Driving is a complex task that depends on visual, cognitive, and physical functions that enable a person to see traffic and road conditions; recognize what is seen, process the information, and decide how to physically act to control the vehicle. Although the aging process affects people at different rates and in different ways, functional declines associated with aging can affect driving ability. For example, vision declines may reduce the ability to see other vehicles, traffic signals, signs, lane markings, and pedestrians; cognitive declines may reduce the ability to recognize traffic conditions, remember destinations, and make appropriate decisions in operating the vehicle; and physical declines may reduce the ability to perform movements required to control the vehicle. A particular concern is older drivers with dementia, often as a result of illnesses such as Alzheimer’s disease. Dementia impairs cognitive and sensory functions causing disorientation, potentially leading to dangerous driving practices. Age is the most significant risk factor for developing dementia—approximately 12 percent of those aged 65 to 84 are likely to develop the condition while over 47 percent of those aged 85 and older are likely to be afflicted. For drivers with the condition, the risk of being involved in a crash is two to eight times greater than for those with no cognitive impairment. However, some drivers with dementia, particularly in the early stages, may still be capable of driving safely. Older drivers experience fewer fatal crashes per licensed driver compared with drivers in younger age groups; however, on the basis of miles driven, older drivers have a comparatively higher involvement in fatal crashes. Over the past decade, the rate of older driver involvement in fatal crashes, measured on the basis of licensed drivers, has decreased and, overall, older drivers have a lower rate of fatal crashes than drivers in younger age groups (see fig. 1). Older drivers’ fatal crash rate per licensed driver is lower than corresponding rates for drivers in younger age groups, in part, because older drivers drive fewer miles per year than younger drivers, may hold licenses even though they no longer drive, and may avoid driving during times and under conditions when crashes tend to occur, such as during rush hour or at night. However, on the basis of miles traveled, older drivers who are involved in a crash are more likely to suffer fatal injuries than are drivers in younger age groups who are involved in crashes. As shown in figure 2, drivers aged 65 to 74 are more likely to be involved in a fatal crash than all but the youngest drivers (aged 16 to 24), and drivers aged 75 and older are more likely than drivers in all other age groups to be involved in a fatal crash. Older drivers will be increasingly exposed to crash risks because older adults are the fastest-growing segment of the U.S. population, and future generations of older drivers are expected to drive more miles per year and at older ages compared with the current older-driver cohort. The U.S. Census Bureau projects that the population of adults aged 65 and older will more than double, from 35.1 million people (12.4 percent of total population) in 2000 to 86.7 million people (20.7 percent of total population) in 2050 (see fig. 3). Intersections pose a particular safety problem for older drivers. Navigating through intersections requires the ability to make rapid decisions, react quickly, and accurately judge speed and distance. As these abilities can diminish through aging, older drivers have more difficulties at intersections and are more likely to be involved in a fatal crash at these locations. Research shows that 37 percent of traffic-related fatalities involving drivers aged 65 and older occur at intersections compared with 18 percent for drivers aged 26 to 64. Figure 4 illustrates how fatalities at intersections represent an increasing proportion of all traffic fatalities as drivers age. DOT—through FHWA and NHTSA—has a role in promoting older driver safety, although states are directly responsible for operating their roadways and establishing driver licensing requirements. FHWA focuses on roadway engineering and has established guidelines for designers to use in developing engineering enhancements to roadways to accommodate the declining functional capabilities of older drivers. NHTSA focuses on reducing traffic-related injuries and fatalities among older people by promoting, in conjunction with nongovernmental organizations, research, education, and programs aimed at identifying older drivers with functional limitations that impair driving performance. NHTSA has developed several guides, brochures, and booklets for use by the medical community, law enforcement officials, older drivers’ family members, and older drivers themselves that provide guidance on what actions can be taken to improve older drivers’ capabilities or to compensate for lost capabilities. Additionally, NIA supports research related to older driver safety through administering grants designed to examine, among other issues, how impairments in sensory and cognitive functions impact driving ability. These federal initiatives support state efforts to make roads safer for older drivers and establish assessment practices to evaluate the fitness of older drivers. The Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU), signed into law in August 2005, establishes a framework for federal investment