HANGING UP THE KEYS

HANGING UP THE KEYS – Senior Drivers

Wednesday, April 23, 2014 – article by our newest Guest Author – Tony Dundon

hang up the keysOften, family members of an elderly person, usually their children, are faced with the difficult decision of trying to get them to give up driving. This can be a challenging and distressing time as few seniors are willing to voluntarily give up their car keys.

Adding to the problem is the dilemma of determining the exactly age at which one is considered too old to drive. As the process of aging varies from one person to the next, so does the age at which an elderly person can no longer safely operate a motor vehicle. This in itself creates controversy when regulating elderly driving.

Most Australian States allows seniors to keep driving provided they meet the same requirements as other road users. Persons above a specified age have to pass certain tests when renewing their licenses, up to and including a road test, or obtain a physician’s certificate stating they are medically fit to operate a motor vehicle.

Notwithstanding this, it is important to note that the majority of older drivers are crash-free and for many seniors, the ability to drive a motor vehicle is a central aspect of their independent living. As legislation reflects, to restrict an individual’s driving rights based only on chronological age is inappropriate and discriminatory (Ball and Owsley, 2003; Goode et al., 1998).

So maybe the decision to give up driving can be deferred.

Assuming attitude, physical and mental competence are un-impaired, spatial awareness due to diminishing perception, is the major cause of intersection accidents. In Australia in 2011, there were 295 fatalities involving seniors aged 60 years or older, representing 22.9% of the national road toll. Of these, 107 fatalities involved adults aged 60-69 (8.3% of the national road toll), while 188 were adults aged 70 years or older (14.6% of the national road toll). The most common causes of crashes involving older drivers include:

· Failure to see and/or yield to other road users;

· Complex road environments (e.g. Intersections, roundabouts);

· Sudden illness or blackout;

· Lack of awareness of traffic signals; and

· Low speed manoeuvrers

During the process of normal ageing there is substantial neural loss and a gradual decline in dynamic vision, including peripheral vision (Tran et al., 1998; Willis & Anderson, 2000; Wist, Schrauf, & Ehrenstein, 2000). Wojciechowski, Trick, and Steinman (1995) found substantial age-related deterioration in motion sensitivity in the peripheral visual fields; likewise Panek, Barrett and Sterns (1977) reported a decrease in the extent of the total visual field from 170 degrees in young adults to 140 degrees by the age of 50 years.

This reduction in peripheral vision is important because people with poor peripheral vision are believed to have twice the crash rate of those with normal peripheral vision (Morgan & King, 1995); additionally, poor peripheral vision is associated with problematic driver performance (Wood & Troutbeck, 1995).

Ball, Beard, Roenker and Miller (1988) examined the change in peripheral vision as a function of age. They examined peripheral vision in the context of a so-called “useful field of view” which they defined as the visual area from which information can be acquired within one fixation of the eye. They examined the effects of age on performance on a peripheral localisation task in 24 young (aged 22-23 years), middle-aged (aged 40-49 years), or older (aged 60-75 years) adults. Their findings indicated that regression models which best captured the effects of eccentricity, centre task demand, and practice on peripheral localisation performance was different for each age group. For example, age was only a statistically significant predictor of performance in the models for the middle-aged and older groups; similarly, effect of distractors was only statistically significant for the older group. Nonetheless, all three regression models successfully predicted the extent of the useful field of vision when distractors were placed within the visual field.

Burton (1997) confirmed that older individuals need more time to scan the visual scene and therefore need longer to perceive targets presented in peripheral vision. Test participants searched for a target presented among a number of distractor items. When they were given as much time as they needed to find the target, their search times were independent of the number of distractor items and the search time increased with distance from the fixation point, for all ages. However, older participants’ searches required more time at all target eccentricities.

According to a study from the University of California, Riverside and Boston University, seniors can improve their vision with perceptual training. Researchers G. John Andersen, professor of psychology; Rui Ni, formerly a postdoctoral researcher; graduate student Jeffrey D. Bower; and Boston University psychology professor Takeo Watanabe conducted a series of experiments to determine whether repeated performance of certain visual tasks, that are at the limits that one can see, can improve the vision of adults older than 65.

“We found two days of training, in one-hour sessions, with difficult stimuli resulted in older subjects seeing as well as younger college-age subjects,” Andersen said. “The improvement was maintained for up to three months and the results were dependent on the location in the visual field where the stimuli were located — suggesting that the brain changed in early levels of visual cortex.” The visual cortex is the part of the brain that processes visual information. “Given the clear impact of age-related declines in vision on driving, mobility, and falls, the present study suggests that perceptual learning may be a useful tool for improving the health and well-being of an older population,” the researchers concluded.

To keep the roads safe and the aged population mobile and productive, these clinical observations should influence regulators and road designers. I believe as part of the requirements of seniors to maintain their license, they should have mandatory perceptual training every 6 months.

Furthermore, councils need to Audit all intersections and merges and those with dependency on peripheral vision less than 140 degrees should be redesigned and rebuilt.

In addition, families need to have the difficult conversation with their elder members and help them to determine if their driving skills and health conditions place them or the public at risk.

References

Cite This Page:
University of California – Riverside. “Perceptual training improves vision of the elderly, research finds.” ScienceDaily. ScienceDaily, 24 November 2010. www.sciencedaily.com/releases/2010/11/101122172137.htm.

http://www.carrsq.qut.edu.au/publications/corporate/older_roaduser_fs.pdf

http://digital.library.adelaide.edu.au/dspace/bitstream/2440/31800/1/CASR019.pdf

http://www.mpe.com.au/safety-and-risk-consulting/Safety-and-Risk-Consulting.htm

About the Author:

Tony Dundon,

Project manager safety

Maintenance and Project Engineering – MPE

p +61 447767000

e tdundon@mpe.com.au


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