California postmile

Location marking system on highways in California, US

California uses a postmile highway location marker system on all of its state highways, including U.S. Routes and Interstate Highways. The postmile markers indicate the distance a route travels through individual counties, as opposed to mileposts that indicate the distance traveled through a state. The postmile system is the only route reference system used by the California Department of Transportation (Caltrans). The system was operative by 1966.

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