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Topics: Extending Safe Driving Years Workshop, 2003.

Keynote Address
Martin Wachs, Director, UC Institute of Transportation Studies
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Martin Wachs addressed the importance of older driver research due to recent demographic trends, a clear safety risk to older drivers, and the complexity required to address possible solutions to increase safe mobility options for seniors.

The number of older drivers is increasing for two reasons. First, senior citizens are the fastest growing segment of the population. The population over age 65 is projected to grow from 35 million in 2000 to 78 million by 2050. Second, the next generation of senior citizens will rely much more on driving as a means of transportation than the current generation, which saw the introduction and adaptation of the automobile into mainstream culture. The increase in miles driven will put seniors at an additional risk.

Most importantly, older drivers are generally safe drivers: they have lower crashes per capita, they are less likely to drink and drive or speed, and they are more likely to self-limit their driving. However, older drivers have more crashes per mile than middle-aged drivers, they are more likely to be injured in a crash than a younger person, and they are more likely to be the party at fault. But testing on the basis of age is discriminatory and would not produce accurate predictions of driver performance.

"Living Longer, Growing Younger"
Paola S. Timiras, UCB Department of Molecular and Cell Biology

Paola Timiras focused on the interrelation of mobility and health. Active adults are generally fitter, more alert, and more engaged in life. Because the nervous system is "plastic" and changes throughout a person's life, the activities that older adults engage in directly affect their cognitive abilities in their later years. If older adults can continue driving well into post-retirement, Timiras said, they are more likely to feel independent. Conversely, the cessation of driving can lead to depression, especially if it means that a person is cut off from family, friends, and community activities.

Driving-related stress can also be good for older adults. Stress is now viewed by researchers as a healthy, important response to changes in the environment. It keeps people aware of their surroundings and alert. In fact, stress can improve a driver's vision and cognitive abilities, the very functions whose deterioration makes driving difficult. Thus, frequent driving can actually lead to an extension of safe driving years.

Older Adult Vision Acuity
Stanley Klein Professor, Optometry
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Stanley Klein highlighted applicable research from the Vision Science Graduate Group in the School of Optometry. Relevant work includes vision realistic rendering, visual cues for driving in a straight lane, optimal warning light design, a new method to test glare, useful field of vision as a predictor of driving performance, and the restrictions imposed by night vision loss.

Vision realistic rendering lets physicians, transportation engineers, and licensing officials see what the world looks like to people with various vision disabilities. For example, it can show what a restricted field of view looks like, by presenting a three-dimensional image of a scene, and comparing that with a three-dimensional view of the same scene, but through the eyes of a person with restricted peripheral vision. This technology, being developed by Brian Barsky, would be a highly useful educational tool engineers, planners, and policy makers who need a complete understanding of how diminished vision can affect driving.

Another development in the Vision Science Graduate Group is a method to evaluate glare. Older drivers, individuals who have had LASIK surgery, and others, may experience more vision difficulty (and therefore, difficulty driving at night) due to glare than others. Klein's method for measuring glare involves specifying the percent of scattered light in a scene, as well as the eye's ability to interpret that light. As Gunilla Haegerstrom-Portnoy's research concludes, visual acuity tests are poor predictors of other special vision measures. Evaluations of "useful field of view," glare, and others, may be an important tool to evaluate individuals' driving ability.

Elderly Drivers: Human Factors and Older Adult Cognition
Christopher Nowakowski, Development Engineer, UC Partners for Advanced Transit and Highways
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Christopher Nowakowski pointed out that age alone is a poor predictor of driving performance, which further complicates human factors research because care to classify functional decline as a result of a handicap is needed in order to specify better predictors of driving performance. But change does occur a result of age-related factors. Nowakowski reported on a study that young drivers turning left across oncoming traffic achoose a shorter "safe" distance when oncoming vehicles were traveling at 30 mph than at 60 mph. However, older drivers choose the same distance, no matter which speed the oncoming vehicles were traveling. Oher studies show that older drivers process the information in road signs more slowly than younger drivers and attend to fewer details when changing lanes.

Older Adult Drivers: Demographics, Driving Behavior Statistics
Judy Geyer, Research Associate, Traffic Safety Center
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Judy Geyer presented the components of risk associated with motor vehicle fatalities, and outlined how these separate components can motivate policy and safety improvements. Crash risk can be presented as a product of three distinct measures: exposure rates, crash rate per unit of exposure, and injury rate. From California 2001 crash data, Geyer calculated that these crash and fatality rates are higher for adults 65 and over than for middle-aged adults, while older drivers drive much less than other drivers. To address exposure rates, research should center on the impact of age on driving patterns. To analyze crash risk per exposure, research agendas should examine the impact of age on crash risk. Finally, the fatality risk per crash should be addressed by research on the impact of age on fragility. The separation of overall driving risk into exposure, crash, and fatality rates creates a framework for analyzing the effects of proposed policy and safety intervention program.

Sonoma Study on Older Adult Drivers
David Ragland, Director, UCB Traffic Safety Center
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Ragland summarized a study of older adult drivers in Sonoma which revealed the causes, (such as self-regulation due to reduced confidence in vision) and effects of driving reduction or cessation (such as a marked increase in incidence of depression). Variables that specifically address driving behaviors are gathered from both self-reported data (miles driven, type of driving, driving limitations, etc.) and from the California Department of Motor Vehicles (citations, crashes, license restrictions, license revocations). One of the study's findings is that vision is the primary medical factor that leads adults to self-imposed driving limitations. Also, driving cessation appears to coincide with a two (women) to four (men) hundred percent increase in average depression scores.

Panel and Audience Discussion Summary
Facilitator: Marilyn Sabin, Assistant Director for Operations, the California Office of Traffic Safety

Panel:
Ruzena Bajcsy, Director, UCB Center for Information Technology Research in the Interest of Society
Barbara Alberson, Chief, State and Local Injury Control Section, California Department of Health Services
Jim Misener, Principle Development Engineer, UC Partners for Advanced Transit and Highways
Patti Yanochko, Program Coordinator, Center for Injury Prevention Policy and Practice.

The discussion centered around three approaches: individual, environmental, and vehicular interventions. Barbara Alberson and Patti Yanochko began with a discussion of programs aimed specifically at environmental improvements. Yanochko, Alberson, and the audience discussed the importance of improved roadway design, applications of optometry and human factors research in roadway design, advocating the positive outcomes of driving, pedestrian-scaled communities, and implementation plans such as Caltrans' 25 Year Transportation Plan and the Federal Highway Administration's "Guidelines and Recommendations To Accommodate Older Drivers and Pedestrians," and roadside Intersection Decision Support (IDS) systems.

To address extending safe driving years at the individual, or driver's, level, Yanochko and Jim Misener proposed improved transit infrastructures to expand choice, receptivity to new devices such as collision warning systems, drivers' assessment, and drivers' re-education programs with insurance incentives. The audience discussion also considered familial assistance programs, self-assessed memory and cognitive tests as provided by agencies such as the AARP, the experimental 3-tiered older drivers' assessment program at California Department of Motor Vehicles offices, and diversity outreach.

Finally, Misener and Ruzena Bajcsy highlighted a platform for research applications to improve the safety and design of vehicles for older drivers.