It’s been over a year since a Walmart semi-truck crashed into the limo van transporting Tracy Morgan and other comedians on the New Jersey Turnpike. The impact from the 110,000 plus pound truck left Morgan with serious brain trauma, several broken ribs and a broken femur, injured three other passengers and killed Morgan’s comedy writer, James McNair.

What caused the truck driver to rack a 6 car pile-up? The National Transportation Safety Board is citing sleep deprivation.

The Walmart truck driver had not slept for 28 hours. The crash could have been avoided if he had slowed down to the work zone speed limit of 45 miles per hour. Kevin Roper, the truck driver, had driven over 800 miles the night before the fatal crash, which injured 21 people total.

Sadly, incidents like this are too common. Drowsy driving causes 6 percent of all crashes and 21 percent of all fatal crashes. Shift workers like Roper are at an especially higher risk of drowsy driving. This is because of the odd hours truck drivers are expected to work.

There is one good statistic related to drowsy driving — it is almost always preventable. If your eyes start to feel heavy, or you can’t seem to stop yawning, pulling over to a safe location for a power nap can make a huge difference in your alertness. Refusing to drive when drowsy can save thousands of lives a year. To learn more about how to keep our roads safe, take a look at the Healthy Sleep Project and commit to staying awake at the wheel.

Updated Dec. 21, 2015