A man died early Sunday morning when his speeding silver Infiniti crashed through a retaining wall on I-285 in Cobb County.

Cobb County police report the 2003 Infiniti G35 sped southward along South Cobb Drive around 2:30 a.m. before leaving the roadway, dropping into a ravine and up onto I-285 westbound. The car then plowed through the retaining wall before stopping in the eastbound 285 lanes.

The driver, identified as 51-year-old Walter Alan Mitchell of Atlanta, died at the scene.

The wreck closed the interstate before dawn, but all lanes had reopened by 6 a.m.