Semi-trailer trucks are a type of heavy-duty truck and are categorised as class 7 and 8 vehicles. They are used extensively for hauling heavy loads in commercial sectors such as transportation, logistics, construction, mining, and more. 

Keep reading further to know more about semi-trailer trucks. 

Semi-trailer trucks are heavy-duty trucks with a gross vehicle weight of about 80,000 pounds and a payload capacity of 20,000 to 50,000 pounds. These trucks are also called eighteen-wheelers, articulated lorries, tractor-trailers, and much more

Some of the standard specifications of a semi-trailer truck include: 

• The wheels of semi-trailer trucks can be dismounted and readjusted to distribute the load.
• A semi-trailer truck has at least two axles with two tires on each side.
• The air brake System of a semi-trailer truck includes both the parking brake circuit and the trailer brake circuit.
• The bed of the semi-trailer truck can be left uncovered or covered depending on the goods transported.
• Semi-trailer trucks are usually 72 feet long, 13.5 feet tall, and 8.5 feet wide.

Some of the common types of semi-trailer trucks include:

1. Flatbed Trailer Trucks

Flatbed trailers are versatile, with an open rear flatbed deck on all sides. These trucks are used for transporting weighty goods that need to be lifted with a crane and allow easy loading and unloading of the materials. 

They have a payload capacity of 48,000 pounds and can carry various trailers, such as drop-deck trailers, lowboy trailers, and removable gooseneck trailers. 

2. Dry Van Trailer Trucks

Dry van trailer trucks are semi-trailer trucks that are enclosed or box-like. Covered on all sides, these trailer trucks transport building materials, non-perishable food products, and much more. Dry van trailers, which can hold 42,000 to 45,000 pounds, have variations, such as side kit trailers, Conestoga trailers, and more.

3. Tanker Trailer Trucks

Tanker trailers are cylindrical and mainly transport liquid materials like fuel, asphalt, chemicals, beverages, gases, etc. They have a maximum payload capacity of 80,000 pounds and are available in variations such as stainless steel, aluminium, and pneumatic.

4. Dump Trailer Trucks

Dump trailers have a hauling trailer at the rear that can be lifted with the hydraulics and unload the material at the specific spot. These trucks offer safe and efficient hauling of the dumping material and have a varied payload capacity. These dump trailer trucks carry gravel, sand, stone, trash, and dirt.  

Semi-trailer trucks have the following advantages over other types of heavy-duty trucks: 

• Semi-trailer trucks are used for road connectivity and transporting goods to remote areas.
• These trucks offer door-to-door services, as they can transport goods from the origin to the destination. 
• Semi-trailer trucks are more accessible to load and unload, which saves time and is a cost-effective alternative for transporting goods.
• Because they can carry goods long distances, semi-trailer trucks transport construction materials, furniture, food, electronics, pharmaceuticals, and much more.

Semi-trailer trucks have the following disadvantages: 

• Compared to other modes of transportation of goods, semi-trailer trucks have a limited storage capacity. 
• These trucks have a high operating cost and need to be more environmentally sustainable.
• Semi-trailer trucks are susceptible to delays due to weather conditions, traffic jams, etc.
• Due to their large body, it is challenging to navigate semi-trailer trucks.
• Poorly secured freight on semi-trailer trucks can be a safety threat to other drivers on the road. 

Semi-trailer trucks can easily carry a massive load and are versatile in hauling huge loads over a long distance. They are widely used in construction, mining, transportation, and more. Depending on the trailers attached to the tractor, semi-trailer trucks are available in variants that make them a necessity in primary operations.