We can all learn to drive better. Improved cognitive function can help prevent motor vehicle crashes, including those involving runners, walkers and cyclists.
Most of us give little thought to driving, something we often take for granted. After all, many of us learned how to do it long ago.
However, reduced health, especially in the brain, can conceal impairments at any age. Drivers 65 years of age and older, and those 25 years of age and younger, have greater crash rates. Yet the global numbers behind the wheel of those between these age groups is astounding and could be a billion or more.
Cognitive impairment in all age groups, whether fleeting or ongoing, is the most common cause of crashes. In addition to other vehicles, encounters with walkers, runners, other pedestrians and cyclists is at an all-time high — these non-motorized travelers can also be impaired and at-fault too. (“Close-calls” and traffic violations are also serious problems commonly associated with an unhealthy state.)
This physical and mental health problem is also expensive — in the U.S. alone (not a population particularly highly accident-prone), annual traffic accidents in 2010 cost $1 trillion. Despite more high-tech safety features in both vehicles and on roads, crashes have only been reduced modestly, while the number of drivers, especially those over age 65, is rapidly rising.
Most motor-vehicle collisions are usually due to cognitive impairment from health-related conditions that lead to human error. Most common are driver distractions, often from cellphones or talking with passengers, especially while stressed, and eating or drinking (non-alcoholic beverages). Some reports indicate talking on a phone is as big a risk as driving when drunk.
Add to this drug-related impairment from alcohol — in any amount — and prescription and recreational drugs, and the more-common impairments of fatigue or sleepiness, even during the day, and it’s a formula for disaster.
A variety of human performance factors associated with better brain function can often significantly reduce driving errors and risk. Consider that, along with driver training or retraining, and better fitness, improving brain function with cognitive therapy can reduce driving risk. Ergonomics is important too. Just being aware of these issues is helpful.
Health Factors
Consider that fatigue and sleepiness are common, regular symptoms that can impair drivers, raising the risk of a crash. They are most common in people who are insulin-resistant (carbohydrate intolerant), especially after meals or during periods of hunger. In Western societies, this may include 90 percent of adults. And it’s not just those with diabetes, but anyone with blood sugar stress.
Physical fatigue and acute sleepiness from blood-sugar stress or lack of sleep (or a sleep disorder) can significantly affect reaction time; falling asleep at the wheel is more often a non-drug-related danger.
Localized muscle fatigue during driving is an important ergonomic risk factor. Consider something as simple as how one holds the steering wheel. Just because our parents or drivers’ ed instructors taught us to place our hands at the 10 and 2 o’clock position does not mean it’s correct. It isn’t. Driving in this position can increase muscle fatigue in the shoulders, arms and hands, impairing reaction times. Motor sports athletes and other driving professionals have long known the best driving position is with hands around 4 and 8 o’clock, where muscle fatigue is lessened allowing for faster reaction times. (Some professionals, such as police, are often taught to use 3 and 9 o’clock positions.)
Other hand positions can also be ergonomically inefficient and lead to slow reaction times. Rotating the hand up and placing it inside the steering wheel while turning is one.
Even proper function and control of the feet are important for effective driving, with professionals using one foot for the brake and the other for the gas.
While one of the biggest safety concerns is the rapidly growing number of older drivers, it’s less about the birthdate on their licenses and more related to physiological age — the ability to function as well at 70, for example, compared to 50. A good brain and body helps ensure better function at all ages.
Unfortunately, too many people develop cognitive impairments even when relatively young. This renders middle-aged and older drivers less able to take advantage of an important potential safe-driving feature — their years of experience. And, by removing licenses, it reduces independence in the older population.
Muscle imbalance leads to reduced ranges of motion, a physical impairment that can also raise driving risks. This is associated with the inability to turn the head sufficiently or quickly enough to see dangers, especially in blind-spots.
The “A” Factor
Awareness is a key feature of healthy cognition and safe driving. This includes being aware of a vehicle’s signals, lights and other dashboard features; our physical location (not being lost); and the presence of other vehicles, pedestrians and cyclists. In addition:
- Knowing the rules of the road, including driving courtesy and laws is vital. Signaling to change lanes or make a turn must be done before the action. Driving too slow in a left highway lane, or not knowing minimum and maximum speed limits also pose potential dangers.
- Being acutely aware each moment of all nearby pedestrians, cyclists and vehicles — especially those in a blind spot — is important.
- Not driving with lights on during the day, or especially forgetting to turn them on before dusk, is a problem.
- An awareness of vehicle maintenance is important too. Poor tire wear, ineffective brakes, broken signals or other malfunctioning lights can increase crash risk.
- Being aware of how often you’re on the road is important — more trips increase the risks. Organizing shopping, appointments and other travel needs can cut road time significantly. One trip with four stops vs. four separate trips not only reduces time on the road, but is also more economical.
Night Vision
Poor vision, especially at night, is a common risk factor for motor vehicle collisions. It’s a problem that often can be prevented or treated. Sometimes a simple adjustment can significantly help — turn down the lights inside your vehicle at night, including those on the dashboard. Inside light can impair driving vision because it constricts the pupils, reducing road visibility. In addition:
- Chronic illness can impair vision, especially at night. Diabetes, cataracts, glaucoma, and sometimes just a worsening nearsightedness are included. A complete eye exam can reveal most of these problems.
- With poor health comes various medications that can also impair driving, especially night vision. If a drug you are taking impairs night vision, or if any other problems do so, avoid driving at this time (or even during the day).
- Poor depth perception is also associated with impaired driving, and includes, for example, the loss of easy transition from reading the dashboard to objects on the road; or reduced speed of processing of different road information.
An important neurological state for healthy driving is soft-eyes. In a relaxing way it allows one to see the whole picture, rather than hard-eyes — staring or fixing the eyes at the car or road ahead, with higher body tension. Soft-eyes allows for the comfortable scanning of a wide angle of vision in front, the easy glance in rear and both side mirrors, including peripheral vision, helping to increase visual awareness all around.
In addition to vision-related health impairment that could affect driving, other sensory factors are associated with touch (hands and feet), hearing (not noticing horns, sirens, and turn signals that remain on too long) and vibration (the feel of raised center or outside lane markers). More importantly, the existence of one form of impairment often means at least one other exists too. Balance, to coordinate body movement, especially in the head and neck, and eye-hand coordination, are also important for safer driving.
Nutrition
In addition to blood sugar issues, which can impair brain function by reducing glucose for the brain, especially when fat-burning is poor and ketones are low, two other nutritional factors influence driving ability.
- Low levels of vitamin A can impair night vision. This nutrient is only found in animal products, especially egg yolks, liver and other organ meats, and fatty fish, foods many people avoid. The best dietary supplement of vitamin A is fish liver oil. (Fruits and vegetables don’t contain vitamin A, but beta-carotene, which poorly converts to vitamin A.)
- A common nutrition problem that can acutely affect driving is dehydration. Even a 1 percent water loss can affect cognition, and the risk of muscle dysfunction too. Many people avoid drinking liquids before and during driving to prevent having to find a toilet.
For many people it’s the combination of risk factors that becomes an even more significant problem. Consider all these high-risk situations:
- Driving during late afternoon commute time with high traffic volume, plus . . .
- Blood sugar disruption/hunger (you may not have eaten since lunch), plus . . .
- Increased mental stress (you’re slowed by traffic and have to get home), plus . . .
- Dehydration, plus . . .
- Reducing daylight . . .
These risks all add up.
