(This article on work zone safety is reproduced from the July 1988 (Volume VI, No. 7) issue of the TranSafety Reporter, published and edited by Roy W. Anderson, P.E. To find summaries of legal cases related to highway work zones, please check on-line editions of "Road Injury Prevention and Litigation Journal" at this web site.)

One of the very valuable traffic control devices for use in work zones is the flashing arrow sign. Unfortunately, like many of the other traffic control devices, it is often misused, causing motorist confusion or surprise and injuries to workers, pedestrians, or motorists. Another serious problem is when motorists see it incorrectly used. They may not understand its meaning and later disregard the message when used properly.

Fig. 1. Virginia DOT maintenance crew driving slowly on major urban arterial in right lane with arrow flashing to the right directing motorists to pass to the right over the curb. The arrow should have been flashing to the left on this 4-lane road.

Fig. 2. The truck is stopped to pick up a "work zone" sign. Arrow continues to flash and direct traffic to the right. "Slow" sign on truck is obstructed by an arrow board.

Fig. 3. Worker loads sign as arrow continues to flash to the right.

Changeable message signs are coming into vogue in work zones. The potential benefit of such signs and messages is great, particularly when advising of current traffic conditions, work locations and lane(s) status. More study is needed on effective messages and their use.

Fig. 4. On California I-80 two messages appear in sequence on the same sign HEY YOU--SLOW DOWN and SHORT MERGES AHEAD.

Fig. 5. Almost transparent warning sign with small letters is hardly legible at 100 feet on this 8-lane section of California I-80. Placement only at the closure is inadequate warning.

Fig. 6. A DO NOT ENTER sign is used by a utility contractor to warn motorists of a 6-foot deep excavation on this major arterial (posted speed 45 mph) in the city of Lawton, Oklahoma. The Type I barricade has a bag of sand on the top for stability. Sand bags can penetrate the windshield of an impacting car and cause injury or death. The soil embankment from the excavation is piled in the median between opposing traffic lanes creating a hazard to a motorist who enters the median during an emergency maneuver.

Fig. 7. The same excavation undermines the pavement, creating a potential for pavement collapse.