I drive on I-5 in California, and the exit signs posts if there is a jail, state mental hospital, prison, detention center at that particular off ramp. Is there a policy where this is required? Why are incarceration centers posted on freeway exits?
edit: Can you please cite a policy that requires these detention centers to be posted? Is it a federal policy or a California State policy?


To mark where it is for anyone who needs to to there. Maybe so you are also aware to not pick up hitchhikers in the area, as they may be escapees.