The Mysterious 18 Wheelers: Why Semi-Trucks Have This Name
Have you ever heard the term '18 wheelers' and wondered where it comes from? Here's a deep dive into the origin of this peculiar nomenclature, comparing the American version to its counterparts in the UK and Australia.
The U.S. Standard and Terminology
Semi-trucks, often referred to as '18 wheelers,' are a common sight on American highways. These trucks typically consist of one part with a front end containing the engine and driver's cabin, which has ten wheels, and a cargo-carrying trailer with eight wheels. Each trailer includes four axles, each with two wheels. This setup allows for better weight distribution and stability when hauling heavy loads, which is crucial for long-haul trucking.
However, the term '18 wheelers' is not as universally applicable as it might seem. Not all semi-trucks have exactly 18 wheels; some can have more or fewer, depending on the design and the cargo requirements. In the U.S., with a standard configuration, 10 wheels on the tractor (the front part with the engine and cabin) plus 8 wheels on the trailer means a total of 18 wheels. But in some cases, this number can vary. For instance, models with additional wheels for better load distribution or to meet specific regulations might have more.
UK Terminology: Articulated Lorries or Artics
Across the pond, British drivers refer to these massive vehicles as 'articulated lorries' or simply 'artics.' Unlike their American counterparts, British lorries often have fewer wheels, typically 14. These lorries have 8 wheels on the unit (the part with the engine and cabin) and 6 wheels on the trailer. This difference in terminology highlights a divergence in regional trucking culture.
Furthermore, British lorries are classified based on their load-carrying capacity rather than the number of wheels. They are often referred to by the number of axles, which is a common metric in the UK. For example, a typical 44-tonne lorry might have 6 wheels (2 on the driver’s unit and 4 on the trailer).
Australian Standards: 22 Wheelers and Beyond
When it comes to truck design, Australia takes a notably different approach. Australian semi-trucks, or '22 wheelers,' typically have three axles in the trailer, adding an extra wheel to the cargo-carrying portion. This adds up to a total of 22 wheels, giving these trucks a distinct advantage for handling heavier loads. In Australia, the maximum weight for standard trucks is 42,500 kg, or approximately 93,500 lb. This is lower than the 80,000 lb standard in the U.S.
However, to compensate for the shorter length of trailers used in Australia, some trucks benefit from a Front Underrun Protection System (FUPS), which can add about 2,000 kg in load capacity. FUPS essentially provides a heavy low front bumper that helps prevent the truck from riding up over a smaller vehicle in the event of a collision, especially when the trailer is longer than usual.
Conclusion
The term '18 wheelers' in the U.S. is a unique identifier for a specific semi-truck configuration that is not found in the UK or Australia. It represents a combination of ten wheels on the tractor and eight wheels on the trailer, each axle bearing two wheels. This design provides the necessary stability and weight distribution for long-haul trucking. However, the use of the term can be misleading, as some trucks might not conform to this exact specification. In regions like the UK, the classification is based on the number of axles, and in Australia, the configuration is such that trucks are often called '22 wheelers' due to the additional axle in the trailer.
Understanding these distinctions can help in better comprehending the world of trucking and how it varies across different countries and cultures.