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FHWA Highway Safety Programs

6. Case Studies

This section contains descriptions of programs and projects implemented by select local jurisdictions to address roadway departure crashes. These programs illustrate how local practitioners have instituted processes or select countermeasures to address roadway departure crashes on their roadways.

6.1 Low-cost Local Safety Solutions: Douglas County, Georgia10

Douglas County, Georgia developed a County Curve Action Plan as part of the Georgia Department of Transportation's Safety Action Plan Program. This plan has been particularly helpful to the county as it supported funding opportunities through the Georgia Off-System Safety Program.

One of the principal components of their safety action plan, which aligns with the Georgia SHSP, is a focus on roadway departure crashes along curves. Horizontal curves on local and rural roadways represent a major concern in Douglas County, because many of their roads are former wagon trails that were paved over time without addressing the roadway alignment, shoulders, clear zones, and lighting to meet current standards. Consequently, the County experiences a significant number of roadway departure crashes associated with these types of curves.

With a lack of comprehensive data, the County depended on their County Road Department staff, historic knowledge from the sheriff department, and residents to supplement the available data to develop the Curve Action Plan. High-risk locations were identified. A consultant was hired to conduct a qualitative analysis of critical locations and identify countermeasure strategies where appropriate. Improvement strategies included signing and striping modifications as well as center line and edge line raised pavement markers.

There has been a significant reduction in roadway departure crashes since the county began implementing low cost strategies such as warning signs, chevron signs and raised pavement markers along the curves. After installing the double advance warning signs, chevrons alignment signs, and raised pavement markers, a number of crashes continued to occur along some curves. The County took another step by adding the "curve ahead" markings on the pavement, including arrows, developed by Pennsylvania Department of Transportation. The pavement markings have made a tremendous difference as there have been no crashes in the treated locations since the installation.

Keary Lord, Assistant Director
Douglas County DOT
(678) 715-5372

6.2 Engineering and Enforcement Safety Solutions: Contra Costa County and Alameda County, California11

Winding curves, lack of guardrails, and short sight distance in certain areas were creating a difficult environment for motorists utilizing the heavily congested Vasco Road in both Contra Costa and Alameda Counties. The traffic volumes on Vasco Road had more than doubled from 10,000 vehicles per day in 1990 to over 22,000 in 2007, resulting in a high number of collisions. Between 2002 and 2004, 72 crashes occurred along the project corridor, many of them related to roadway departure.

To address the high incidence of roadway departure crashes, a comprehensive, cooperative, and multijurisdictional approach was taken to address speeding and aggressive driving on Vasco Road. As a result, in 2004, the Alameda County Public Works Agency, the Contra Costa County Public Works Agency, City of Brentwood, City of Livermore, the Alameda County Sheriff's Department, and the California Highway Patrol offices in both counties joined with community groups and elected officials in an attempt to reduce crashes along Vasco Road. They introduced a variety of safety measures, including the following:

  • Speed display signs;
  • Community safety signs;
  • Daytime headlight signs;
  • Center line rumble strips;
  • Soft median barrier striping;
  • Center line delineators;
  • Double fine zone; and
  • Coordinated speed enforcement.

These measures have produced extraordinary results. The collaborative traffic engineering, speed enforcement, and funding efforts of both counties have significantly reduced head-on collisions and improved overall roadway departure safety along Vasco Road. The crash rate per million vehicle miles dropped from 0.58 to 0.42. Between 2005 and 2007, there have been just 46 collisions, a 36 percent reduction from previous years.

Paul Keener
Alameda County Public Works Department

6.3 Signing and Marking Improvements: Mendocino County, California12,13,14

The terrain of Mendocino County, a large rural county with more than 1,000 centerline miles of county-maintained roads, is mountainous with a few small valleys. Traffic-related injuries and fatalities in the county are primarily the result of roadway departure crashes.

In the 1990s the Mendocino County Department of Transportation (MCDOT) developed a Road System Traffic Safety Review program to improve signing and markings on the arterial and collector roadways on their system. Each year the team completes a systematic review of one-third of the county roads, identifying potential signing and marking deficiencies, recommending changes based on the current California Department of Transportation (Caltrans) signing and marking guidelines, and implementing the results.

During recurring three-year cycles, all arterials, all collectors, and a number of selected local roadways are reviewed. These annual reviews are funded through the Mendocino Council of Governments (MCOG) with a combination of state and local monies. Early efforts in Mendocino County concentrated on improving signing for curves and eliminating nonstandard signing in order to conform to current Caltrans standards. Funding from the Caltrans Hazard Elimination Safety (HES) Program was used to upgrade approximately one-quarter of the county's signs the first year. Since then, funds to implement the recommendations of the annual reviews have been allocated in the MCDOT budget.

The effectiveness of the Traffic Safety Review project was measured by comparing roadway departure crash data for reviewed roads with data for roads not included in, or influenced by, the reviews. Over two consecutive, three-year cycles, the number of crashes on the reviewed roads fell dramatically by 42.1 percent while on those county-maintained roads not reviewed increased by 26.5 percent. Using cost data provided by the California Department of Transportation, the County calculates that, for an expenditure of $79,300, the project prevented between $12.6 million and $23.7 million in traffic crash losses.

The results speak for themselves. Mendocino County has since expanded the Road Traffic Safety Review program to cover its entire county-maintained road system.

Stephen Ford
Mendocino County Department of Transportation

6.4 Local Road Safety Audits: Cape May County, New Jersey15

The South Jersey Transportation Planning Organization (SJTPO) instituted its Local Road Safety Audit program in 2004 in response to the disproportionate share of roadway departure crashes occurring on rural two-lane roads in the SJTPO region. SJTPO took a data-driven approach to the safety audit program. Audits were first conducted on two Cape May County roads with documented crash histories and significant roadway departure crash potential.

A consultant firm conducted the audits with the assistance of the Cape May County Engineer's office and SJTPO. Of special interest is the interdisciplinary nature of the audit teams, which consisted of county representatives, law enforcement, engineering and public works staff of the affected municipalities, the New Jersey Department of Transportation, the Division of Highway Traffic Safety and the Federal Highway Administration.

The audits have raised awareness among local decision makers by identifying low-cost, quick turn-around safety improvements that are expected to yield immediate safety benefits to address roadway departure crashes. It was one of the first local programs of its kind, utilizing Federal planning funds to systemically identify local road segments of concern, organize a team of independent specialists, engage a consultant team for the audits, and secure Federal funding for the resulting recommended improvements.

Timothy Chelius
South Jersey Transportation Planning Organization

Source: 2005 National Roadway Safety Awards Best Practices

10 Federal Highway Administration, "Noteworthy Practices: Addressing Safety on Locally-Owned and Maintained Roads." (Washington, D.C.: 2010). Available at

11 2009 National Roadway Safety Awards Best Practices. Accessed at

12 The American Traffic Safety Services Association and the National Association of County Engineers, Low-cost Local Road Safety Solutions (Fredericksburg, VA: 2008). Accessed at:

13 Federal Highway Administration and the Roadway Safety Foundation, 2007 National Roadway Safety Awards Best Practices Guidebook (Washington, DC: October 2007). Accessed at:

14 Peaslee, G. "Signs Show the Way to Cost-Effective Rural Safety," Public Roads, January/February 2005. Accessed at:

15 Federal Highway Administration and the Roadway Safety Foundation, 2005 National Roadway Safety Awards Best Practices Guidebook (Washington, DC: 2005). Accessed at