Warning lights on channelizing devices
Iowa does not use either Type A or C lights on any lane line and taper channelizing devices. ONLY drums are used in the tapers and either 42 inch channelizers (tall retroreflective cones) or vertical panels are allowed on lane lines. For daytime ONLY lane closures, cones may substitute for all of the channelizing devices.
Type A warning lights are used on Type III barricades on Road Closures and on-site detours.
Only Type A (or when attention is needed to daytime, Type B) warning lights are used on very select signs, such as SIGNAL AHEAD signs. Warning lights are generally not used on advance warning signs.