According to Federal Highway Administration (FHWA) statistics, speed is a contributing factor in over 30% of fatal work zone crashes. Reducing speeds entering and through the work zone is one of the key strategies to reduce incidents and fatalities of motorists and workers in work zones. The use of Work Zone Digital Speed Limit Signs (VSL) and the combination of Digital Speed Limit with Speed Feedback displays have proven to slow motorists’ speeds in work zones.
The FHWA’s Proven Safety Countermeasures section has recently published a study stating how VSLs can reduce crashes on freeways up to:
The Work Zone Digital Speed Limit Sign (WZDSL) has been extremely effective in several states to reduce speeds “When Workers Are Present”. The two, 18” white LED speed display mounted to a MUTCD speed limit sign combined with two, 12” flashing beacons reduced speeds by up to 14 MPH (22.5 KM /H) when combined with presence lights on work zones at night, according to studies conducted independently by North Carolina DOT and Purdue University. When Workers Are Present, the two-digit speed limit will be reduced to the work zone speed limit and the two flashing beacons will be activated. When workers are not present, the two-digit display will display the posted speed limit.
