At 7:30 a.m., officers responded to a report of a vehicle blocking the driveway of a fire station on O'Hara Avenue, city officials said on the City of Oakley Facebook page.
The victim appeared to be the driver of the vehicle, who may have been driving to the fire station to seek medical treatment.
The Contra Costa Sheriff's Office is leading the investigation.
Investigation into Oakley death is continuing. Possibly related to a pre-existing medical condition. No preliminary indication of foul play.— CoCo Sheriff PIO (@cocosopio) March 20, 2016