A 23-year-old Modesto man was killed early Wednesday when he crashed his vehicle on northbound Highway 99 south of Pelandale Avenue, according to the California Highway Patrol.
The wreck occurred at about 2:35 a.m., the CHP said.
The man was driving a 2007 Chevrolet in the No. 3 lane at an unknown speed when he veered to the left and hit the concrete center divider, the CHP said.
The vehicle overturned and landed on its roof in the dirt median.
The man, who was not wearing a seatbelt, was ejected through the right front passenger side window, the CHP said.
A Stanislaus County Sheriff's deputy was driving by and stopped to assist. The deputy provided CPR to the man, who was later taken to Doctors Medical Center, where he was pronounced dead.
The identity of the man is pending notification of family.
The CHP said it is unknown at this time if alcohol and/or drugs were a contributing factor in the crash, which is still under investigation.