in transportation and has specific provisions for older driver safety. SAFETEA-LU authorizes $193.1 billion in Federal-Aid Highway Program funds to be distributed through FHWA for states to implement road preservation, improvement, and construction projects, some of which may include improvements for older drivers. SAFETEA-LU also directs DOT to carry out a program to improve traffic signs and pavement markings to accommodate older drivers. To fulfill these requirements, FHWA has updated or plans to update its guidebooks on highway design for older drivers, plans to conduct workshops on designing roads for older drivers that will be available to state practitioners, and has added a senior mobility series to its bimonthly magazine that highlights advances and innovations in highway/traffic research and technology. Additionally, SAFTEA-LU authorizes NHTSA to spend $1.7 million per year (during fiscal years 2006 through 2009) in establishing a comprehensive research and demonstration program to improve traffic safety for older drivers. FHWA has recommended practices for designing and operating roadways to make them safer for older drivers and administers SAFETEA-LU funds that states—which own and operate most roadways under state or local government authority—may use for road maintenance or construction projects to improve roads for older drivers. To varying degrees, states are implementing FHWA’s older driver practices and developing plans and programs that consider older drivers’ needs. However, responses to our survey indicated that other safety issues—such as railway and highway intersections and roadside hazard elimination—are of greater concern to states, and states generally place a higher priority on projects that address these issues rather than projects targeted only towards older drivers. FHWA has issued guidelines and recommendations to states on practices that are intended to make roads safer for older drivers, such as the Highway Design Handbook for Older Drivers and Pedestrians. The practices emphasize cost-effective construction and maintenance measures involving both the physical layout of the roadway and use of traffic control devices such as signs, pavement markings, and traffic signals. The practices are specifically designed to improve conditions at sites—intersections, interchanges, curved roads, construction work zones, and railroad crossings—known to be unsafe for older drivers. While these practices are designed to address older drivers’ needs, implementation of these practices can make roads safer for all drivers. Intersections—Recognizing that intersections are particularly problematic for older drivers, FHWA’s top priority in its Highway Design Handbook for Older Drivers and Pedestrians is intersection improvements. Practices to improve older drivers’ ability to navigate intersections include using bigger signs with larger lettering to identify street names, consistent placement of lane use signs and arrow pavement markings, aligning lanes to improve drivers’ ability to see oncoming traffic, and using reflective markers on medians and island curbs at intersections to make them easier to see at night. See figures 5 through 8 for these and additional intersection improvement practices. Interchanges—Practices to aid older drivers at interchanges include using signs and pavement markings to better identify right and wrong directions of travel and configuring on-ramps to provide a longer distance for accelerating and merging into traffic. See figure 9 for these and additional interchange improvement practices. Road curves—Practices to assist older drivers on curves include using signs and reflective markers—especially on tight curves—to clearly delineate the path of the road. See figure 10 for these and additional curve improvement practices. Construction work zones—Practices to improve older driver safety in construction work zones include increasing the length of time messages are visible on changeable message signs; providing easily discernable barriers between opposing traffic lanes in crossovers; using properly sized devices (cones and drums) to delineate temporary lanes; and installing temporary reflective pavement markers to make lanes easier to navigate at night. Railroad crossings—Practices to help older drivers are aimed at making the railroad crossing more conspicuous by using reflective materials on the front and back of railroad crossing signs and delineating the approach to the crossing with reflective posts. See figure 11 for these and additional railroad crossing improvement practices. FHWA is continuing to research and develop practices to make roads safer for older drivers. FHWA also promotes the implementation of these practices by sponsoring studies and demonstration projects, updating its Highway Design Handbook for Older Drivers and Pedestrians, and training state and local transportation officials. For example, FHWA is supporting a research study—to be conducted over the next 3 to 5 years— on the effectiveness of selected low-cost road improvements in reducing the number and severity of crashes for all drivers. With the findings of this and other studies, FHWA plans to update its guidelines to refine existing or recommend new practices in improving older driver safety. In addition, FHWA is considering changes to its MUTCD—to be published in 2009—that will enhance older driver safety by updating standards related to sign legibility and traffic signal visibility.