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Updated: Mar 3, 2026

Collecting Sleep, Circadian, Fatigue, and Performance Data in Complex Operational Environments
Published on: August 8, 2019
Time of day effects on railroad roadway worker injury risk
Clark Calabrese1, Bianka Mejia1, Catherine A McInnis1
1U.S. Department of Transportation, Volpe National Transportation Systems Center, 55 Broadway, Cambridge, MA 02142, USA.
Introduction:
The purpose of this study is to examine how time of day affects injury risk of railroad maintenance of way employees and signalmen (roadway workers). Railroads reported 15,654 serious roadway worker injuries between 1997 and 2014. Roadway workers primarily work outdoors on or near railroad tracks and frequently encounter hazardous conditions. To avoid closing an active rail line during peak hours, railroads sometimes require roadway workers to work at night. Previous studies of roadway worker injury have not adequately accounted for exposure to time of day effects, nor have they investigated the human factors issues contributing to roadway worker injury.
Method:
The Federal Railroad Administration (FRA) database of injury reports provided data for circadian rhythm models of the odds of fatal and nonfatal injuries. The FRA database and fatal injury investigation reports also permitted an analysis of the circumstances and the human factors issues associated with injuries that occur at different times of day.
Results:
Odds of injury increased during nighttime work. The odds of nonfatal injury for both roadway worker crafts rose above 9:1 in the early morning hours. The relative odds of a fatal injury also increased significantly at night. A human factors analysis suggested that during all three shifts most nonfatal injuries involve workload, but workload was not identified as a factor in fatal injuries.
Conclusions:
Nighttime work is more hazardous for roadway workers than daytime work. Several factors related to fatigue and other conditions appear to increase the risk of injury during the outdoor, nighttime work required of roadway workers.
Practical Application:
For practical reasons, nighttime roadway work is sometimes unavoidable. Therefore, new practices for nighttime work must be developed to adequately address fatigue and protect roadway workers from harm.
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