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More Rational Analysis Of Seniors' Driving Risks And Safety Strategies

A new American Automobile Association study argues that efforts to reduce driving by higher-risk seniors threaten their health. This analysis is backward: seniors benefit most from reduced driving and improved transport options.
Todd Litman | August 3, 2015, 5am PDT
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My mother-in-law is a product of her generation; her life stages are defined by her driving experiences. She tells stories about the cars she drove as a teenager and college student, the vehicles she and her husband drove when they married, their long summer road trips, and her ability to drive as a widow.

Her cognitive decline can also be charted by her driving experiences. In her late 70s she began to have frequent, minor "fender benders," that typically cost a few hundred dollars, which she paid out of pocket so they would not be recorded on her driving record. She spent thousands of dollars to purchase a smaller, more maneuverable car, but the collisions continued and escalated until, in her mid-80s she crashed into another vehicle, sending a young passenger to hospital, causing great stress and thousands of dollars in expenses. Despite these problems and growing evidence of dementia, she wanted to renew her driver’s license and was frustrated at the obstacles she encountered. I know other seniors with similar attitudes: they resist giving up driving and deny the problems that result.

Their behavior is irrational. It is far safer, more convenient and cheaper for higher-risk seniors to give up driving and rely on a combination of walking, public transit, and taxi travel. A new report by the American Automobile Association, Driving Cessation and Health Outcomes in Older Adults, is designed to validate irrational senior driving attitudes. It summarizes various studies which find positive correlations between seniors' driving cessation and health problems, and so argues that giving up driving is a health risk. This is a good example of bad research.

The study assumes that driving cession causes seniors' physical and mental declines when the impacts often go the other way: physical and mental declines cause driving cession. For example, my mother-in-law's driving cession and health problems are certainly correlated, but not because foregoing driving caused health problems; her dementia caused an accident which forced her to stop driving. Allowing her to drive again would certainly not improve her physical or mental health!

If we recognize that people's health tends to deteriorate with age, there are three possible outcomes:

  1. In response to declining health and ability, seniors voluntarily give up driving.
  2. In response to targeted regulations, such as special driving tests, seniors are forced to give up driving.
  3. Despite declining health and ability, seniors continue driving until they die, possibly in a traffic accident.   

In the first two outcomes, this study would find a positive association between driving cession and health, which it assumes is undesirable. Only the third outcome would show no association, and therefore be considered desirable in this study. In other words, the AAA's analysis considers it more desirable for seniors with declining health and ability to die in a vehicle crash than to voluntarily give up their driver's license and shift to other travel modes. This validates the statement, "I'll stop driving when you pry my bloody, dead hands from the steering wheel."  

The report explains, "Due to age-related declines in health, physical and cognitive functions, driving becomes more difficult for older adults. Many older adults eventually reduce or stop their driving activities, which may have adverse health consequences." Note the wording, "driving becomes more "difficult" rather than more "dangerous," which would acknowledge the trade-offs involved, and justify more aggressive actions to limit driving by higher-risk seniors.

The report does acknowledge that, "reducing or ceasing driving in older adults may confer some safety benefit" but concludes that, "Access to alternative transportation may not necessarily mediate the association between driving cessation and increased depressive symptoms…Effective intervention programs to ensure and prolong mobility, physical and social functioning for older adults are needed."

The report uses plenty of weasel words such as "might," "may," and "can," and the conclusions are vague enough that the AAA can deny that it actually encourages driving by higher-risk seniors, but its overall narrative is that driving cessation is extremely onerous and harmful to vulnerable seniors.

Similarly, a recent British study Keeping Older Drivers Safe and Mobile, surveyed older drivers concerning their abilities; it found that, although most drivers (84%) rated their driving ability as good to excellent, over 40% reported that they had forgotten where they left their car, 75% get into the wrong lane when approaching a roundabout or junction, 62% misread signs when exiting a roundabout, and 47% turn on the wrong switch (e.g. wipers instead of indicators) when driving. The report authors give this information a positive spin, emphasizing the importance that seniors place on their ability to drive, but providing no guidance on positive ways to reduce the need to drive, such as improving alternative travel modes and creating more walkable communities.   

Automobile associations and government agencies cannot totally ignore senior drivers' risks, so they promote senior driver refresher courses and offer safe driving tips, but there is actually no credible evidence that such programs reduce crashes. As with many other traffic safety strategies, safety gains can be offset if they lead participants to think that they are actually better drivers and so drive more intensively, an effect called risk compensation. According to the study, Ageing America and Transportation, senior driver training courses do little to reduce crash rates; the most effective programs are those that encourage drivers to become more aware of their limitations and reduce their exposure (i.e., driving). 

Crash data can be evaluated in various ways that can give different indications about senior driver risks, as indicated in the following two graphs. Accident rates per driver-mile tend to increase significantly for drivers over 65 years.

Motor Vehicle Crash Deaths Per 100 Million Vehicle-miles Traveled By Driver Age, 2008

However, this increased crash rate is partly offset by the reductions in average annual vehicle miles that occur when people retire. As a result, younger seniors (60-70 years) tend to have low per capita crash rates, a fact often repeated by senior driving advocates, although older seniors (70+ years) have high crash rates measured both per mile and per capita.

Motor Vehicle Crash Deaths By Age, 2008

Automobile associations have a conflict of interest on this issue: they want to retain members, which means supporting older drivers since drivers licensure rates are declining with younger generations.

There are other possible responses to seniors' driving risks that provide greater total benefits. Seniors can become safer and healthier if they shift from driving to other modes, particularly walking, since that reduces both crash risks and increases their fitness and health. The American Association of Retired Persons has terrific resources to help create more multimodal communities that increase everybody's safety, health and affordability.    

My research indicates that total traffic fatality rates (including pedestrians, cyclists, and bus and automobile passengers) tend to decline significantly as transit ridership increases in a community, as illustrated in the following graph. Cities with more than 50 annual transit trips per capita have about half the average traffic fatality rate as regions with less than 20 annual trips per capita, indicating that relatively modest increases in transit travel are associated with large traffic safety gains. This decline in fatalities is much greater than what could be explained simply by the passenger-miles shifted from automobile to public transit. 

Traffic Fatalities Versus Transit Trips

My hypothesis is that this partly reflects the ability of higher-risk groups (youths, seniors, drunks, and people with certain disabilities) to reduce their driving. Traffic safety experts must recognize that every time we want to reduce higher risk driving, for example by limiting teen or senior driving, we must provide viable alternatives. 

The American Automobile Association is ultimately harming its own members by publishing bad research concerning seniors' driving risks. Although many seniors initially resist change, they eventually adapt, and everybody benefits from policies that reduce higher-risk senior driving, and improve safer and healthier travel alternatives. 

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