use in local conservation planning.