You have probably heard of the circadian rhythm but have not given it much thought. However, this wake-sleep cycle affects everyone, including the drivers of massive 18-wheelers.
If you are driving on I-15 near Temecula around three in the afternoon and you see a big rig that is having trouble staying within its lane, is this an example of the circadian rhythm at work?
The Federal Motor Carrier Safety Administration regulates the hours of service that commercial truck drivers put in each day. The focus is on preventing driver fatigue. Truckers may drive no more than 11 hours at a time and must follow each such shift with 10 consecutive hours off.
The Circadian Rhythm Connection
The wake-sleep cycle that your body experiences every day and every night is called the circadian rhythm. It connects to your internal clock and establishes levels of alertness. There is a natural lull in this rhythm between midnight and 6:00 a.m. and again between 2:00 and 4:00 p.m. Therefore, at three in the afternoon, the driver of the big rig you see weaving within its lane may be experiencing drowsiness as a result of the circadian rhythm lull.
The FMCSA advises drowsy truck drivers to pull over and take a nap, allowing 15 minutes to fully recover upon waking before getting back on the road. In fact, a nap can restore energy better than drinking a cup of coffee.
While there could be several reasons for that big rig to weave, such as overloading or driver distraction, fatigue is one of the most likely causes for erratic driving. Fatigue also presents the risk of a crash, which opens the driver, the trucking company and others to liability. The next time you are driving on I-15 or anywhere else in the early morning hours, or between two and four in the afternoon, remember the circadian rhythm: It affects truck drivers and everyone else around them.