VACAVILLE -- A 22-year-old Oakland woman was killed Sunday when a tree fell on her car as she was driving on Interstate 80 in Vacaville, authorities said.

Kenneisha Dale was driving west on I-80 east of Cherry Glen Road at around 1:40 p.m. when a tree crushed the roof of her 1997 Toyota Camry, according to the California Highway Patrol. She died after suffering severe head trauma, the CHP said.

Dale was wearing her seat belt and driving the speed limit in the slow lane. She was alone in the car, the CHP said.

Authorities are investigating what caused the tree to fall.

David DeBolt covers breaking news. Contact him in Richmond at 510-262-2728. Follow him at Twitter.com/daviddebolt.