CA AB1426

Prohibits joint powers agencies from constructing, funding, or operating major thoroughfares within a defined "avoidance area" in Southern California that includes San Onofre State Beach and the Richard H. and Donna O'Neill Conservancy.

Restricts the Department of Transportation's authority to approve, permit, or authorize construction of major thoroughfares in the avoidance area in accordance with a 2017 protective agreement.

Bans state agencies, cities, counties, and other entities from constructing, funding, or authorizing roads that encroach on San Onofre State Beach or the Richard H. and Donna O'Neill Conservancy, with exceptions for visitor/management roads, existing road improvements, and Interstate 5 widening.

Allows limited encroachments on the Richard H. and Donna O'Neill Conservancy's northwestern boundary for covered activities under the Orange County Southern Subregion Habitat Conservation Plan if impacts do not exceed 10 percent of anticipated levels.

Codifies protections established in a 2016 legal settlement agreement between the Attorney General, State Parks Commission, and transportation agencies that prevented a proposed tollroad project through the protected areas.