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FHWA Home / Safety / Local and Rural Road / Local and Rural Road Safety Briefing Sheets

Local and Rural Road Safety Briefing Sheets

Unpaved Roads: Safety Needs and Treatments

USDOT Triskelion logo
U.S. Department of Transportation
Federal Highway Administration
Office of Safety Logo: Safe Roads for a Safer Fugure

FHWA-SA-14-094

Downloadable/Printable Version:
[PDF, 478 KB]


Introduction

According to the Federal Highway Administration (FHWA), in 2012 there were 1,357,430 miles of unpaved road in the United States, accounting for almost 35 percent of the more than 4 million miles of roadway in the Nation.1 However, nationally unpaved roads only account for approximately 2 percent of fatalities. Although nationally the percentage of fatalities and serious injuries are low, in some states these roadways account for up to 20 percent of the fatalities.

Local and rural road owners are responsible for a large proportion of these unpaved roads and need information on strategies to enhance the safe operations on these roadways. There are safety strategies that can be employed to improve safety on unpaved roads, and this document describes safety needs and treatments of unpaved roads.

Some unpaved roads have a smooth, wide, well maintained surface with wide shoulders. Others have narrow or no shoulders and loose, rutted, or washboard surfaces where vehicles may slide out of control due to a severely raveled surface. Unfortunately these problems are often the worst where vehicles turn and brake, such as curves and intersections where vehicle control is most critical. In addition, poor quality aggregate can lead to excessive dust, which can obscure a driver's view of the road and oncoming traffic.2

An abrupt change from a paved to an unpaved surface creates a risk of skidding and losing control of the vehicle. Advance warning about upcoming unpaved conditions for unfamiliar drivers is critical. As long as the roadway is consistent, drivers soon adjust their behavior to match the limitations of the road; however, because of low traffic volumes and minimal law enforcement presence on many unpaved roads, drivers may travel at unsafe speeds. When inconsistencies are present, the driver may be taken by surprise, which can result in an increase in crash risk.

Pie chart depicts the percent of paved roads (65 percent) and unpaved roads (35 percent) in the Unted States in 2012.

In addition to characteristics affecting driving behavior, there are a number of additional physical features of unpaved roads that can impact safety including:3

Safety Strategies for Unpaved Roads

Owners of unpaved roads may apply any number of strategies to address the safety problems identified on unpaved roads. These include approaches that are similar to actions applied on paved roads as well as actions that address safety problems due to road surface deficiencies.4

An unpaved rural roadway running over a narrow, single-lane bridge with guard rails on either side.

Conduct a Review of Clear Zone

Improve Sight Distances

Install Delineators and Chevrons

Rural unpaved road with a chevron to the right of the travel way.

Step Up Speed Enforcement

Maintain the Road Surface5

Conclusions

Unpaved local and rural roads represent a significant share of the public roadway system in some states. Road owners should understand the types of safety challenges presented by these facilities as well as the types of safety treatments available to address these challenges.

A rural roadway curves into the foothills of a mountainous region with a river running through a basin in the distance.

Resources

Additional information can be found in the following:

Bustad, Jacob, Good Gravel Roads, Kansas LTAP Fact Sheet.

Field Guide for Unpaved Rural Roads developed by Wyoming Technology Transfer Center, March 1997 and updated by Kansas Local Technical Assistance Program, July 2004.

Huntington, G. "Road Geometry, Surface Materials Are Key to Safety on Gravel Roads," Safety Compass Newsletter, 6:2 (6) Fall 2012.

Huntington, G. and Ksaibati, K., Gravel Roads Management: Implementation Guide, Volume 2 (University of Wyoming: October 2010).

Huntington, G. and Ksaibati, K. Gravel Roads Management, Volume 1 (University of Wyoming: October 2010).

MacDonald, T. and Sperry, R., Evaluation of Mitigation for Safety Concerns on Low-Volume, Unpaved Rural Roads (Iowa State University Institute for Transportation: May 2013).

South Dakota Local Transportation Assistance Program (SD LTAP), Gravel Roads Maintenance and Design Manual (Washington, DC: November 2000).



1 Federal Highway Administration, "Highway Statistics 2012," (Washington, DC: 2012).

2 Huntington, G. "Road Geometry, Surface Materials Are Key to Safety on Gravel Roads," Safety Compass Newsletter, 6:2 (6) Fall 2012.

3 FHWA and NHI, Guide to Safety Features for Local Roads and Streets, 1992

4 MacDonald, T. and Sperry, R. Evaluation of Mitigation for Safety Concerns on Low-Volume, Unpaved Rural Roads. Iowa State University Institute for Transportation: Ames, IA. May 2013.

5 Huntington, George. Safety Compass Newsletter. Federal Highway Administration, 6:2 (6) Fall 2012.

Page last modified on June 2, 2016
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