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Publication Number:  FHWA-HRT-21-002    Date:  Winter 2021
Publication Number: FHWA-HRT-21-002
Issue No: Vol. 84 No. 4
Date: Winter 2021

 

Reducing Rural Roadway Departures: Moving FoRRRwD, Part II

by Cathy Satterfield and Richard B. Albin

FHWA's Every Day Counts initiative is taking a comprehensive approach to saving lives on rural roads.

Each year in the United States, nearly 12,000 people die when their car leaves its travel lane on a rural road. That is 30 people today, and every day.

A rural roadway curve in Franklin County, Ohio. © Franklin County, OH.
About one-third of the Nation's annual roadway deaths occur on rural roads. Implementing proven countermeasures and developing safety action plans can help local agencies address the problem.

The Federal Highway Administration is working with State departments of transportation, Local Technical Assistance Program centers, and local agencies across the country to combat this issue. Under the Every Day Counts initiative called Focus on Reducing Rural Roadway Departures (FoRRRwD), the team is promoting further use of proven strategies to reduce rural roadway departures. Many agencies are using these strategies and seeing positive results. The efforts of these agencies are getting more people home safely.

A Far-Reaching Problem Requires A Comprehensive Approach

The FoRRRwD approach is based on four pillars. The first article in this series (see "Moving FoRRRwD: Focus on Reducing Rural Roadway Departures" in the Autumn 2020 issue of Public Roads) focused on the scope of the problem and the first two pillars–all public roads and the implementation of a systemic safety approach. This article focuses on the other two pillars–the countermeasures recognized to reduce rural roadway departures and the development and implementation of safety action plans.

Proven Countermeasures

There are many cost-effective countermeasures shown to reduce rural roadway departures. When properly applied, they can significantly reduce serious and fatal crashes.

Although rural roads are extremely diverse, from multilane highways to gravel roads, there are countermeasures demonstrated to fit most situations. For example, edge line markings are effective at reducing roadway departures, but they cannot be installed on gravel or dirt roads. However, delineators can be used instead on these roads and accomplish a similar goal. Other treatments are more complex, but any agency can find some method to improve their roadways. If improving entire corridors is not practical, focusing on curves might be appropriate, since 42 percent of rural roadway departure fatalities occur at horizontal curves. The FHWA guide Low-Cost Treatments for Horizontal Curve Safety 2016 (FHWA-SA-15-084) provides information on the application and benefits of many countermeasures.

The proven countermeasures are organized around three objectives for reducing rural roadway departure deaths and serious injury crashes. In priority order, these are: (1) Keep vehicles in their lane, (2) Reduce potential for crashes when vehicles leave their lane, and (3) Minimize severity if a crash occurs. There are specific countermeasures that apply to each objective (https://safety.fhwa.dot.gov/FoRRRwD/countermeasures.cfm).

Keep Vehicles in Their Lane

The primary objective is to prevent drivers from leaving their travel lane. Another term for roadway departure is lane departure, which also includes crossing the center line. Once a driver departs the lane onto the roadside or across the center line into oncoming traffic, the likelihood of a severe crash rises dramatically.

Chevron curve warning signs along a curved road segment, shown during the day. Source: FHWA.
Chevron curve warning signs glow in the light of a vehicle's headlights at night. Source: FHWA.
Graphic retroreflective signs like these curve chevrons provide improved nighttime visibility.

Signs and Markings

In general, pavement markings, signage, and other delineators are used to provide better visibility of the lane or roadway edges, particularly where the alignment changes. This delineation is critical in nighttime conditions where other cues are not available. Basic signing and use of center and edge lines are the first steps to providing more visible roadways. These countermeasures have been shown to be very effective. For instance, chevron signs on horizontal curves can reduce nighttime crashes by up to 25 percent.

Enhanced delineation may be useful where risk factors indicate it will improve driver perception. Potential countermeasures included in this strategy are wider center and edge line markings; post-mounted delineators; signs that are larger, more retroreflective, or fluorescent; and dynamic advance curve warning signs and sequentially flashing chevron signs.

