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 California, speeding in a construction or work zone is considered a serious offense. The state enforces what is known as the 'double fine zone' in areas where construction, maintenance, or utility work is taking place. This means that fines for speeding in these zones are doubled when workers are present and the zone is properly marked with signs. California Vehicle Code Section 22362 specifically addresses speed limits in construction and maintenance zones, requiring drivers to adhere to the posted speed limits regardless of the standard speed limit for the area. The law applies to both state highways and local streets where work is being conducted. Additionally, California Vehicle Code Section 42010 allows for enhanced penalties for traffic violations, including speeding, in construction or work zones. Drivers should be aware that the reduced speed limit in a construction zone remains in effect until they pass a sign that indicates the end of the zone and an increased speed limit. Violations can result in hefty fines and points on the driver's license, which can impact insurance rates and driving privileges.