Paved Shoulders on Primary Highways in Iowa: An Analysis of Shoulder Surfacing Criteria, Costs and Benefits

Abstract

Almost 50 percent of rural fatal crashes in the United States occur on tangent alignments and level roads away from intersections. Single-vehicle run-off-the-road crashes are the highest crash type in rural areas nationally. Fatigue, drowsiness, and distracted driving are major contributing factors to single-vehicle run-off-the-road crashes. These types of rural accidents appear to be rising with an increase in inattentive driving and more long-distance commercial travel.\nThe scope and seriousness of this type of crash is very significant. The estimated annual cost of run-off-the-road crashes in the United States is $80 billion. In addition to these costs, there are the hidden costs of emotional distress and family disruptions.