Flashing Arrowboards in Advance of Freeway Work Zones

The results of controlled field studies conducted by the Texas Transportation Institute to evaluate the effectiveness of flashing arrowboards located in advance of lane-closure work zones are reported. The distances in advance of the work zone ranged from 450 to 4000 ft. The effects of the supplemental arrowboard were compared with the effects of arrowboards placed in the closure at the end of the taper in each blocked lane. The results indicate that a supplemental arrowboard placed in advance of the beginning of a taper can be extremely effective in shifting traffic from the closed lane if the sight distance to the arrowboard improves the effective sight distance to the work zone. The supplemental arrowboard can be placed up to 2500 ft in advance of the taper to increase the effective sight distance to the work zone. Placement more than 2500 ft in advance of the work zone may result in drivers moving back into the blocked lanes.