What is a 18 wheeler?

An 18-wheeler is a large commercial truck that has 18 wheels. They are also known as semi-trucks, tractor-trailers, or semis. 18-wheelers are typically used to transport goods over long distances. They are often seen on highways and interstates.

The term "18-wheeler" comes from the fact that these trucks have 18 wheels. The wheels are arranged in three groups of six. The front group of six wheels is called the "steering axle." The middle group of six wheels is called the "drive axle." The rear group of six wheels is called the "tag axle."

18-wheelers are powered by large diesel engines. They can weigh up to 80,000 pounds when fully loaded. 18-wheelers can be up to 75 feet long and 14 feet high.

18-wheelers are a common sight on roads and highways. They play a vital role in the economy, transporting goods across the country.