A still screen capture of the title screen of FHWA's video, "Rumble Strips: The Sweet Sound of Safety." Source: FHWA.
FHWA produced a short video about rumble strips. It is available on the agency's official YouTube channel at www.youtube.com/watch?v=2V5-M4-O70E&feature=youtu.be.

Rumble Strips

Rumble strips are another very effective countermeasure for keeping vehicles in their lane. On two-lane rural roads, centerline rumble strips have been shown to reduce opposite direction fatal and injury crashes by 45 percent, and shoulder or edge rumble strips reduce single vehicle run-off-road fatal and injury crashes by 36 percent.

Alternative designs and applications have been developed to address issues related to bicycle accommodation and noise. Creating bicycle gaps and placing rumble strips on the edge line may better enable bicyclists to use the shoulder. Sinusoidal rumble strips, designed with an oscillating sine wave pattern to reduce noise outside of the vehicle, show promise to combat noise concerns (see "Did You Hear That?" in the January/February 2017 issue of Public Roads). Multiple States are trying these, so data should soon be available to assess if sinusoidal rumble strips provide the same level of crash reduction as conventional rumbles.

Many agencies have systematic criteria for installing center and edge rumble strips over a portion of the system. A systemic approach may be better, especially for agencies just beginning to consider rumble strips. (For more information on systematic vs. systemic approaches, see "Moving FoRRRwD: Focus on Reducing Rural Roadway Departures" in the Autumn 2020 issue of Public Roads). Installing them on corridors of highest risk for roadway departure fatal and injury crashes provides the opportunity to achieve the highest number of crash reductions for each dollar spent.

High-Friction Surface Treatments (HFST)

HFST greatly increases friction on roadway surfaces. This is particularly important in locations such as curves, where friction is critical and tends to deteriorate prematurely. HFST is a very durable treatment at such locations, and reduces the need to implement higher cost solutions, such as curve flattening, increased superelevation, or reconstruction. It may also eliminate the need for additional rights-of-way.

This countermeasure has been shown to reduce wet weather curve crashes by 83 percent and reduce overall curve-related crashes by 57 percent. It has also been shown to be highly cost-effective, with a benefit-cost ratio of 6:1. Like other countermeasures, project locations can be bundled to increase cost-effectiveness.

For example, the Kentucky Transportation Cabinet installed HFST in 15 short curves on the minor road system and achieved a more than 70-percent reduction in overall crashes. At several sites, there were zero crashes in the 5-years-after period.

Reduce Potential for Crashes

While keeping vehicles on the roadway is the first priority, there are several proven strategies for reducing the likelihood of a crash for those vehicles that do leave the roadway.

SafetyEdgeSM

The SafetyEdge technology shapes the edge of the pavement at approximately 30 degrees from the pavement cross slope during the paving process. That angle eliminates the potential for vertical dropoff at the edge of the pavement and enables drivers to recover and re-enter their lane with less potential to lose control. Because the SafetyEdge is installed during the paving process, there is minimal effect on asphalt paving cost, and it can improve pavement durability by preventing edge raveling. Evaluations of safety effectiveness have shown a 21-percent reduction in run-off-road crashes and a 19-percent reduction in head-on collisions. This results in a very high benefit-cost ratio. SafetyEdge can also be installed on concrete pavements when they are constructed, although the cost is more significant than on asphalt projects.

A rural road with a High-Friction Surface Treatment. Source: FHWA.
HFST has been shown to reduce wet weather curve crashes by 83 percent.

Enhanced Roadside Design

Improving roadside design, especially at curves, includes adding or widening shoulders, flattening slopes and improving ditch design, and providing and maintaining adequate clear zones.

Shoulder widening creates additional space for a vehicle to recover and can be done in conjunction with installing rumble strips and adding SafetyEdge. Slope flattening reduces the steepness of the roadside and provides more stability, decreasing the potential for rollover, and increasing the opportunity for drivers to recover.

