Troopers believe that driver was impaired.
About 2 hours after that crash the driver of a second semi slammed into the back of a third big rig.
UHP told ABC 4 News those crashes could have been much worse.
When your dealing with a large semi truck the outcome's in an accident are often deadly.
Students at Sage Driving School learn their responsibilities when they get hands on training with the big rigs.
“It’s so big you've got to get used to how much control you have but you cant be afraid of the truck,” said student Joe Martinez.
To avoid accidents like the ones near Cedar City on Wednesday morning, the students are taught to respect and follow the rules to get a commercial drivers license.
“That means your not going to stop as quick, not going to turn as quick. A whole lot of training goes in to make the transition from what we learned to drive when we were 16 to driving a big rig on the road today,” said Sage School Director Guy Horn.
A CDL means a driver is held to a higher standard than the average driver. Especially when it comes to driving while impaired.
“.04 or greater is considered impairment,” said Corporal Todd Johnson with the Utah Highway Patrol.
When handling a truck that can weigh 80 thousand pounds or filled with hazardous material a certain amount of respect should be given.
“It takes a lot longer to stop a big rig than it does to stop a car its more weight, you want a much farther following distance,” said student Elliott Sorenson.
“You've got to be a lot more safe in these because it's not just your life it's the van full of family with the kids in it too,” said student Joe Martinez.
That’s a fact the Utah Highway Patrol says drivers in the accident on Wednesday might have forgot.
“This could have been catastrophic,” said Corporal Johnson.