Two people were injured when their car ran off Highway 88 in Rogers County overnight Friday.
Oklahoma Highway Patrol troopers believe the driver had been drinking alcohol.
According to the OHP, John W. Blanda was northbound when his Lexus failed to make a curve on the south end of Oologah Dam. The car hit a sign and went into some woods, rolling one and three-quarter times and coming to rest on the driver's side.
A trooper told News On 6 the men fell down a nearby ravine after getting out of the wrecked car.
Blanda, 33, was taken by medical helicopter to a Tulsa hospital in serious condition with a head injury, a trooper's report states.
His passenger, 25-year-old Tulsa resident Michael B. Williamson, was taken to the hospital where he was said to be stable with internal injuries.
The investigating trooper said there was an odor of alcohol about the driver, and the cause of the wreck was unsafe speed on a curve.