It’s no secret that well-rested truck drivers run more miles each day. In fact, studies show that drivers who sleep well run around 10% more miles per week. That translates to a whole lot more productivity for a trucking fleet, including:
- Better on-time delivery performance
- Fewer severe accidents
- Higher retention levels
The science of sleep is one of the most misunderstood subjects in the trucking industry, yet it’s the most important when it comes to fleet utilization and driver productivity levels.
FleetRisk Advisors conducted a six-month study where half the driver population (n=1,765) at a large truckload carrier were educated in the science of sleep. They found that:
- Accident frequency dropped by 15%
- Severe accident rates were 7.2 times lower
- Drivers were 33% less likely to voluntarily quit
Compared to the control group, sleep-educated drivers also ran 10% more miles per tractor-week while being 100% compliant with hours of service regulations.
How does more sleep equal more miles and pay?
For a truck running 2,500 miles per week, that’s the equivalent of adding another 250-miles to the weekly total. And with linehaul spot rates around $2.40/mile this week, that represents an increase of $600 per week in revenue — or roughly an additional $30,000 per year. Underpinning these productivity gains is the education of drivers and dispatchers in the science of sleep, and ensuring drivers get the right quantity and quality sleep.
While this may sound counterintuitive, summer is the best time to begin the educational journey. Summer is in fact one of the worst times of the year for sleep-related accidents. Or to be more precise, there are more lack-of-sleep related accidents.
During the months of July and August, truckload accident frequency typically increases by around 12% above the average of the prior three months during spring and early summer.
Why do we see higher accident rates during summer?
As we work though the peak of summer, travel and vacation, we normally see truck accidents increase. But it’s not all due to more people being on the roads.
One of the most underestimated factors is sunlight. In this case, it’s too much of it at this time of the year. More sunlight — plus Daylight Saving Time — means more time after work to enjoy life. But it also means sleep is delayed well into the evening.
The sleep-wake cycle is driven primarily by the rising and setting of the sun. When the eyes receive less light during the evening, melatonin — a hormone that regulates our sleep-wake cycle — is produced. This is an overly simple description of human physiology, but it does show how more daylight hours tends to mean fewer hours of sleep.
Using Omaha, NE, in the center of the country as an example, its shortest day last winter was December 21 when the sun rose around 8 a.m. and set at 5 p.m. That’s just nine hours of daylight. In contrast, their longest day was six months later on June 21. The sun rose just before 6 a.m. and set 15 hours later at around 9 p.m.
That means there’s six hours more daylight over the course of 182 days. If the driver doesn’t use blue-light blocking sunglasses and/or darkened sleeper cab to trick the brain into thinking sunset has occurred earlier, the driver can experience a six-hour delay in the timing of sleep onset. (Of the colors in the visible light spectrum, research shows that blue light has the most impact on the timing of the circadian rhythm — the process that regulates our sleep-wake cycle.)
Regardless of how long a driver’s on-duty work period is, or the time of day they start work, the timing of sunlight determines the timing of the sleep wake cycle. In summer, where sunset can be much later in the evening, research shows that drivers who take a ten-hour break during the day only average 4.5 hours of sleep. Compare this to 10-hour breaks at night where drivers get around 7.5 hours of high-quality sleep.
Truckers who sleep during the day typically get around 2.5 hours less sleep each day compared to their dayshift colleagues who sleep at night. And herein lies the challenges of prescriptive hours-of-service regulations where we take a one-size-fits-all approach.
So what and now what?
Now’s the time for brokers, carriers and shippers to be asking how drivers are doing. Don’t assume that just because the driver has had a 10-hour or more break that they’ve actually had enough sleep. Or any at all in some cases.
Drivers can follow these tips to get more high-quality sleep:
- Avoid coffee or sodas with caffeine after 3 p.m. or 3 a.m. if planning on sleeping within six hours. Caffeine has a half-life of six hours and it could delay sleep, depending on caffeine tolerance.
- Nap in blocks of 90-minutes.
- Strive to get two consecutive periods of night sleep every seven days. Don’t count the number of hours of sleep, but do count the number of sleep cycles (90-minutes) per every 24-hours.
Drivers should aim for at least six hours or four sleep cycles of sleep every day, and then supplement that with strategically timed naps throughout the day and week.
