A 17-year-old driver was seriously injured Monday morning in a single-car wreck in east Cobb County.

The driver, who has not been identified, was heading eastbound on Lower Roswell Road and crashed his 2008 Mitsubishi into a tree near the Chattahoochee River, said Cobb Police spokesman Sgt. Dana Pierce. A passerby saw the wreckage and notified police.

Pierce said when officers arrived at the scene the driver had left the vehicle and was found under a nearby bridge. He was airlifted to a local hospital for treatment.

Pierce said toxicology tests would be conducted on the driver. He did not know if the teenager was heading to school when he wrecked.