U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000


Skip to content
FacebookYouTubeTwitterFlickrLinkedIn

Safety

eSubscribe
eSubscribe Envelope

FHWA Home / Safety / Proven Safety Countermeasures / Proven Safety Countermeasures - Roadside Design Improvements at Curves

Proven Safety Countermeasures

Printable Version [PDF, 286 KB]
(You may need the Adobe Reader to view the PDFs on this page.)

For more information about this Proven Safety Countermeasure, visit the Office of Safety's Roadway Departure Clear Zones web page.

Roadside Design Improvements at Curves

FHWA treskelion logo.
U.S. Department of Transportation
Federal Highway Administration

FHWA-SA-17-061

Icon representing design improvements on curves.

Roadside Design Improvements at Curves

Increasing the Clear Zone prevents crashes

Illustration shows that extending the clear zone from 3.3 feet beyond the shoulder on a curve to 16.7 feet away from the shoulder provides a reduction in crashes of greater than 22 percent. Extending the clear zone 300 feet beyond the edge of the shoulder provides a crash reduction of greater than 44 percent.

27%
of all fatal crashes occur at cuves

80%
of all fatal crashes at curves are roadway departure crashes

Source: Fatality Analysis Reporting System (FARS)

Shoulder is provided along roadway curve.
Source: Alaska DOT

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 curves—where data indicates a higher-risk for roadway departure fatalities—and where cost effectiveness can be maximized.

Roadside Design Improvements to Provide for a Safe Recovery

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.

Roadside Design Improvements to Reduce Crash Severity

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:


For more information on this and other FHWA Proven Safety Countermeasures, please visit
https://safety.fhwa.dot.gov/provencountermeasures.

Federal Highway Administration logo.
Office of Safety logo: Safe Roads for a Safer Future
Page last modified on October 17, 2017
Safe Roads for a Safer Future - Investment in roadway safety saves lives
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000