Providing a wider roadside clear zone often means removing rigid objects such as trees and utility poles. This can be more expensive than other countermeasures, but focusing these improvements to the outside of specific, higher risk curves systemically prioritizes higher risk locations. Safety effectiveness evaluations show a 22-percent crash reduction by increasing the distance to trees by 3 feet (0.9 meters), and up to 71-percent reduction when increased by 15 feet (4.6 meters).

A rural road with no shoulder. Source: FHWA.
A rural road with a shoulder and rumble strips. Source: FHWA.
Rumble strips are effective for keeping vehicles in their lanes. Widening shoulders provides space for vehicle recovery and can also provide room for rumble strips.

Minimize Severity if a Crash Occurs

Sometimes crashes happen despite the best efforts of agencies to keep drivers in their travel lane or provide for a safe recovery. Where signs or poles are needed or where roadsides cannot practically be improved, hardware exists to minimize the severity of crashes that may occur. Two proven strategies for minimizing severity are installing breakaway and energy-absorbing designs on posts and poles and installing roadside and median barriers.

While installing a barrier can lead to an increase in total crashes because of reported property damage, it is important to remember that the goal is to reduce fatal and serious injury crashes. A sideswipe crash into a barrier will damage the vehicle, but is much less prone to cause serious injury to the people in the vehicle than a collision with a tree or a rollover on a steep slope.

The entire goal of the FoRRRwD effort is to save the people behind the crash numbers.

Choose the Options That Work for You

Severe rural roadway departure crashes can be reduced or eliminated in high-risk locations. A quote attributed to President Theodore Roosevelt applies: "Do what you can, with what you have, where you are." Agencies should use the proven countermeasures that best fit their situations and budgets–but leaving them on the shelf should not be an option.

The three objectives of keeping vehicles in their lane, reducing potential for crashes, and minimizing crash severity can also be combined to provide redundancy. Providing curve signing to keep vehicles on the road will reduce crashes. However, combining them with the removal of fixed objects or providing a barrier will compound the reduction. This redundancy will be critical to achieve the vision of zero fatalities. "Think of the countermeasures as a menu of options," says Cornell Robertson, the county engineer for Franklin County, OH. "Each has a specific focus, but they can be used together for maximum effect."

Installation of multiple countermeasures or multiple project locations can also be bundled together in a single contract to increase cost-effectiveness. Bundling can happen within a single agency or across a region and involve several agencies. This provides an opportunity to get more done within a small budget.

Safety Action Plans

The first three FoRRRwD pillars–considering all public roads, using a systemic approach, and implementing proven countermeasures–provide the tools necessary to reduce roadway departures. Using them to develop an action plan is an effective way to prioritize and communicate an agency's safety needs.

An infographic illustrating the process for developing a local road safety plan, moving through the steps of identifying stakeholders, using safety data, choosing proven solutions, and implementing solutions. Source: FHWA.
Agencies can tailor their local road safety plans to meet their specific issues and needs.

Safety action plans, such as statewide roadway departure action plans or local road safety plans, provide a framework to identify, analyze, and prioritize roadway safety improvements. The process for developing these plans is flexible and can be easily tailored to specific agency issues and needs.

Safety action plans have many benefits. A plan enhances the awareness of stakeholders about the need to tackle rural roadway departure crashes. In developing the plan, agencies establish partnerships that can be further leveraged for implementation.

Plans can also be a communication tool to explain investment decisions to staff, leadership, and the public. By documenting data analysis, recommendations, and implementation strategies, the plan explains the project prioritization–why particular projects need to be done at certain locations and in what order. In addition, a plan may help an agency compete for additional funding in some instances and provides a yardstick to measure the agency's efforts.

"Our safety plan has been a catalyst to bring all our stakeholders together with one vision," says Craig Parks, the former county engineer for Boone County, IN. "We included law enforcement, public health, and elected officials. When we all looked at the plan together, they really understood that we were making data-driven decisions, and all of us had a part to play in getting people home safely each day."

