Wildlife vehicle collisions (WVC) are problematic globally as traffic volumes increase with expanding road infrastructure. Wildlife populations become degraded as species experience direct mortalities. While these issues are pursued in the growing wildlife connectivity world, there is no quantitative method or published estimates of total roadkill from WVC at a large spatial extent. We described and applied a method for estimating annual WVC in California for four large mammals: mule deer, puma, black bear, and elk. We used California Roadkill Observation System (CROS) for roadkill data from 2015-2024 and GenEst to fit models. We measured rates of carcass observation and estimated persistence, effort and search efficiency based on literature. We estimated that 39,838 (CI 32,871-53,778) mule deer, 579 (CI 313-9750) pumas, 3,368 (CI 2,279-5,031) black bears, and 340 (CI 219-504) elk were killed per year on paved roads. These estimates represent 9% of deer, 13% of puma, 5% of black bear, and 3% of elk statewide populations. This highlights that WVC may contribute significantly to local and statewide population declines across large mammal species in California. WVC datasets are essential to understanding population dynamics and states must reduce rates of WVC to protect populations.