Ala. Code § 32-5A-375: Use of Photographic Speed Enforcement Systems in Active Work Zones.

A photographic speed enforcement system authorized under this article may be used to detect and record motor vehicle speeding violations in an active work zone. For purposes of this article, “active work zone” means a work zone that satisfies all of the following conditions:

(1) The area is designated by the department or authority as a work zone.

(2) Employees or contractors of the department or authority or construction, maintenance, inspection, surveying, utility, or other workers are present.

(3) Work zone traffic control devices, traffic controls, or warning signs are present to notify motorists and pedestrians of construction, maintenance, inspection, surveying, utility, or other workers in the area.

(4) Not less than two warning signs are placed at least 500 feet in advance of the entrance warning motorists that a photographic speed enforcement system is being operated in the area and that a violation will result in a fine.