A head-on collision injured both drivers and split a pickup truck in half Saturday morning just east of I-680 on Highway 84.
The crash occurred at 10:36 a.m.
Alameda County Fire Battalion Chief Stephanie Radecke said a Toyota Tundra and a U-Haul truck crashed head-on, tearing the Tundra in half and rolling the U-Haul over on its side.
One driver was transported to a hospital by helicopter and the other was transported by ground ambulance, Radecke said.
A wet road may have been a factor in the collision, police said.
The crash created debris and one of the vehicles also leaked fuel onto the roadway, causing Hwy. 84 to be closed for several hours while crews cleaned up the scene.
Firefighters from the Alameda County Fire Department, Cal Fire and the Livermore-Pleasanton Fire Department responded to the incident.