Cal. Pub. Resources Code § 42700
The Director of Transportation, upon consultation with the board, shall review and modify all bid specifications relating to the purchase of paving materials, and base, subbase, and pervious backfill materials, using recycled materials. The recycled materials shall include, but are not limited to, recycled asphalt pavement, crushed concrete subbase, foundry slag, asphalt flux produced from the reprocessing or re-refining of used oil, and paving materials utilizing recycled materials, including, but not limited to, crumb rubber from automobile tires, ash, and glass and glassy aggregates. The specifications shall be based on standards developed by the Department of Transportation for recycled paving materials and for recycled base, subbase, and pervious backfill materials. The standards and specifications shall provide for the use of recycled materials and shall not reduce the quality standards for highway and road construction.
Ca. Pub. Res. Code § 42700