Typical Problems in Highway Work Zones and

Their Solutions

The following common problems in work zones can increase the danger to motorists and workers.

• Signs left up when no work is going on. When drivers see work zone signs but no work activity, they lose respect for such signs. Before leaving the work zone, crews should keep up only those signs necessary to warn motorists of the road conditions. Especially important is the removal of the “Flagger Ahead” sign.

• Improper signs and sign stands. Wooden and heavy metal signs and sign supports can cause considerable harm in minor accidents. They should be “crashworthy,” which means that they conform to NCHRP Report 350. Suppliers can provide certification that signs and supports meet “350” requirements.

• Too few cones and barrels. There must be enough cones or barrels to define the transition area tapers clearly. The minimum number depends on taper length and traffic speed. They should be evenly spaced along the taper length.

• Devices too small. In greater than 35 mph work zones, and in all work zones at night, cones must be 28 inches high. They must have two retroreflective stripes or lights. In 35 mph and less work zones, cones can be 18 inches high with one retroreflective stripe. Barrels must be at least 36 inches high and 18 inches wide. They must be orange with at least two white, 4 to 6 inch wide, retroreflective stripes. Barrels can have weight in the bottom, but not be filled.

• Non-reflective devices. All signs and other devices must be retroreflective and visible at night.

• Flaggers using flags. Flags should be used for emer­gency use only. Flaggers should use STOP/SLOW paddles, and hand signals when necessary. Paddles must be 8-sided (not round), retroreflective, at least 18 high and wide, and on a rigid handle.

• Complacent Flaggers. Flagging can be boring and tir­ing, but flaggers must stay alert and pay attention at all times. One moment of complacency can result in injury to motorists, passen­gers, workers, and/or the flagger.

• Poor Flagger location. Flaggers should be on the outer edge of the travel lane they are directing. They should stand alone, away from equipment and other workers. They should stay out of shadows and be visible to drivers well in advance of their location.

• Lack of termination signs. As a courtesy to drivers, all lane closures should end with an “End Road Work” sign.

References:
MUTCD, http://mutcd.fhwa.dot.gov
Ten problems in highway work zones, Okla­homa LTAP News, October 2004, p. 8
Slides from Workzone Traffic Control, UNH T² Workshop

Return to Spring 05