Former Tennessee Titans offensive coach Todd Downing has turned himself in ... and will begin serving his 48-hour sentence stemming from his DUI arrest in November.
TMZ Sports has confirmed ... Downing surrendered to the Williamson County Sheriff's Department Tuesday and is in police custody at the Williamson County jail.
Tennessee Highway Patrol officers claimed Todd was "traveling at a high rate of speed" on Interstate 65 at around 2:30 AM.
Downing was arrested in November ... just hours after the Titans defeated the Green Bay Packers on Thursday Night Football.
Titans Offensive Coordinator Todd Downing Arrested For DUI After Win Over Packers
Downing, 42, was arrested and booked on DUI and speeding charges.
At the time of Downing's arrest, head coach Mike Vrabel said the Titans have a policy in place that provides rides to members of the org. if they ever need one.
Downing has been in the NFL since 2003 ... starting out as a football systems analyst with the Vikings before working for the Rams, Lions, Raiders, and Titans.
The Titans fired Downing in early January.