Ramp metering is present at all onramps, and is used southbound in the morning and northbound in the evening.

The route begins as a freeway at Interstate 680 at the Pleasant Hill–Concord border.

It then heads north into Concord, meeting Clayton Road, Concord Avenue, Grant Street, and Olivera Road before meeting its north end at State Route 4 just west of the former Concord Naval Weapons Station.

[2] SR 242 is part of the California Freeway and Expressway System,[3] and is part of the National Highway System,[4] a network of highways that are considered essential to the country's economy, defense, and mobility by the Federal Highway Administration.

[5] The entire route is in Contra Costa County.