Trailer Trivia - NTDA - National Trailer Dealers Association

Trailer Trivia

Who invented the first semi-trailer?

In 1898, Alexander Winton (a Scottish-American vehicle maker) in Cleveland, OH invented the first semi-truck as a solution to transport his cars to customers.

Charles Freuhauf, a German-American blacksmith, invented the first tractor trailer in 1914 because he needed a way to transport his boat.

How and when did semi-trailers increase in popularity?

The use of what became known as “tractor-trailers” increased dramatically during World War I, when the military found that they offered speed and flexibility not available with trains and horse-drawn trailers. This was especially true after inflated (pneumatic) tires were created, as they addressed concerns about the effects steel and solid rubber wheels were having on the dirt and gravel roads of the day.

In the 1930s, the expanding construction of paved roads made semis even more useful, and when the Interstate Highway System was developed in the 1950s and 1960s, the tractor-trailer became the cornerstone of the cargo transportation industry.

Which states in the U.S. have the most registered semi-trailers?

According to Statista, there are 15.5 million semis operating in the U.S., and one-third of them are registered in California, Florida, and Texas.

What percentage of good and services are transported on a semi-trailer?

More than 70%.

How much does a tractor-trailer weigh?

A tractor-trailer fully loaded can weigh up to 80,000 lbs. (or 40 tons). That is the legal weight limit in the U.S.

Some commercial vehicles can be a lot heavier, however, including the semi-trailers that are used for freight transportation in South Dakota. The state has no weight limit on its non-interstate roads, which means companies can attach pretty much as many trailers as they want to their trucks, so long as they get the proper license.

What have been the most popular trucking movies?

There was a time in America where semi-trucks were popular in movies. In the 1970s particularly, Smokey and the Bandit, Duel, White Line Fever and Convoy were all released.

Convoy was arguably the most popular and it was based on a song that has made it onto Rolling Stone’s Top 100 Country Songs of All Time.

How many miles do semi-trailers travel each year?

Making long-distance journeys on a weekly basis, semi-trailers travel an average of 140 billion miles per year across U.S. highways.

Why are they called semi-trailers?

A semi-trailer has that name because it doesn’t have a front axle, and therefore isn’t the same as a trailer, which does. In other words, semi-trailers only have wheels at one end and need to rest on the chassis of the cab unit at the other end before the truck can get underway.

Why do semi-trailers have mudflaps?

  • They keep from pouring sheets of rainwater over nearby passenger vehicles
  • They decrease the amount of drag a semi produces when moving at highway speed.


What is a kingpin?

The kingpin is a mechanism on a trailer that locks it to a road tractor. It is typically positioned between 18” to 48” from the trailer nose.

How much money is collected from our industry for the Highway Trust Fund?

Thirty-six percent of taxes and fees related to the Highway Trust Fund are funded by the purchase of commercial vehicles, even though commercial vehicles compose only 7% of the overall traffic on U.S. roads.

What percentage of the trucking industry is comprised by small trucking companies?


What percentage of truck drivers are women?


How much is the trucking industry predicted to grow in the next 10 years?