A survey in 2017 demonstrated that a large number of newts were being killed by vehicles using Alma Bridge Road, most likely during annual breeding migrations to breed in Lexington Reservoir. In order to help determine the effect of this road-based mortality, we conducted a drift fence/pitfall trap array study to estimate the number of adult Taricha torosa and Taricha granulosa attempting to cross Alma Bridge Road during the 2020/2021 breeding season. Drift fence/pitfall trap arrays were installed and daily surveys were conducted. Daily traffic and precipitation data were also recorded. Concurrently, a citizen scientists group conducted road carcass surveys over the entire study area. We analyzed the data to calculate the number of adult newts attempting to cross Alma Bridge Road at the arrays and the road-based mortality rates. Then, with road mortality data provided by the citizen scientists, we estimated the number of adult California newts attempting to cross the road and the mortality rates over the study area during the survey period. We then modeled whether this road-based mortality rate might, if left unabated, lead to a reduction in, and possibly the eventual extirpation of, the local population of newts breeding in Lexington Reservoir.