18wheeler

An 18-wheeler, also known as a semi-trailer truck or tractor-trailer, is a combination vehicle consisting of a prime mover (tractor unit) and one or more semi-trailers. The "18-wheeler" designation comes from the typical number of wheels found on such a configuration: two wheels on the tractor's steering axle, four wheels on its drive axles (two axles with dual wheels on each side), and ten wheels on the semi-trailer (two wheels on its front axle, and four wheels on each of its two rear axles). Variations in trailer configurations can lead to differing wheel counts.

These vehicles are primarily used for transporting large quantities of goods over long distances. The tractor unit provides the power to pull the trailer, which carries the cargo. Different types of semi-trailers exist to accommodate various types of freight, including dry vans for general goods, refrigerated trailers for perishable items, and flatbeds for oversized or heavy equipment.

Operating an 18-wheeler requires specialized skills and licensing. Drivers must undergo extensive training and pass rigorous tests to obtain a commercial driver's license (CDL). Due to their size and weight, 18-wheelers have specific regulations regarding speed, routes, and parking. They are a vital component of the global supply chain, enabling the efficient movement of goods across continents. The sheer volume of cargo they can carry makes them an economical choice for many industries.