Truck driving is an important profession -- but it can also be a dangerous one.
A few recent tractor-trailer crashes have grabbed the public's attention.
Last week, a semi-driver slammed into a limo-bus carrying actor Tracy Morgan, killing one person on board.
According to the criminal complaint, that driver had been awake for more than 24 hours at the time of the crash.
And just yesterday -- a truck driver said he crashed after falling asleep at the wheel on I-29 north of Summit.
That driver was wearing a seat belt and will be okay -- the same cannot be said for his cargo of Bud Light.
We all know how dangerous distracted driving can be, but fatigued driving could be even worse, especially in a big rig.
"As a driver gets fatigued their reaction time definitely is delayed. The worst case scenario is they could fall asleep behind the wheel," said State Trooper Matt Koll.
He checked for tired truck drivers at a Highway Patrol Operation for safer roads.
He said truckers are required to keep track of their driving hours in a log book.
"An over the road truck driver is allowed to drive 11 hours in one period of time and then they would be required to take a 10 hour rest break," he explained.
Truck driver Jason Loy Thomas said that's not a problem if it means keeping people alive.
"Depending on the load and cargo, I'm driving up to an 80,000 pound weapon," said Thomas.
He added even if he's driving the regulated hours he stops to take a break when he needs to.
"If you're driving over 10-12 hours in a vehicle, the mind starts to go. You start to see things and look at things. You can't maintain this level of intensity all the time," he said.
Thomas said it's too dangerous if he doesn't rest.
"If I strike something, what ever it is that I strike is probably going to be in pieces. I'll probably walk away no problems," he added.
He said truck driving isn't easy especially if you're tired.
"A lot of what we do is a dangerous job. And it requires you to be on point and requires you to know what you're doing and to think about it. You can't go on autopilot in these trucks. You do that, and you're in the ditch," said Thomas.
The South Dakota Highway Patrol does 25,000 safety inspections every year just to make sure the roads are safe.
Thomas says if he's going 65 MPH in his truck and needs to come to a complete stop it will take him 662 meter, that's more than a third of a mile.
And if he's tired he can't react as quickly as he needs to.