Live Well, Live Long : Road Map to Driving Wellness

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Problems with Physical and Psychomotor Function

The following factors are affected by problems with physical and psychomotor abilities:

Reaction Times
Aging decreases the speed and coordination of movement. Yet in certain well-learned tasks such as routine driving, older adults seem unimpaired. Unfamiliar settings, emergency stops for pedestrians or animals, and "surprise" maneuvers made by other vehicles may bring out the effects of slowed reaction time. ⁵³
Strength and Flexibility
Aging affects head and neck mobility, muscle strength, endurance and flexibility necessary for operating vehicle controls and turning to view traffic. Arthritis is a common condition that restricts movement, slows reaction time and, if painful, affects concentration. Arthritis or other conditions limiting joint mobility can make it difficult to safely get in and out of a vehicle or fasten a safety belt.

Conditions Affecting Motor Function and Driving⁵⁴

Condition	Effect on Driving	Risk of Developing Condition with Aging	Crash Risk (Summary of Research Findings)
Arthritis⁵⁵	Dexterity loss, affecting the use of dashboard controls Reduced range of motion, affecting reaching and fastening safety belts Loss of strength required for turning the steering wheel or pressing the gas or brake pedals	50 percent of middle-aged adults 80 percent of people ages 70+ ⁵⁶	May increase crash risk
Sleep apnea⁵⁷	Disrupts sleep at night, causing daytime drowsiness. Affects alertness when driving Falling asleep at the wheel	_____	May increase crash risk
Chronic pulmonary disease⁵⁸	_____	_____	May increase crash risk
Lower-limb abnormal-ities	Lessened ability to move the foot between the brake and accelerator	Increased severity and pain	Twice the crash risk with 3 or more foot abnormalities, compared to people with 2 or fewer
Falls	_____	More than one-third of adults ages 65+⁵⁹	Greater crash risk significantly related to having fallen within the past 2 years
Cold feet or legs on exposure to cold	Slower mobility, affecting dashboard operations and slowing depressing of the brake Weak grip on the steering wheel	_____	May increase crash risk
Bursitis	Lessened range of motion for arm and leg joints, resulting in decreased flexibility, which may affect reaction time	_____	Increased crash risk
Back pain	Ability to move one's legs affected Intense pain, which may distract the driver	_____	Crash risk 1.5 times higher than for older drivers without back pain

Conditions with Multiple Effects

Diabetes

Diabetes can affect vision, physical function and cognition. In terms of vision, diabetic retinopathy - loss of blood circulation to the eye's retina - is a serious condition which, left untreated, may cause blindness. The condition develops in 70 percent of people with insulin-dependent diabetes. As the disease progresses, it seriously affects how well drivers can see the road and traffic.

People with diabetes who experience pain or loss of feeling in their feet may have difficulty moving their feet. Diabetes can affect a person's ability to operate car controls such as the brake and gas pedals.

In the short term, diabetes can cause blood glucose (sugar) levels to reach too high or too low a level. As a result, the person with diabetes can feel sleepy, light-headed or confused, or even lose consciousness or have a seizure. These cognitive changes can affect driving alertness and the ability to quickly respond to traffic demands, pedestrian movement or even operation of the vehicle.

Parkinson's Disease

Parkinson's disease can cause arms, hands, or legs to shake - even when relaxed. The disease affects balance and the ability to start moving after being still. Parkinson's affects driving by limiting the ability to:

React quickly to a road hazard
Turn the steering wheel
Use the gas pedal or push down the brake⁶⁰

Heart and Circulation Problems

People with irregular heartbeats can experience light-headedness and disorientation, which affects the ability to interpret and respond to traffic. Crash risk increases for those with irregular heartbeats.⁶¹

Conditions Affecting Multiple Organ Systems and Driving ⁶²

Diabetes and Associated Conditions⁶³

Effect on Driving

Risk of Developing Condition with Aging

Crash Risk (Summary of Research Findings)

Blood sugar not in balance

Loss of consciousness

Vision impairments

70 percent of people with insulin-dependent diabetes mellitus (IDDM) develop proliferative diabetic retinopathy

40 percent develop macular edema. Both conditions, if untreated, frequently lead to serious visual loss⁶⁴

Crash risk up to four times greater with diabetic retinopathy

Cardiac (and Cardiopulmonary) Conditions

Effect on Driving	Risk of Developing Condition with Aging	Crash Risk (Summary of Research Findings)
Varies according to the individual and type of condition	Commonly, cardiac conditions resulting in arrhythmia	Crash risk greater with people with irregular heartbeat or a heart condition than those without an irregular heartbeat

Renal Disease

Effect on Driving

Risk of Developing Condition with Aging

Crash Risk (Summary of Research Findings)

Muscle weakness in patients with adrenal cortical hyperfunction (Cushing's disease), necessitating driving cessation

Headache, dizziness or blurred vision. If patients improve after treatment, they may again be able to resumed driving.⁶⁵

_____

Crash risk significantly related to the presence of renal disease

A more detailed explanation of these conditions and the studies of their effect on driving is available in the National Highway Traffic Safety Administration (NHTSA) guidebook Safe Mobility for Older People.

⁵³ NHTSA, "Attention."

⁵⁴ Ibid.

⁵⁵ NHTSA (Aug. 2001) "Physical Risk Factors" (based on Marottoli (1996)). Older Road User Research Plan.

⁵⁶ AAA Foundation for Traffic Safety (2001) How to Help an Older Driver: A Guide for Planning Safe Transportation 6. Washington, DC: American Automobile Association. Also available on the World Wide Web: www.aaafoundation.org/pdf/Odlarge.pdf.

⁵⁷ NHTSA, "Physical Risk Factors."

⁵⁸ Ibid.

⁵⁹ National Center for Injury Prevention and Control. "Falls and Hip Fractures Among Older Adults." Fact Sheet. Retrieved from CDC on the World Wide Web: www.cdc.gov/ncipc/factsheets/falls.htm.

⁶⁰ NHTSA (2003) Driving When You Have Parkinson's. Retrieved from the World Wide Web at www.nhtsa.dot.gov/people/injury/olddrive/Parkinsons%20Web/index.html.

⁶¹ NHTSA, Safe Mobility for Older People Notebook.

⁶² Ibid.

⁶³ American Diabetes Association. Available on the World Wide Web: www.diabetes.org.

⁶⁴ National Center for Chronic Disease Prevention and Health Promotion. "The Prevention and Treatment of Complications of Diabetes Mellitus: A Guide for Primary Care Practitioners." Diabetes Public Health Resource. Retrieved from CDC on the World Wide Web: www.cdc.gov/diabetes/pubs/complications/eye.htm.

⁶⁵ Canadian Medication Association (May 2000) "Metabolic Diseases." Determining Medical Fitness to Drive: A Guide for Physicians (6th ed.). Retrieved from CMA on the World Wide Web: www.cma.ca.

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