ORINDA — A 2-year-old girl was seriously injured Monday evening after her mother crashed her car on Highway 24 and then was struck along with the toddler while trying to cross the highway, authorities said.

The mother, a 24-year-old woman from Antioch, was suspected of drunken driving when she crashed into the center divide at 9:55 p.m. on eastbound Highway 24 near St. Stephens Drive, according to California Highway Patrol Officer John Fransen.

The pair were later hit by a Mercedes-Benz while crossing the highway, Fransen said. The driver of the Mercedes drove off.

Arriving CHP officers first saw the woman’s Honda Odyssey, then heard the girl crying for her mother, Fransen said. The mother and daughter suffered major injuries.

The mother, whose name was not released, is under investigation for driving under the influence and child endangerment.

Meanwhile, police are looking for the driver of Mercedes. Officials said the car has damage to its passenger-side headlight and passenger-side rearview mirror.

Anyone who witnessed the incident is asked to call the CHP at 925-646-4980.