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Publication Number:  FHWA-HRT-21-001    Date:  Autumn 2020
Publication Number: FHWA-HRT-21-001
Issue No: Vol. 84 No. 3
Date: Autumn 2020

 

Moving FoRRRwD: Focus on Reducing Rural Roadway Departures

by Cathy Satterfield and Richard B. Albin

FHWA is partnering with State and local agencies to save lives on rural roads.

A rural highway.
Rumble strips have been installed for as little as 10 cents per linear foot—a low-cost countermeasure that can be deployed systemically.

Each year in the United States, nearly 12,000 people die in roadway departure crashes on rural roads. That is more than 30 people today, and every day.

It is easy to overlook how serious a problem this is because those deadly crashes happen in scattered locations across vast rural roadway networks. Rural roadway departure crashes (also called lane departures) do not cause massive traffic jams. There are no multicar pileups that make the news. They happen one here, one there, like a dripping faucet. Combined, however, those far-flung crashes account for roughly 30 percent of the Nation's annual roadway deaths. It is truly a national problem.

Is there a way to save the people behind those numbers? Can agencies, with increasingly limited resources, hope to reduce rural roadway departures on their systems? The answer to both questions is yes, but it is a formidable challenge.

The Federal Highway Administration is working with State departments of transportation, Local Technical Assistance Program (LTAP) centers, local agencies, and Tribal and Federal land management agencies across the country to combat this issue under the Every Day Counts initiative called Focus on Reducing Rural Roadway Departures (FoRRRwD).

The FoRRRwD team is promoting further use of proven strategies to reduce rural roadway departures. Many agencies are already implementing these strategies and are seeing positive results. The efforts of these agencies are getting people home safely who may have otherwise died.

"The scale of the rural roadway departure problem is sometimes hard to grasp because it happens largely in the background," says Matthew Enders, the technical services manager for the Washington State DOT. "Once you see it, though, it is obvious that we have to do something. We are passionate about helping agencies solve this problem."

FoRRRwD is based on four pillars: consideration of all public roads, a systemic safety approach, proven countermeasures, and safety action plans. This article focuses on two of the pillars‐addressing the problem on all public roads and use of a systemic approach. A companion article in an upcoming issue of Public Roads will focus on proven rural roadway departure countermeasures and development of safety action plans.

Improving Safety On All Public Roads

Rural roadway departure crashes are a major problem on all public roads. Fifty to 60 percent of fatalities happen on roads typically maintained by State DOTs. That leaves more than 40 percent of rural roadway departure fatalities scattered across the 79 percent of the rural road mileage under the jurisdiction of the more than 3,000 counties, 16,000 towns and townships, or other jurisdictions across the United States.

Any national strategy to reduce rural roadway departure deaths that does not address these non-State roads is only working on half the problem. This is a crucial point for three reasons. First, most local agencies have insufficient resources for dedicated roadway safety staff. That means it is difficult for them to learn or apply the latest safety analysis techniques or to collect the data necessary to support the analysis. Second, many local agencies have little or no crash data to use. Third, most local agencies lack sufficient funding to mount a concerted effort on reducing rural roadway departure crashes. Some U.S. counties are larger landwise than some U.S. States and have tens of thousands of lane miles to monitor. Because rural roadway departure locations are scattered and random, many local agencies may have difficulty getting a handle on the problem on their own.

A graphic showing the four pillars of the Focus on Reducing Rural Roadway Departures (FoRRRwD) program: proven countermeasures, systemic approach, safety action plans, and all public roads.

Partnerships Create Solutions

The national problem of deaths on rural roadways requires going beyond the State network of roads. It demands local partnerships to address the problem on all public roads. Several State DOTs, metropolitan planning organizations (MPOs), and regional planning commissions have stepped in to help their local counterparts. These agencies are making Federal and State funds available to local agencies based on the proportion of severe crashes happening on local systems. They are also making it easier for local agencies to apply for funding. And because data are key to this process, DOTs, MPOs, and regional planning commissions are helping local agencies with data acquisition, compilation, and analysis.

