Unbelievable Facts about 18 Wheelers (We Bet You Never Knew)

The ubiquitous tractor-trailer combination plying America’s roads is such a common sight, we tend to overlook some downright amazing things that are unique to 18 wheelers. Some of these things are just completely unbelievable. For example, at the end of their useful life all the little tractor-trailers go live out their days in a great big pasture in Kentucky (okay, that’s unbelievable because it’s simply not true—but it would be cute, you have to admit). We thought you might enjoy reading some unbelievable but actual facts about 18 wheelers as you weigh the notion of becoming a professional, highly trained commercial truck driver.

Strength in Numbers

Those trailers on the back of the tractors are the reason the vehicles are called “semis.” They have a semitrailer, something that needs to be pulled around. They are articulated, meaning they can negotiate turns despite their 65-foot length. The country is bedecked with trailers, nearly six million of them, and around two million tractors.


Consider your average family vehicle. The Insurance Institute for Highway Safety gives a curb weight range of passenger vehicles from 2,001 pounds (minis) up to 5,750 pounds (SUVs). The heaviest SUV at 5,750 pounds is a mere seven percent of a tractor-trailer’s maximum weight. The truck is more than 13 times heavier. At the lighter end, the mini is a wispy 2.5 percent of the 18 wheeler; the semi is nearly 40 times heavier than the mini.


The average sedan proudly tools around with up to 200 horsepower under the hood. This is a third the typical horsepower of a diesel engine in a semi. For those of you who know torque, consider this:

  • Family car—100 to 200 foot pounds of torque
  • 18 wheeler—1,000 to 2,000 foot pounds of torque

Specialty tractors, such as the U.S. Army’s M1070A1 heavy equipment tank transporter (for when you absolutely, positively don’t want to leave your tank out where the neighbor kids will find it) has an engine developing 700 horsepower with 1,900 ft-lbs. of torque that can move at an astonishing 80 kph carrying a tank (and the tank’s crew—the M1070A1 is like calling AAA for the battlefield; they come and get you).

Turning Radius

Some people gripe when they have to do a K-turn on a country road (“I told you Aunt Martha was not on this cowpath!”) but imagine navigating an 18-wheeler, which needs 55 feet of turning radius. This is why tractor-trailers have really, really big side mirrors. You have to be proficient in backing up, because most roads are a scant 24 feet wide.

How Many Wheels?

An 18 wheeler has 19 wheels. The “fifth wheel” is the round metal plate that accepts the trailer’s kingpin to get the two pieces together. Okay, it isn’t exactly a wheel, but it is called a fifth wheel. The double wheels elsewhere are nicknamed “dualies” and are for safety and weight distribution.

Safety First, Last, Always

Today’s 18 wheelers are safer in many ways than the passenger vehicles swarming around them like remoras on sharks. This is because trucks must operate safely in all weather at all hours of the day and night. They represent a major investment, so the owners want to preserve not only their drivers but their tractors, too. Collision avoidance systems, cameras, lane departure warning systems, roll stability control and other features that are usually expensive options on passenger cars are nearly standard on modern semis.

These safety features are needed at least in part because a loaded semi needs around two football fields of road to come to a complete stop from 55 mph. This is 40 percent more than a car needs. Professional, educated truck drivers learn to look far down the road to avoid needing to hit the air brakes.

truck driver salaryMoney Machines

Driving a tractor-trailer is one of the few jobs in which someone without a high school diploma can still earn a good living. Attend commercial driving school, get your CDL, and you can make good money. The Bureau of Labor Statistics reports that heavy and tractor-trailer drivers made median annual wages, as of May, 2014, of $39,520. Work for a general freight company and you may make a bit more: $41,690. These incomes put you above the national average of $35,540.

Truck Driving Training is a Call Away

Getting your CDL requires proper training, since you must actually drive a semi for the state licensing examiner to approve you. An excellent place to receive hands-on, rigorous training is at ATI, where you can earn your Tractor Trailer Driving Certification  in as little as eight weeks. You will learn many amazing and unbelievable facts in classes on vehicle systems, operating systems, documentation, road operations and more. Contact ATI today to learn how you can amaze your family and friends with the fact that you can become a professional truck driver.

I went through the tractor trailer school and a semester of heating and air conditioning and it was awareness I really learned a lot. I used the Gi bill from the Navy to goto school !!!

Posted by Steven Altman on Friday, August 21, 2015

Tractor-Trailer Truck Driving Training

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