FHWA continues its increasingly important role of helping meet the needs of a growing demographic. Check out the Handbook for Designing Roadways for the Aging Population.

How many U.S. drivers are getting older, becoming seniors, or aging into their “golden years”? Whatever is the best phrase, the U.S. population is definitely shifting. In 2012, 43.1 million people were age 65 or older. By 2030, according to the Administration on Aging, which is part of the U.S. Department of Health and Human Services, approximately 72.1 million will fit in that age category. Transportation professionals take note: By then, approximately one-fifth of the population in the United States will be older adults.

Although the number of fatalities and the fatality rate, both overall and among aging road users, has declined in recent years, people age 65 or older are still involved in a disproportionate share of fatal crashes compared with the population as a whole. People age 65 or older currently make up only about 13 percent of the Nation’s population, but the National Highway Traffic Safety Administration’s analysis of driver and crash data indicates that they represent approximately 16 percent of drivers, 16 percent of driver fatalities, and 20 percent of pedestrian fatalities.

With that in mind, the transportation community needs to consider the consequences of these changing demographics. This growing group of drivers, pedestrians, and other road users are experiencing declining vision; slowed decisionmaking and reaction times; exaggerated difficulty when dividing attention between traffic demands and other important sources of information; and reductions in strength, flexibility, and general fitness. The Federal Highway Administration ran a series of articles in Public Roads in 2006 and 2007 that focused on these declining driving abilities.

In 2012, recognizing the need to focus on the aging road user, Congress included the Special Rule for Older Drivers and Pedestrians in the Moving Ahead for Progress in the 21st Century Act (MAP-21). States now are required to consider countermeasures if their rates of fatalities and injuries for older drivers or pedestrians show an increase during the most recent 2-year period.

In response to the surge in aging road users, FHWA released the Handbook for Designing Road-ways for the Aging Population (FHWA-SA-14-015) in June 2014.

“Communities across the Nation recognize the transportation challenges facing older adults and are looking for methods to keep them safely on the move,” says FHWA Associate Administrator for Safety Tony Furst. “Our new Handbook for Designing Roadways for the Aging Population is an excellent resource that gives States and localities detailed, proven practices that can be implemented to meet these challenges and improve the transportation system for all road users.”

History of the Handbook

More than 17 years ago, FHWA published the Older Driver Highway Design Handbook (FHWA-RD-97-135). This 1998 publication provided highway designers and engineers with the first source of practical information linking age-related declines in functional capabilities to enhanced design, operational, and traffic engineering treatments, keyed to specific roadway features. Experience with these enhanced treatments, including extensive feedback from local- and State-level practitioners, led to the release of the Highway Design Handbook for Older Drivers and Pedestrians (FHWA-RD-01-103) in 2001.

Now, FHWA has released a third version of this resource under the new title Handbook for Designing Roadways for the Aging Population. This latest version incorporates new research, expands the range of applications covered by the previous handbook, and introduces format changes that bring the guide into the digital age. Those changes include a Web-based version to facilitate access and use by engineering professionals who are reviewing and selecting Handbook recommendations to enhance safety on their community’s or State’s streets and highways.

Part I: Treatments

The 2014 Handbook is composed of two parts. The first presents recommendations for treatments and countermeasures that address specific areas of concern for aging road users. The second part presents the supporting evidence, rationale, and previous research results for each treatment. Four supplemental appendices include technical notes, photograph and image credits, a glossary, and an extensive list of references.

The treatments in the Handbook focus on five categories of roadway features, each containing a number of specific design elements for which guidance is provided. The five categories are as follows:

1. Intersections encompass a majority of the recommendations because numerous studies show that intersections are the most problematic areas with respect to crash frequency and severity involving aging drivers. Intersections also involve the greatest exposure to risk for pedestrians.
    
2. Interchanges are addressed with a focus on opportunities to improve difficulties with lane changing (merging/weaving) and wrong-way driving maneuvers.
    
3. Roadway segments place emphasis on horizontal curves (delineation) and provisions for passing zones.
    
4. Construction work zones represent opportunities to enhance path delineation and advance notice of road work. These treatments are warranted due to heightened tracking (steering) demands that may increase a driver’s workload along with an increased potential for unexpected events that require a rapid response.
    
