Police arrested a driver who took off after hitting a pedestrian on Murfreesboro Pike.
The wreck happened near Plus Park Boulevard just before 5:30 a.m. Saturday.
Officials said Louis Arturo Centeno Tobar struck a woman who was walking. He then reportedly sped away.
A man who witnessed the wreck followed and detained him until officers arrived.
The woman was taken to Vanderbilt University Medical Center in critical condition.
Officers said damage to the vehicle was consistent with hitting a person, and the driver admitted to the crash.
Tobar was arrested on several charges, including vehicular assault and DUI.