"Most drivers don't know if they are on a State or local road," says John Michael Walker, P.E., the State traffic and safety operations engineer for the Alabama DOT. "Those peoples' lives depend on the safety of all public roads, and that means all agencies working together."

North Dakota is another State assisting local agencies. They asked, "How do you to get to zero fatalities if you don't address the local road system?" According to Bryon Fuchs, assistant local government engineer with the North Dakota DOT, the State splits Federal safety funds fifty-fifty with local agencies, because that is the proportion of fatalities on each system.

Washington State DOT splits its Federal safety funds between the State, counties, and cities based on the proportion of fatal and serious injuries on each, which results in 70 percent going to local agencies. Washington's LTAP Center is one of several that have jumped in to assist local agencies with data analysis.

A graphic titled 'Rural Roadway Departure Crashes by the Numbers,' with three pie charts. The first chart shows rural roadway departure deaths, with three segments: rural, with 11,674 deaths, or 34 percent; urban, with almost half, and other rural. The second pie chart shows rural roadway departure crash types, with four segments: 3,354 head-on crashes, or 28 percent; 3,609 rollover crashes, or 30 percent; 2,312 crashes into trees, or 19 percent; and 23 percent other crashes. The third pie chart is labelled 'all roadways are affected' and shows types of roadways on local networks and state networks. Of the local networks, 23 percent are major collector roads, 6 percent are minor collector roads, and 16 percent are other local roads. Of the state roads, 10 percent are interstates, 26 percent are other principal arterial roads, and 19 percent are minor arterial roads.

The Louisiana Department of Transportation and Development (Louisiana DOTD) recently collected spatial coordinates of all public roads in Louisiana and loaded them into the agency's geographic information system (GIS). The effort resulted in a complete roadway basemap that Louisiana DOTD shares with local agencies.

The Acadiana Planning Commission (APC), an MPO in Louisiana, used the Louisiana DOTD GIS to inventory the roadways in their own jurisdiction. Together with Louisiana DOTD, the APC can now analyze safety using GIS data to integrate crash, roadway, and traffic volume data. The data analysis is invaluable for making informed safety investments and will provide justification to pursue funding.

A curved rural roadway.
A typical rural local road may not have edge lines, shoulders, or signing. In some cases, the roads may not be paved.

"The data collection and the tools developed by DOTD and the APC have been helpful in identifying locations where motorists have lost control of their vehicle and run off of the road on Acadia Parish's local roadways," says Michael Schexnider, the road manager for Acadia Parish. "Thanks to this data collection, we were able to plan and program a systemic roadway departure project to address curves on 12 roadways to reduce crashes in Acadia Parish."

The APC also works with Louisiana DOTD and local agencies to perform network screening and countermeasure selection. They help with asset management, roadway inventory updates, and a variety of other functions that may be beyond the resources of their local and parish-level partners.

These are the types of partnerships that are critical to address the crashes beyond the State system.

A map of roadways in part of Ohio shows the scattered nature of crashes on rural roadways.
Hot spot analysis does not work well for rural roads, which tend to have widely scattered crash sites, as shown on this map of crashes on Ohio roadways for 2014 to 2018.

Three Approaches to Safety

There are three approaches that most transportation agencies use to identify safety projects: "hot spot" analysis, systematic analysis, and systemic analysis. Some work better than others for certain types of crashes, and some work better for certain countermeasures. Ideally, they should be used together to be most effective.

  • Traditional Hot Spot Analysis

    The hot spot approach uses historic crash data to identify sites with the most significant crash performance measures (such as crash frequency and crash rate). Sites with the highest numbers are deemed hot spots. Agencies identify hot spots, analyze the problem, and then install countermeasures to mitigate crashes.

  • Systematic Approach

    With this approach, agencies install a countermeasure—rumble strips or SafetyEdgeSM, for instance—over an entire portion of their system meeting certain criteria, regardless of the number of crashes at any one location.

