Officers responded to a report of an injury crash on Treat Boulevard just west of Bancroft Road shortly after 6 p.m., according to the Walnut Creek Police Department.
An investigation showed that the driver and sole occupant of a pickup truck was traveling east on Treat Boulevard when he lost control of the vehicle and crossed a median into westbound lanes, police said.
The driver, who was later determined to be drunk, then steered the truck back into eastbound lanes and drove onto the sidewalk.
There he struck Moorhead and crashed into a pine tree.
Moorhead was treated by emergency responders at the scene and then taken to John Muir Medical Center where she was pronounced dead shortly after.
The driver was arrested at the scene for DUI and taken to a hospital to be treated for his injuries.
He was later booked into county jail on suspicion of vehicular manslaughter.