Emergency responders were called just after midnight to westbound Highway 80 near the Appian Way exit after receiving reports of the crash, according to Pinole Fire Battalion Chief Brian Lowry. Arriving crews found a Dodge Durango on its roof blocking the freeway's two right-hand lanes.
Investigators learned that the car had been traveling south on the Appian Way overpass when the driver lost control of the vehicle, crashing through a concrete overpass guardrail and falling about 25 feet onto its roof, Lowry said.
The fall partially collapsed the car's passenger compartment.
However, the driver, a 20-year-old Concord man, and his passenger, another Concord man, 21, were both able to exit the car without any help and suffered only minor injuries.
Emergency responders treated both men at the scene and an air ambulance that had been called to the scene was cancelled.
Pinole police Sgt. Rich Jensen said that the driver showed signs of alcohol intoxication and was arrested on suspicion of DUI.
Police were not releasing the driver's name as of 6 a.m., and the circumstances surrounding the collision remain under investigation.
Caltrans crews replaced the overpass guardrail damaged in the crash, Jensen said.