  • Systemic Approach

    Systemic analysis (not to be confused with systematic) uses roadway geometrics, traffic characteristics, and maintenance information along with crash data to identify risk factors, then uses those risk factors to identify locations at highest risk of future crashes. Low-cost countermeasures are installed at targeted, high-risk locations across the system, even if there has not been a crash.

The Trouble with Hot Spots

While it is important that States review crash data to identify and address locations with concentrations of crashes (hot spots), this approach is not suited to the nature of rural roadway networks. Hot spots by definition are clusters of crashes at a single location. Hot spots may occur on roadways with high traffic volume and in urban areas, but are almost nonexistent on rural roads.

While the types of roadway departure crashes are fairly predictable (run-off-road or head-on collisions in horizontal curves, for example), specific crash locations are random from year to year, and they rarely happen at the same location multiple times. Because hot spot analysis depends on groupings of crashes at specific locations, it does not accurately reflect how rural roadway departures occur. Even if an agency finds a hot spot and mitigates it, doing so will not solve the larger problem because most crash locations will shift around the network each year. In addition, hot spot solutions are often expensive, such as rebuilding a curve or widening shoulders, which may involve purchasing right-of-way.

The other weakness of hot spot analysis is that it is reactive. It is based solely on past crashes, which leaves agencies waiting for a tragedy before anything can be done.

A close up of the equipment used to apply an angled edge to a newly paved roadway.
SafetyEdgeSM is a very low-cost countermeasure applied during the paving process. The gentle angle enables cars to return to the roadway safely following a departure.

Is Systematic Feasible?

The systematic approach has advantages over hot spot analysis as it can be done proactively. For example, an agency can set criteria that mandate installation of SafetyEdgeSM any time it paves a road without a curb, no matter the location. Adding safety treatments during other planned projects like widening shoulders when overlaying an existing narrow road can be cost-effective.

A man measures the angle of the edge a newly paved roadway.
An FHWA engineer measures the angle of the SafetyEdgeSM installation during a new paving project on a rural road.

However, the systematic approach does not apply countermeasures where they are most needed. It does enable safety improvements to be added, but other priorities often determine the order in which projects are completed, rather than where the highest risks can be reduced. Therefore, safety improvement installations across the network are often delayed. It can also be costly. Few agencies, especially local ones, have the money or staff to install and maintain every safety feature on every mile of road, even when limiting the use of countermeasures based on standard criteria.

Another key concern with this approach is that systematic criteria can be exclusionary. For example, agencies often exclude the use of rumble strips on narrow shoulders because of bicyclist concerns. However, roads with narrow shoulders tend to have higher risk of serious roadway departure crashes and would be a good location for rumble strips. Widening shoulders is beneficial to both bicyclists and to reduce roadway departures, but can be cost-prohibitive and in conflict with environmental goals. As a result, it is possible to miss high-risk locations when applying systematic policies.

It is therefore not effective to use only the systematic approach to solve the roadway departure crash problem.

A Systemic Approach Works For Health and Roadways

The systemic approach has benefits over both the hot spot and the systematic approach. It is proactive, targeted, and more cost-effective than the other methods. It looks not only at where crashes have occurred in the past, but the factors at those locations that likely contributed to the crashes. It then uses those identified risk factors to prioritize potential countermeasures and where they should be applied first to do the most good.

Systemic analysis sees a roadway system like a doctor does the human body. When you go for a physical, the doctor starts with data specific to you, such as your weight and blood pressure, then moves on to your medical history. Does anyone in your family have a heart condition? Diabetes? What about high cholesterol? The doctor then asks about personal habits. Are you a smoker? How often do you exercise?

Physicians understand that the human body is a system, and studies on large groups of people over long periods of time give them information on how various factors contribute to disease. Therefore, the doctor assesses the body system, looking for risk factors that may indicate future disease—enabling a proactive approach. Someone with multiple risk factors for heart disease, for example, can be prescribed treatment to fend off a heart attack. It would be unethical to wait until the patient had a heart event to recommend action.

