Code of Alabama
Division 2 - Lights, Lamps and Reflective Devices.
Section 32-5-247 - Reflective Devices for Slow-Moving Vehicles - Mounting.

The device shall be mounted on the rear of the vehicle, implement, or mobile equipment broad base down, not less than three feet nor more than five feet above the ground, measuring to the lowest portion of the device and as near the center of the vehicle, implement, or mobile equipment as practicable.