Gayatri Devi, M.D.

Gayatri Devi M.D.

A Calm Brain

Are Older Drivers Safe?

Senior Driving Statistics: Older drivers versus younger drivers

Posted Apr 26, 2013

"An 86 year old man drove his 1992 Buick LeSabre into the Santa Monica Farmers' Market, flooring the accelerator as his car ploughed through throngs of shoppers. Nine adults and a 2-year-old were killed and more than 70 people injured... he confused the brake with the accelerator."

News reports like these prompt the question: Should there be stricter measures for ensuring safety with older drivers?  Since a third of persons over 80 suffer from dementia, should the elderly even be allowed to drive?

In my memory disorders practice, this is a question I dread: "Can I continue to drive?" or "I think Mom should stop driving... What do you think?"

In trying to find the right (and the just) answer, for the patient, for the patient's family, and for the rest of us, this is what I found:

The Facts

Fact: Among drivers 75 and older, 3% are involved in all crashes, 8% in fatal crashes, the lowest among age categories. Compare these numbers to the 18% and 16% rates for 35-44 year olds, the group I assumed was the safest.

Fact: Older drivers do not drink and drive. Among all drivers involved in fatal crashes in 2009, 3 percent of drivers aged 75 and over were drunk, a tenth less than drivers in their thirties (26-32 percent).

Fact: Older people, particularly women (why does this not surprise me?!) are more likely to voluntarily give up driving as they become concerned about their skills.  More than 600,000 drivers age 70 and older decide to give up driving each year.

Fact: Insurance rates for drivers older than 75 is minimally greater than younger adults and far lower than rates for teenaged drivers, reflecting accident rates in each group. Given the overall risk averseness of the insurance industry, this is a true testament to the safety record of older drivers.

Fact: Both the American Academy of Neurology and the Alzheimer's Association agree that a diagnosis of dementia is not a sufficient indicator of driving risk.  Over 75% of patients with mild dementia are able to pass road test and drive safely. This is not as improbable as it sounds. In people who have been driving for decades, driving is a procedural memory task residing in many areas of the brain. Common cognitive tests, on the other hand, evaluate memory for facts and events, which reside in specific brain regions.

Performance on visuo-spatial tasks are better correlated with driving ability than standard cogntiive tests. For example, older drivers are more at risk for intersection accidents, as they are less likely to scan the environment and focus straight ahead.  Such drivers will likely do poorly on visuo-spatial tests.

Fact: Finally, indulging in our fears of the threat of the older driver may put our elders at risk for dying from less familiar forms of transportation like biking, as shown in a recent Danish study.

Danes renew their driver's licenses periodically after 70, and annually after age 80. Renewals require a medical visit and the physician may opt, when concerned, to send some seniors for road tests. In 2006, Denmark added cognitive screening to these medical check-ups. After this screening began, fewer older drivers renewed their licenses, presumably because they failed the cognitive test. 

Data for a thousand days before and after screening began was matched to the Danish accident database, which collects all police-reported road accidents. Information on drivers younger than 70 was compared to data on drivers 70 and over, for motor vehicle, unprotected pedestrian, bicyclist and moped-rider fatalities. The results were astounding: while there was no change in fatalities from driving in either age group, there was a nearly 11-fold increase in deaths of seniors using other modes of transportation.

The authors conclude that cognitive screening programs for older drivers is an example of a political measure that seems sensible, but is not beneficial.

Fact: The counter argument is that older drivers are involved in more crashes per mile driven, and such crashes more often lead to death of the senior driver, who is generally more frail than her younger peers. 

We need to weigh all these facts when making a decision about seniors and driving safey.  In my opinion, gramps may be slow and drive me nuts by cruising at 40 mph on the Interstate, but he sure as heck is safer than most of us.  The first fender bender, more than the age of the driver, may be the best indicator of the need for further evaluation of driving.

Acknowledgment:  Dana Abrassart, MS, contributed to the research and writing of this blog.

References:

http://www.nytimes.com/2006/11/21/us/21sentence.html

Driving and Dementia. Alzheimer's Association Position Statement. Sept 2011

http://patients.aan.com/resources/neurologynow/event=home.showArticle&id=ovid.com:/bib/ovftdb/01222928-201006030-00008

Iverson D, Gronseth G, Reger M et al. Practice Parameter update: Evaluation and management of driving risk in dementia. Report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology. 2010;75(18): 1659

http://web1.ctaa.org/webmodules/webarticles/articlefiles/driving_life.pdf

Brown L, Ott B, Papandonatos G, Sul Y et al. Prediction of on-road driving performance in patients with early alzheimer's disease. J Am Geriatr Soc. 2005;53(1): 94-8.

Wagner J, Mürl R, Nef T et al. Cognition and driving in older persons. Swiss Med Wkly. 2011;140: w13136

Foley D, Heimovitz H, Guralnik J et al. Driving life expectancy of persons aged 70 years and older in the United States. Am J Pub Health. 2002;82(8): 1284-9.

Pollatsek A, Romoser M, Fisher D. Identifying and Remediating Failures of Selective Attention in Older Drivers. Curr Direc Psychol Sci. 2012; 21: 3-7.

Changing Mix. Insurance Institute for Highway Safety Status Report. 2012;47(9): 2-4.

U.S. Census Bureau. Licensed Drivers and Number in Accidents by Age. Statistical Abstract of the Unite States. 2012.

Siren A, Meng A. Cognitive screening of older drivers does not produce safety benefits. Accid Anal Prev. 2011;45: 634-8.

http://usatoday30.usatoday.com/news/nation/2007-05-02-older-drivers-usat1a_N.htm

http://www.ama-assn.org/ama/pub/news/news/older-driver-safety.page

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