5. Highway-rail grade crossings are the final category. Although conflicts are rare, they can be unexpected and severe. Problems of detection (despite passive controls) may be amplified for aging drivers due to the sensory losses experienced with aging.

The Handbook contains descriptions of 51 treatments in these 5categories, plus recommendations for their implementation. Nearly half of the treatments (24) pertain to intersections, such as left-turn treatments, signs, signals, lighting, and roundabouts. Another 8 treatments pertain to interchanges; these treatments are largely intended to improve the driver’s information and intended actions at the approaches to entrance and exit ramps, although lighting and delineation of the ramps themselves are discussed as well. There are 10treatments for roadway segments; many of these focus on improving the visibility and navigability of horizontal and vertical curves. Seven construction work zone-related treatments provide recommendations on the use of changeable message signs, static signs, and channelization for lane closures and other road work. Finally, the two treatments for highway-rail grade crossings (delineators and lighting) are intended to improve the visibility of crossings for approaching drivers.

Within each category of features, treatments are classified as proven practices or promising practices. The 33 proven practices are based on supporting evidence drawn from a comprehensive review of field and laboratory research addressing human factors and highway safety. The supporting information presented in part II represents the latest relevant information and data available to the authors at the time that the document was assembled. Some research findings have been carried forward from previous versions, while other findings are new since the release of the 2001 edition.

Promising practices include 18 additional treatments that are in use by one or more agencies around the country. Although FHWA has not evaluated them formally, they are believed to be of benefit to the aging population of roadway users. That conclusion is based on a subjective assessment by the FHWA staff participating in the development of the new edition of the Handbook.

For both the proven and promising practices, part I provides recommendations concerning their use in terms of specific design elements. In many cases, visual illustrations (that is, photographs or drawings) are included to provide examples of the treatments in use. In addition to the recommendations for the use of each treatment, the Handbook includes supplemental support from key references such as FHWA’s Manual on Uniform Traffic Control Devices (MUTCD), the American Association of State Highway and Transportation Officials’ Green Book (A Policy on Geometric Design of Highways and Streets), the Institute of Transportation Engineers’ Traffic Engineering Handbook, and other common guides.

Greg Johnson, chief operations officer at the Michigan Department of Transportation, says, “At MDOT, we have long recognized the need to adapt our system for the safety of users of all ages. We are following the latest research to improve the timing of WALK/DON’T WALK signals for pedestrians, but especially important is our attention to replacing signs that don’t reflect well at night. Those signs might look fine in the light of day, but they lose reflectivity over time, and nighttime driving is a special safety priority.”

Chapter 5 of part I of the Handbook recommends that some action words on portable temporary work zone signs have a minimum letter height of 8 inches (20 centimeters). According to Ed Yarbrough, construction safety engineer with the California Department of Transportation, “I conduct about 200 field reviews a year where the contractor has set traffic control. On a recent lane closure, I saw traffic control signage with a larger letter size. If these signs stand out to me and get my attention, then it is our hope that the larger lettering is having the same impact on the public, so that they can move through our work zones safely.”

Part II: Rationale and Supporting Evidence

In part II of the Handbook, the specific chapters, figures, and tables from the key references are listed for each treatment, followed by a detailed description of relevant research that documents the supporting evidence for the recommendations made in part I. The material in this part of the Handbook represents, to as great an extent as possible at the time of its development, the results of empirical work with aging drivers and pedestrians for investigations into the specific highway features of interest.

The FHWA team gave precedence to naturalistic and controlled field studies, augmented by laboratory simulations employing traffic stimuli and relevant situational cues. In addition, partII contains citations of crash data as appropriate. Some citations also reference studies showing the effects of changes in roadway design, where the predicted impact on the performance of aging drivers is tied logically to the results of research on age-related differences in detection, comprehension, response selection, maneuver execution, or other capabilities needed to negotiate the design element safely.

Comment and Conclusion

The treatments presented in the Handbook do not constitute a new standard of required practice. The final decision about when and where to apply the treatments remains at the discretion of State and local design and engineering professionals.

The 2014 Handbook is a resource that they can apply preemptively to enhance safety in jurisdictions with high numbers of aging road users, or it may be employed primarily as a problem-solver at crash sites. The transportation community can apply Handbook treatments in the design of new facilities and planned highway reconstruction projects, or use it to make improvements to existing facilities. The implementation of these treatments is intended to translate into real gains in safety and mobility for aging drivers, and many of the treatments have potential benefits for all users of the surface transportation system.

