U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
Increasing the Clear Zone prevents crashes
of all fatal crashes occur at cuves
of all fatal crashes at curves are roadway departure crashes
Source: Fatality Analysis Reporting System (FARS)
Roadside design improvement at curves is a strategy encompassing several treatments that target the high-risk roadside environment along the outside of horizontal curves. These treatments prevent roadway departure fatalities by giving vehicles the opportunity to recover safely and by reducing crash severity.
Roadside design improvements can be implemented alone or in combination and are particularly recommended at horizontal curvesâ€”where data indicates a higher-risk for roadway departure fatalitiesâ€”and where cost effectiveness can be maximized.
In cases where a vehicle leaves the roadway, strategic roadside design elements, including clear zone addition or widening, slope flattening, and shoulder addition or widening, can provide drivers with an opportunity to regain control and re-enter the roadway.
Since not all roadside hazards can be removed at curves, installing roadside barriers to shield unmovable objects or embankments may be an appropriate treatment. Roadside barriers come in three forms: