Robert Woods has been charged with murder with an enhancement for the use of a knife in connection with the slaying of 46-year-old Elnora Caldwell, also of Oakland, according to the district attorney's office.
Caldwell had an active restraining order against Woods at the time of the attack.
Prosecutor Harold Jewett has alleged Woods killed Caldwell because he was angry that she was trying to divorce him and he wanted to get back together with her.
The sheriff's office learned of the attack at about 6:15 p.m. when witnesses began calling for help, Contra Costa County Sheriff's Capt. Daniel Terry said.
Witnesses told investigators they saw a man, later identified as Woods, push the victim out of a pickup truck in the 1000 block of Fish Ranch Road near the Caldecott Tunnel, the sheriff's office said.
Several people attempted to help the woman while others called 911.
Caldwell was taken to John Muir Medical Center in Walnut Creek where she died from her injuries.
Terry said one motorist followed Woods' pickup truck, but lost sight of it.
Woods then allegedly went to Caldwell's house, where her 21-year-old son saw him.
The son, who knew his mother had a restraining order against Woods, became upset when he saw Woods at the house and armed himself with a pair of scissors, Jewett said.
The son chased Woods out of the house and, not knowing that his mother had been killed, broke out a window in Woods' pickup truck with the scissors, Jewett said.
Woods then drove about a block and a half away from Caldwell's house, where he found an Oakland police officer and turned himself in.
He was booked into the Contra Costa County jail and his bail was set at $1 million.
He is scheduled to return to court Dec. 17 t set a date for a preliminary hearing.