Systemic analysis assesses a roadway system like the doctor. It starts with network crash data: Where have crashes happened? Compiling those data provides context to identify commonalities that exist in the roadway or traffic features that may have contributed to the crashes. If an agency does not have data of its own, data from similar roads elsewhere in the region, State, or nation may help determine appropriate risk factors. This is where systemic analysis departs from the hot spot approach. Instead of only mitigating locations of past crashes, the systemic approach also treats other locations that have similar features to typical crash locations.

Suppose a local agency finds that, out of 10 rural curves with injury crashes, 8 of those curves had a radius between 500 and 1,000 feet (150 to 300 meters). Now suppose six of those curves had no edge lines.

A rural roadway that appears to go straight.
The presence of a visual trap (where it appears the road goes straight when it actually curves) is a qualitative risk factor that an agency might use in its systemic analysis.

Just like the doctor knows high blood pressure and lack of exercise are risk factors for heart disease, it would be logical for the agency to conclude that other curves with a radius between 500 and 1,000 feet (150 to 300 meters) and no edge lines are at higher risk of rural roadway departures, even if one has not happened yet. It would also be logical to install edge lines and perhaps other treatments, such as chevrons, at all curves with those same risk factors, across the entire system.

The systemic approach lets agencies target their investments to the locations at highest risk of severe roadway departures. It uses past data to assess risk of future crashes and prevent them. It lets safety set the agenda.

"It really opened up my eyes, and my staff's eyes, to what our problems are across our system," says Thomas Mattson, the director of public works for Humboldt County, CA. "Systemic lets you step back and say, 'A problem can occur anywhere on my system, what are the probabilities and what are my best methods of stopping that kind of problem across the entire system?'"

That is the breakthrough of systemic analysis and why it is one of the pillars of the FoRRRwD approach. Agencies can identify sites for safety improvement based on focus crash types (such as run-off-road), facility type (such as two-lane rural roads), and risk factors (such as tight curves).

The Benefits of the Systemic Approach

A key benefit to the systemic approach is that agencies can use the data they have now—even minimal data. This addresses the dearth of data for most local agencies. By looking at traffic and roadway features, a systemic approach enables agencies to use information gleaned from studies in other similar roadway environments. More benefits are likely to be achieved with higher-quality data, but not having some data does not exclude an agency from being able to apply this approach.

"Everybody has some data. Use what you have to start," Mattson says. "If you have to get more data, go for it, but don't not do anything just because you don't think you have enough data."

An additional benefit to the systemic approach is that many of the countermeasures used to improve high-risk locations are low-cost. Agencies also do not have to wait for large capital projects to install some of the countermeasures. For instance, trimming vegetation and installing curve warning signs can be performed during routine maintenance.

"The systemic approach enables widespread, proactive deployment of low-cost countermeasures at the locations most in need, based on data," says Jerry Roche, manager of the Data-Driven Safety Analysis Program in FHWA's Office of Safety. "That surgical mindset is getting results."

A road with rumble strips on the edges.
Rumble strips have been installed for as little as 10 cents per linear foot—a low-cost countermeasure that can be deployed systemically.

We Can Do This

It is possible to reduce rural roadway departure crashes, but it will take a disciplined, national effort from agencies at all levels. These deadly crashes are a problem on all public roads, so they must all be considered. Partnerships between States, local agencies, LTAP centers, Tribes, and other agencies are critical to implement improvements to reduce these crashes. Agencies should also address their roads systemically, focusing on risk instead of crash history alone. An upcoming article in Public Roads will describe cost-effective roadway departure countermeasures and explain the value of developing safety action plans.

Thirty people will die today from rural roadway departure crashes. Let's save the people behind the numbers.


Cathy Satterfield, P.E., is a roadway safety engineer in FHWA's Office of Safety, leading the roadway departure and visibility programs. She has a B.S. in civil engineering from the University of Minnesota.

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

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