SAFETY STUDY
Adopted: May 12, 1992
HIGHWAY WORK ZONE SAFETY 
NTSB Number: SS-92/02
NTIS Number: PB92-917005 
SYNOPSIS
The number of fatalities that occurred in highway work zones increased from 489 in 1982 to 780 in 1988. Concurrently, total spending on highway construction increased from about $32 billion to about $52 billion. The Nation's interstate system, for the most part, has been completed. As the infrastructure ages, the number of maintenance and construction zones to repair and to replace sections of the network can be expected to increase. Further, growth in traffic volume has required that roadway capacities be increased to provide a more desirable level of service to motorists; thus construction for this reason can also be expected to increase. The available data indicated that unless additional efforts were made to reduce work zone accidents, the number of fatalities would continue to increase. Because of these factors, the National Transportation Safety Board became increasingly concerned about the adequacy of traffic safety in work zones and initiated a study in 1988 concerning work zone related accidents. More than 40 accidents were investigated during the next 2 years, and previous work zone accidents investigated by the Safety Board were reviewed.

In July 1990, as the review of the accident cases neared completion, the Safety Board conducted a major investigation of a work zone accident near Sutton, West Virginia. Eight persons were killed in the accident, and five vehicles were either destroyed or severely damaged. In Its statement of probable cause, the Safety Board determined that contributing to the cause of the accident was the less than optimal work zone control devices and procedures used at the site. The accident underscored the Safety Board's concern regarding safety in work zones, and several safety recommendations were issued to the West Virginia Department of Transportation and the Federal Highway Administration to improve work zone safety.

Additional investigations of work zone accidents were conducted in 1990 and 1991, as they occurred. A review of these accidents and the Sutton, West Virginia, accident raised additional work zone safety issues that are discussed in this study.

The safety issues discussed in this study are:

· the usefulness of work zone accident data;

· the hazards of two-lane, two-way operations without positive separation of traffic on a normally divided highway;

· the use of truck-mounted attenuators in moving maintenance operations and at long-tem construction sites;

· the placement of flaggers;

· the need to identify design changes in work zones that will aid drivers with degraded sensory perceptions resulting from aging, inattentiveness, or impairment;

· the lack of compliance with existing guidelines for work zone traffic control devices and procedures;

· the need for a national work zone safety program;

As a result of this study, safety recommendations were issued to the National Highway Traffic Safety Administration, the Federal Highway Administration, and the American Association of State Highway and Transportation Officials.

RECOMMENDATIONS

As a result of this safety study, the National Transportation Safety Board made the following safety recommendations:

to the National Highway Traffic Safety Administration:

Revise the reporting of work zone fatalities to distinguish between persons driving highway maintenance vehicles within work zones and other drivers who crash in work zones while traversing the work zone site. (Class II, Priority Action) (H-92-32)

Review, in conjunction with the Federal Highway Administration, all State accident report forms, select the data elements that comprehensively document work zone accidents, and encourage the States to incorporate these data elements into their accident report forms. (Class II, Priority Action) (H-92-33)

to the Federal Highway Administration:

Review, in conjunction with the National Highway Traffic Safety Administration, all State accident report forms, select the data elements that comprehensively document work zone accidents, and encourage the States to incorporate these data elements into their accident report forms. (Class II, Priority Action) (H-92-34)

Develop a program to collect exposure data for construction work zones on the interstate system. (Class II, Priority Action) (H-92-35)

Conduct research, in conjunction with industry, to determine the effectiveness of truck-mounted attenuators when struck at various angles and offsets and at speeds in excess of 45 mph, and analyze the safety benefits and shortcomings of using truck-mounted attenuators in such high-speed environments. (Class II, Priority Action) (H-92-36)

Eliminate in figure TA-35, 'Mobile Operation on Multilane Road," in the proposed revisions to the Manual on Uniform Traffic Control Devices, the depiction of vehicles equipped with truck-mounted attenuators positioned astraddle pavement edgelines. (Class II, Priority Action) (H-92-37)

Encourage, in cooperation with the American Association of State Highway and Transportation Officials, State highway departments to (1) incorporate headrests and lap/shoulder restraints into the specifications for the purchase of new vehicles given that the vehicles may at times be equipped with truck-mounted attenuators and (2) retrofit existing vehicles used for that purpose. (Class II, Priority Action) (H-92-38)

Revise the Manual on Uniform Traffic Control Devices to require positive separation of opposing traffic when two-lane, two-way operations on one roadway of a normally divided highway are implemented on the Interstate system and incorporate this information into the Traffic Control Devices Handbook. (Class II, Priority Action) (H-92-39)

Revise the Manual on Uniform Traffic Control Devices to provide guidance on the placement of flaggers at work zone sites based on factors such as posted speed limits, actual vehicle speeds, commercial vehicle deceleration rates, road conditions, and topography. (Class II, Priority Action) (H-92-40)

Conduct research to identify design changes in work zones that will aid drivers with degraded sensory perceptions resulting from aging, inattentiveness, or impairment. Use the results of this research to design better and more meaningful work zone traffic advisories and safety features. (Class II, Priority Action) (H-92-41)

Develop, in cooperation with the American Association of State Highway Transportation Officials, a program to enhance compliance with existing guidelines regarding work zone safety features. (Class II, Priority Action) (N-92-42)

Develop, in cooperation with the American Association of State Highway and Transportation Officials, a national work zone safety program that Integrates substantive enforcement and public information and education efforts. Enlist the support of those organizations and associations that can provide expertise in the areas of engineering, enforcement, and education. (Class III, Longer Term Action) (H-92-43)

Refer, in the Manual on Uniform Traffic Control Devices and the Traffic Control Devices Handbook, to the guidance on the applicable uses of truck-mounted attenuators to be incorporated in the Roadside Design Guide. (Class II, Priority Action) (H-92-44)

Determine if a combination of efforts, such as speed reductions coupled with onsite enforcement and positive barriers, may be needed at work zones when commercial vehicles are a relatively large percentage of the average daily traffic. (Class II, Priority Action) (H-92-45)

to the American Association of State Highway and Transportation Officials:

Incorporate, into the Roadside Design Guide, guidance on the applicable uses of truck-mounted attenuators in short-term moving/maintenance operations and at long-term stationary construction sites. (Class II, Priority Action) (H-92-46)

Encourage, in cooperation with the Federal Highway Administration, State highway departments to (1) incorporate headrests and lap/shoulder restraints into the specifications for the purchase of new vehicles given that the vehicles may at times be equipped with truck-mounted attenuators and (2) retrofit existing vehicles used for that purpose. (Class II, Priority Action) (H-92-47)

Develop, in cooperation with the Federal Highway Administration, a program to enhance compliance with existing guidelines regarding work zone safety features. (Class II, Priority Action) (H-92-48)

Develop, in cooperation with the Federal Highway Administration, a national work zone safety program that integrates substantive enforcement and public information and education efforts. Enlist the support of those organizations and associations that can provide expertise in the areas of engineering, enforcement, and education. (Class III, Longer Term Action) (H-92-49)