Drivers must remain alert at all times. This is especially important for professional truck drivers whose massive vehicles can create devastating injuries in a truck-car crash.

A study finds that the level of driver alertness relates to the time of day. What does this mean and why is this important to you?

The circadian rhythm

Humans are subject to the circadian rhythm: the wake/sleep cycle that bodies deal with daily. There are periods every 24 hours during which people are naturally drowsy. These lulls occur between midnight and 6:00 a.m. and again between 2:00 and 4:00 p.m.

Truckers are often on the road in the late afternoon, and they might continue driving late into the night. They may not have had sufficient rest, and if they tire after long hours of driving, the natural lull of the circadian rhythm might affect their level of alertness.

FMCSA studies

According to the Federal Motor Carrier Safety Administration, most drivers are less alert during the nighttime hours, especially after midnight. An FMCSA study indicates that alertness in terms of driving is associated more with the time of day than time on task. The potential for accidents is also highest in the first hour after driving begins. This may be a result of sleep inertia, which means that a driver may suffer a temporary impairment in performing tasks such as cognitive functioning and reaction time during that first hour.

Staying safe

North Carolina sees its share of big rigs. They are easy to spot on the interstate but not so visible coming around a curve on a narrow mountain road. Remember the continuous cycle of the circadian rhythm and how it might affect a professional driver—and how that might affect you. Accidents happen, sometimes with life-changing injuries. Stay alert around big trucks and stay safe.