The Modesto Area Office of the California Highway Patrol is responsible for the patrol of all freeways, roadways, and unincorporated areas within Stanislaus County. Geographically, Stanislaus County covers 1,521 square miles and has a population of approximately 510,385. Stanislaus County has an estimated 475,000 registered vehicles.State Route 99 and Interstate 5 are both heavily traveled routes in Stanislaus County. Motorists also travel along seven additional state routes, including State Route 4, State Route 33, State Route 108, State Route 120, State Route 132, State Route 165, and State Route 219. State Route 132 through Stanislaus County is known to have some of the most dangerous stretches of two-lane highways in the state.