California’s State Highway System (SHS) has approximately 15,100 center line miles. The California Department of Transportation (Caltrans) manages more than 50,000 lane miles of highways and freeways and is comprised of 12 districts. In 2012, the Federal Highway Administration (FHWA) developed the California Roadway Departure Safety Implementation Plan (RwDSIP) for Caltrans.

The RwDSIP identified a total of 7,198 candidate locations for countermeasures using two different approaches: 1) a systematic approach and 2) a comprehensive approach. The systematic approach identified crash types that specific countermeasures were designed to impact and selected clusters of locations where the targeted crashes exceeded the designated threshold, which varied for each countermeasure. Roadway characteristics and traffic volumes also were considered in candidate location selection.