When most drivers think about “impairment,” they think of alcohol consumption, or possibly the use of illegal drugs. Those substances can certainly impair a driver’s judgment and ability, but they are by no means the only things that can do so. In fact, anything that slows your perception and reaction time can be an impairment, including distractions.
Physical impairments can result from injury or illness. That’s why the Federal Motor Carrier Safety Administration (FMCSA) prohibits driving after an injury that impedes a driver’s ability to perform the safety functions of the job. A broken hand, for example, might be set in a cast that doesn’t allow the driver to properly grip the steering wheel. A broken leg could impede the ability to use throttle and brake pedals.
After healing from such injuries, a driver may be required to pass a Department of Transportation (DOT) physical exam before being allowed to return to work.
There are other physical ailments that may not be listed in the regulations but can still impact a person’s driving ability. For example, a driver might be convinced to “tough it out” when beset by an illness such as the flu. The danger, however, is that nausea and fatigue can divert attention away from the task of driving safely. Often, it’s much safer to take the time to recuperate before hitting the road again.
Over-the-counter (OTC) drugs used to treat minor illnesses can also impair safe operation of a vehicle. Some allergy medications, for example, come with warning labels indicating they can cause drowsiness. One popular allergy medication, Benadryl, contains 25 milligrams of diphenhydramine HCL — the same medication, at the same dosage, found in the popular sleep aid ZzzQuil. It’s also found in Tylenol PM and other pain medications that include “PM” in the name.
Always check medication labels carefully for warnings of drowsiness or other impairments, and always follow directions. Unless you’ve used the medication before and are familiar with its effects, wait until you’re stopped for the day to take it. If you’re in doubt, a pharmacist can be a great resource for information. If you consult one, make sure you ask if it’s safe to take the medication and then drive a heavy truck.
Your emotions can also impair your ability to drive. When your mind is focused on your anger at your dispatcher, for example, your decision-making abilities can suffer. If you’re distraught about events back home, such as a death in the family, you won’t be at your best behind the wheel.
Every situation — and every person — is different, and only you can decide if it’s safe for you to drive. At the least, consider that your reactions to hazards might be slower than usual. Taking a break or a short walk, or making a phone call to someone you trust may help get you in the right frame of mind. If not, park it until you’re ready.
Another impairment factor every driver deals with fatigue.
According to the U.S. Centers for Disease Control (CDC), driving while drowsy can cause impairment similar to that caused by alcohol consumption. Drowsiness makes a driver less attentive, slows reaction time and affects decision-making ability. The CDC estimates that being awake for 18 hours is the same as having a blood-alcohol content (BAC) of .05%, which is above the legal limit for commercial vehicle operators.
Sometimes drowsiness is expected, particularly near the end of a long shift or after a particularly stressful day. But some causes of drowsiness aren’t as easy to identify, and sleepiness can creep up on you when you aren’t expecting it.
Irregular sleep patterns, a common occurrence in the trucking industry, can result in poor sleep — and later, drowsiness. Poor sleep, caused by noisy conditions or other factors, can have the same result. As discussed earlier, some medications can cause drowsiness — but other medications might keep you from sleeping so you don’t get enough rest for your next shift. Many OTC medications include caffeine as an ingredient. Taking a BC Powder or an Excedrin Migraine painkiller before bed adds caffeine to your system and can interfere with sleep. Many energy drinks also contain caffeine.
Drowsiness can also be caused by sleep disorders, such as sleep apnea, that interfere with the body’s ability to obtain restful sleep. People with sleep disorders often snore loudly and can even stop breathing while asleep, causing the body to react spasmodically as the victim gasps for air. In many cases, the sufferer isn’t even aware that it happens; the only symptoms are fatigue and drowsiness the next day. Sleep apnea is more common among overweight and obese drivers, especially those who smoke, but can impact anyone.
Diagnosing sleep disorders often involves an overnight sleep study, either in a clinical setting or using take-home equipment. Treatment often involves use of a continuous positive airway pressure (CPAP) or automatic positive airway pressure (APAP) machine to keep airflow to the lungs consistent through the night. If you suspect you have a sleeping disorder, get tested.
Food can be a cause of drowsiness, too. A big meal can result in the desire to nap when you’re trying to make miles. When driving, it’s often best to eat smaller meals, even if you have to eat more often.
Keep in mind that mechanical issues with your vehicle can cause impairment. A burned-out headlight reduces your ability to see. Worn windshield wipers may not keep your view ahead clear. Mirrors that are dirty, out of adjustment or blocked by items in the cab don’t provide all the needed information.
Finally, willful impairment is all too common. Willful impairment occurs when a driver chooses to divert attention away from the task of driving safely and onto something else, like answering a text message on a phone. Modern phones demand attention for calls, texts, social media alerts and more. Some states require hands free operation of phones and other devices, others prohibit their use while driving altogether.
Communications or other devices provided by a carrier can be misused, too. Even dash displays like the LCD screens used for GPS or to control music or other features can distract, if you choose to let them.
In the end, the best practice is to maintain an eye scan and keep your concentration on your most important task — getting home safely.
Cliff Abbott is an experienced commercial vehicle driver and owner-operator who still holds a CDL in his home state of Alabama. In nearly 40 years in trucking, he’s been an instructor and trainer and has managed safety and recruiting operations for several carriers. Having never lost his love of the road, Cliff has written a book and hundreds of songs and has been writing for The Trucker for more than a decade.