Before the new version of the Handbook was completed, Congress passed the MAP-21 transportation authorization bill. MAP-21’s Highway Safety Improvement Program, 23U.S.C. 148(g)(2) states the following: “If traffic fatalities and serious injuries per capita for drivers and pedestrians over the age of 65 in a State [increase] during the most recent 2-year period for which data are available, that State shall be required to include, in the subsequent Strategic Highway Safety Plan [SHSP] of the State, strategies to address the increases in those rates, taking into account the recommendations included in the publication of the Federal Highway Administration entitled Highway Design Hand-book for Older Drivers and Pedestrians (FHWA-RD-01-103), and dated May 2001, or as subsequently revised and updated.”

In 2013, four States--Alaska, Arkansas, Rhode Island, and Tennessee--reported that they fell under this special rule. In 2014, five States--Alaska, Arkansas, Hawaii, Maine, and Tennessee--were required to follow the rule. Since 2013, the Tennessee Department of Transportation (TDOT) has worked diligently to update its strategic highway safety plan to ensure that it addresses older drivers and pedestrians.

In January 2015, TDOT announced its updated plan. Under the infrastructure improvements emphasis area, strategy 6 specifically refers to improving “the safety of senior drivers by reducing roadway geometric deficiencies and enhancing roadway visibility on State and interstate highways.”

According to Brian Hurst, manager of TDOT’s Project Safety Office, “TDOT is addressing safety for all roadway users, including the growing population of senior drivers. The department has systemically increased the size of signs and striping along State-maintained roadways. The larger geometric roadway warning signs improve the distance [from which] a sign can be seen.”

In an effort to ensure knowledge sharing, FHWA and NHTSA are developing a Clearinghouse for Older Road User Safety, or ChORUS. FHWA and NHTSA envision this clearinghouse devoted to the safety of older road users as a one-stop shop for transportation officials, community leaders, older drivers, and their families and caregivers. The agencies will fill the clearinghouse with information about safer road designs for older road users, including drivers, pedestrians, cyclists, and persons with mobility or cognitive impairments; cost-effective roadway countermeasures to improve community safety for all; licensing information and policies; and other resources.

FHWA is working with the Roadway Safety Foundation to develop and manage the site along with NHTSA and its contractor. The clearinghouse will include a community forum and discussion boards where users can interact, and will be optimized for desktop computers, tablets, and other mobile devices from the outset. The goal is to have the clearinghouse up and running by the end of 2015.

FHWA Acting Administrator Gregory Nadeau underscored the agency’s commitment to the aging road user in his opening remarks at the 2014 North American Conference on Elderly Mobility: “We’ll intend to work closely with our Federal, State, local, and nonprofit partners by engaging in research and knowledge sharing that will provide safe mobility for older road users.”

There are a number of good reasons for FHWA, State DOTs, and local agencies to improve safety for older adults. Roadway designs that help older adults tend to be safer for everyone, regardless of age. And, if you are not over 65years old already, you will certainly benefit from these safety improvements when you become part of the older, golden, or senior population.

Marcus A. Brewer, P.E., is an associate research engineer with the Texas A&M Transportation Institute. He has more than 15years of experience in research on geometric design, traffic control devices, pedestrian mobility, and roadway safety. He served as the primary author for completion of the Handbook for Designing Roadways for the Aging Population. He holds a B.S. in civil engineering from The University of Kansas and a master’s degree in civil engineering from Texas A&M University.

Rebecca T. Crowe is a transportation specialist with FHWA’s Office of Safety. Crowe has been with FHWA for 14 years and manages the Older Road User program in addition to the Road Safety Audit, Motorcycle Safety, and Road Diet initiatives. She holds a B.S. in urban studies and planning from Virginia Commonwealth University and a master’s degree in transportation planning, operations, and logistics from George Mason University.

For more information, see the Handbook for Designing Roadways for the Aging Population, which is available in HTML and PDF formats through the Web site of the FHWA Office of Safety at http://safety.fhwa.dot.gov/older_users/handbook. Or contact Rebecca Crowe at 804–775–3381 or rebecca.crowe@dot.gov.