PHARR – A Rio Grande Valley commercial truck driving instructor explained the difficulty truck drivers face on the road.

This after a tanker rolled over Thursday causing a gasoline spill and road closure along Highway 281 near Bluetown.

Willo Cordero said he began driving 18-wheelers in 1987. In 1991, he became a truck driving instructor.

Cordero said he's taught more than 8,000 students over the years. He believes many drivers on the road have no idea how long it takes a big rig to come to a complete stop.

"A fully loaded rig, weighing 80,000 pounds, at 55 mph takes 419 feet," he said.

Cordero said bringing the 18-wheeler to a complete stop isn't the only challenging aspect of driving a big rig.

He explained tankers carrying thousands of gallons of liquid can easily roll over if the driver is forced to take immediate evasive action. He added the liquid in the tanker can also cause a wave.

"The wave will push the trailer in the direction that it's going. So, if it gets up too high, you can imagine – I don't have anything circular with me right now – but if you can imagine that the tanker is round, the liquid is level as long as you’re leveled. But if you turn, the serge will do this number. So, the center of gravity goes from here to there,” he said.

The instructor explained the most skilled big rig drivers are always aware of their surroundings. He said they’re supposed to expect the unexpected.

Cordero said noncommercial drivers should provide extra distance between their vehicles and 18-wheelers to ensure the safety of roadways.