The infraction or offense of speeding in a construction or work zone is committed when the driver of a motor vehicle in a marked construction/work zone exceeds the posted speed limit or exceeds the speed limit that is reasonable and prudent under the circumstances or conditions—conditions such as the road (straight, curved, wet, dry, icy, flat, hilly); the weather (clear, foggy, raining, snowing); and the visibility (smoke from a grass fire or a tractor trailer obstructing the view).

Laws vary from state to state and in many states the construction or work zone speed limit only applies when workers are present and the zone is clearly marked with signs. But drivers should be aware that the construction or work zone often extends past where barrels or other barriers have been placed on the road and the reduced speed limit continues to apply until there is a sign indicating an increased speed limit.

Laws regarding speeding in a construction or work zone (and their enforcement) vary from state to state and among cities and towns (local ordinances) and are usually located in a state’s statutes. The penalty for speeding in a construction or work zone is usually a fine and demerit points added to the driver’s license or driving record. But the fines and penalties for speeding in a construction zone are usually much greater than for a typical speeding ticket or citation—for example, fines may be doubled.

In Arizona, speeding in a construction or work zone is considered a serious traffic offense. The state enforces what is known as the 'Double Fine Zone' law, which means that fines for speeding in these zones are doubled when workers are present and the area is properly marked with signs indicating the work zone. The law applies to areas where road construction or maintenance is being conducted, and the reduced speed limits are in effect regardless of whether the construction barriers are visible. The intent is to ensure the safety of both the workers and the motorists. If convicted of speeding in a construction zone, drivers not only face increased fines but may also receive demerit points on their driving record, which can impact insurance rates and driving privileges. It's important for drivers to be vigilant and adhere to posted speed limits, especially in construction zones, to avoid these heightened penalties.