Work zone speed limit

In Indiana:
Speed are reduced based on the volume of traffic, existing posted speed, and type of project (e.g., lane closures or restrictions).
Normally speed reductions affect only interstate roadways, but could possibly apply on some high-volume state roads.
Speed reduction messages are given to motorists by ground-mounted construction signs, message boards, worksite speed limit signs, etc.
Most of the time reduced speed is in effect only while workers are present, but again there are times when conditions exist that warrant it to be reduced all the time during construction.
The existing (normal speed) black-and-white speed limit signs are covered if speed is reduced. If the roadway is allowed to return to the normal speed at night or other times, then the reduced speed limit signs are covered and the existing ones are uncovered.
INDOT requires flashing beacons on worksite speed zone sign assemblies. These signs state that the reduced speed is in effect only when flashing. Speed limits posted with only an orange advisory plaque attached to a construction sign and without a flashing beacon are not enforceable by troopers as are the worksite speed zone signs.