Officers responded to reports of a collision involving a pedestrian at the intersection of Grant Street and O'Hara Avenue around 8:15 a.m., police said.
When they arrived, they learned that a car driven by a 43-year-old man had hit a 74-year-old woman entering a crosswalk. The car then hit a curb, a fire hydrant and a sound wall before coming to a stop, according to police.
The woman was taken to Sutter Delta Medical Center in Antioch where she was pronounced dead.
A girl who was riding in the car suffered a minor abrasion to her neck from the seat belt but did not require medical treatment, police said.
The driver was found to be driving under the influence of a controlled substance, and a search of the car turned up what appeared to be methamphetamine and drug paraphernalia, according to police.
The man, whose name has not been released, was arrested on suspicion of vehicular manslaughter, child endangerment, DUI resulting in injury and drug offenses.
He was taken to county jail in Martinez.
Police are continuing to investigate the collision.
Anyone with information about this case is asked to call Brentwood police Officer Justin Luo at (925) 778-2441 or (925) 634-6911.