Another benefit of having an action plan is that it can survive staff turnover. As people move in and out of an agency, the plan provides a consistent path to guide those who were not there when it was developed.

Plans are also scalable, and can be customized to an agency's needs and priorities. They are not one size fits all. Some agencies' plans are just a few pages. Others comprise more than 100 pages. The plan depends on what the agency's individual needs are and what it is trying to accomplish.

Implementation Is Required

Safety action plans are proven to work if they are implemented. It is critical that agencies commit to seeing the improvements identified in their plans become a reality–the reason someone makes it home safely today. To get the most out of a safety action plan, agencies should consider aligning the plan with existing priorities, engaging maintenance staff, including implementation strategies, and marketing.

Align the plan with existing priorities. Every State has a strategic highway safety plan (SHSP) that outlines safety issues to be addressed statewide. As much as possible, match safety projects in the safety action plan with SHSP priorities. This can build support for the plan. However, these priorities may need to be adjusted based on an agency's own data.

Engage maintenance staff. Many times, operations and maintenance staff form the front line of local agencies. Include maintenance staff in the development of local road safety plans. They can then be proactive in installing low-cost countermeasures identified from the plan during their routine work.

Include implementation strategies. Along with the locations where countermeasures will be effective, include strategies to cost-effectively implement them in the plan. Strategies might include maintenance staff performing the work, bundling projects with similar treatments into a single contract, or installing countermeasures during other planned work in those corridors.

Market the plan. Be intentional with marketing and outreach. Marketing safety is especially important when developing a local road safety plan. Know the stakeholders and target the message to the specific audience. Add it to the agenda in formal meetings, but also bring it up in conversation. Talk about the benefits consistently to bring as many people as possible into the process, across diverse functional areas and even other agencies. Consistent marketing builds buy-in.

Help Is Available

Through the FoRRRwD effort, agencies looking to develop or implement safety action plans can request technical assistance on any aspect of plan development. Examples of technical assistance provided include:

  • Helping to form a stakeholder group.
  • Conducting data analysis for agencies.
  • Providing or customizing tools for agencies to analyze their own data.
  • Identifying potential countermeasures based on risk factors, target crash types, and target facility types from the analysis.
  • Developing timelines and goals for implementation.
  • Evaluating the effectiveness of countermeasures already installed.

FHWA has launched a new Local Road Safety Plan Do-it-Yourself website at https://safety.fhwa.dot.gov/LRSPDIY to help local agencies. The site includes video content to explain and demonstrate the steps of the planning process and offers dozens of tips, tutorials, resources, and examples. The site houses previously developed infographics, templates, videos, presentations, webinars, training modules, and tools, as well as featured interviews with State and local agencies that have been engaged in developing local road safety plans across the country. For more information, see "Internet Watch" on page 45 in this issue.

Screen capture of FHWA's Local Road Safety Plan Do-It-Yourself website. Source: FHWA.
FHWA's new website helps agencies develop a local road safety plan.

Save the People Behind the Numbers

"Rural roadway departure crashes represent a huge challenge on the Nation's roadways," says Michael Griffith, director of FHWA's Office of Safety Technologies. "There is, however, a clear path to reducing them and help is available from FHWA."

FHWA urges States to consider all public roads, use a systemic approach, implement proven countermeasures, and develop a safety action plan. These four pillars are proven to work.

Thirty people will die today from rural roadway departure crashes. Some of them could be your neighbors or loved ones. Let's save the people behind the numbers!


Cathy Satterfield, P.E., works on roadway departure and visibility programs in FHWA's Office of Safety. She has a B.S.C.E from the University of Minnesota.

Richard B. Albin, P.E., is with the FHWA Resource Center and specializes in reducing roadway departure crashes. He has a B.S.C.E. from the University of Wyoming.

For more information, see www.safety.fhwa.dot.gov/forrrwd or contact Cathy Satterfield, cathy.satterfield@dot.gov, or Dick Albin, dick.albin@dot.gov.

 

 

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