Investigators for the California Highway Patrol said a 37-year-old Pleasant Hill man was behind the wheel of an SUV that swerved out of control along westbound Highway 24 at Camino Pablo Tuesday, striking a tree.
The crash was reported around 11:40 a.m. Rescuers were hampered by the location, which was difficult to see from the roadway, and traffic through the area was blocked for some time as the vehicle was untangled and recovered.
Nathaniel Greenan was pronounced dead at the scene, an investigator said.
Contra Costa County Animal Services personnel were called to the scene to pick up a dog that was inside the car and survived the crash.
Although some witnesses reported seeing Greenan's Lexus SUV moving erratically just before the crash, no other vehicles were involved, according to the CHP.