Medical Issues Can Impair Driving

When reports surface about the dangers of impaired driving, headlines usually include alcohol, age, and the multi-purpose category of ‘distracted driving.’ Those rightfully belong at the top of the list.

Alcohol abuse is the greatest risk factor for motor-vehicle collisions, deaths, and injury. Typically, about one-third of the motor-vehicle related fatalities in the U.S. each year are alcohol-related. The same holds true for Massachusetts, which averages 400 alcohol-related fatalities annually.

Age has also taken center stage in regard to driving ability, as the older driver has become a growing national public health concern. Federal data show that drivers 75 years and older have higher rates of fatal motor-vehicle crashes than any other group except teens.

Distracted driving — especially talking and texting with cell phones — has also captured the spotlight after several tragic accidents. Such events have led the state Legislature to enact a new law banning texting, as well as the use of cell phones and other electronic devices, by motorists under 18.

While alcohol, age, and distracted driving capture most of the attention, it’s important to remember that sleep deprivation and many medical conditions also have the potential to cause impaired driving.

A driver’s visual acuity must be at a level where he or she has time to detect and react to pedestrians, obstacles, signs, and other vehicles in both daylight and darkness. State motor-vehicle departments have set minimum standards on vision requirements, including color and peripheral-vision standards.

Prescription drugs and other medications can affect sensory, mental, or physical functions, particularly for those who may be taking several medicines at the same time. Sedatives, antidepressants, muscle relaxants, codeine, and pain-control medicines are just some medications that can impair driving. People taking prescription drugs or over-the-counter medicines should read the instructions carefully and question their physician and pharmacist about possible side effects, how a drug might interact with others they may be taking, and how driving ability might be affected. Drinking alcohol when taking certain drugs can add to the side effects of the medication.

Diseases of the nervous system can impair muscle control, alertness, and consciousness. Patients with such conditions as dementia, seizures, severe pain, head injuries, Parkinson’s disease, multiple sclerosis, or stroke should be evaluated carefully by their physicians. This is especially important if the condition is progressive.

Patients with sleep disorders, such as obstructive sleep apnea or narcolepsy, as well as diabetes, cardiovascular disease, respiratory disease, psychiatric disorders, and musculoskeletal disabilities, should also be cautious. These conditions may impact cognitive, visual, and muscular abilities needed to drive safely.

The Mass. Registry of Motor Vehicles has established policies on such medical conditions as visual or cognitive impairment, seizures and loss of consciousness, arthritis and musculoskeletal disease, cardiovascular disease, and respiratory disease. Its Medical Affairs Branch may issue restrictions — or deny a license — based on these and other medical conditions. Licensees with a medical condition that makes them ineligible to drive have the responsibility to report their medical condition to the registry’s Medical Affairs Branch.

Motor-vehicle operators should know that the new law adopted by the Legislature in 2010 allows physicians and other health care providers to report in good faith any patient whom they have reasonable cause to believe is not physically or mentally capable of safely operating a motor vehicle. However, such reports cannot be based solely upon age or a diagnosis, and must be made on observations of the actual effect of the condition on a person’s ability to drive — a provision to prevent routine filings and discrimination in denial of licenses. The registry will then determine whether that person is competent to drive.

Individuals with medical conditions should become familiar with applicable laws. For information on state laws, visit The Mass. Medical Society’s publication Medical Perspectives on Impaired Driving, while developed for physicians, can be useful for others in describing medical conditions and how they affect driving. Download a free copy at

Dr. Janet Jankowiak is a geriatric neurologist and former member of the Mass. Medical Society’s Working Group on Impaired Drivers. This article is a service of the MMS.

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