5 Must-Have Features in a Semi Truck Trailer Types

Author: Fayella

Jun. 23, 2025

Transportation

Top 17 Semi Trailer Facts You Should Know: Ultimate Guide For

Introduction to Semi Trailers

Semi trailers are essential to the global transportation industry. These non-powered vehicles attach to trucks and help move everything from groceries to heavy machinery across long distances. The concept dates back to the early 20th century, when freight hauling needed a more flexible solution than boxcars and wagons.

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Over the years, semi trailers have evolved with technological innovations, becoming more durable, efficient, and specialized for different industries. Today, they’re the lifeblood of logistics, responsible for hauling over 70% of goods in the United States alone.

Different Types of Semi Trailers

Semi trailers come in various designs, each tailored to specific cargo types:

Dry Van Trailers

These are enclosed and versatile, perfect for general freight like packaged goods or electronics.

Flatbed Trailers

Open-deck trailers suited for oversized loads such as machinery or construction materials.

Refrigerated (Reefer) Trailers

Insulated and temperature-controlled units for perishable goods like food or pharmaceuticals.

Tanker Trailers

Designed to carry liquids—fuel, milk, chemicals—often with special linings for safety.

Lowboy and Double Drop Trailers

Ideal for transporting tall, heavy equipment. Their low deck height allows clearance under bridges.

How Semi Trailers Work

A semi trailer connects to a tractor unit using a fifth wheel coupling system, allowing it to pivot during turns. Air brakes, powered by the truck, stop the trailer. Lights, indicators, and other functions are powered via an electric cable connected to the truck’s system.

These trailers lack a front axle and rely entirely on the tractor for movement and steering, which gives them their "semi" designation.

Common Uses and Applications

Semi trailers are incredibly versatile. Here's where you’ll see them most:

  • Logistics & Freight: Transporting goods for retailers and manufacturers.

  • Construction: Carrying heavy machinery, steel, and concrete.

  • Agriculture: Moving livestock, grain, or farm equipment.

  • Oil & Gas: Hauling chemicals and drilling gear.

Key Components of a Semi Trailer

Every semi trailer has vital parts that keep it operational:

  • Axles and Suspension Systems: Support heavy loads and provide stability.

  • Flooring and Side Panels: Usually made of aluminum, wood, or composite for strength.

  • Electrical and Lighting Systems: Required for legal operation, especially at night.

Popular Semi Trailer Brands

Some of the top brands that dominate the semi trailer market include:

  • Great Dane

  • Utility Trailer Manufacturing

  • Wabash National

  • Fontaine

  • MAC Trailers

These companies are known for innovation, durability, and a wide selection of trailer types.

Key Components of a Semi Trailer

Understanding the main parts of a semi trailer helps ensure proper usage, maintenance, and safety.

Chassis

The chassis is the base frame that supports the entire structure. It provides rigidity and strength and is usually made from high-tensile steel or aluminum to handle heavy loads.

Axles and Wheels

Most semi trailers have two or three axles at the rear. These axles support the trailer's load and allow for smooth transportation. Wheels are fitted with heavy-duty tires to endure long hauls and varied terrains.

Suspension Systems

Suspension systems—either air-ride or spring—absorb shock and keep the cargo stable during transport. Air-ride systems are common for fragile or sensitive loads due to their smoother ride.

Braking System

Modern semi trailers use air brakes, which are powerful and reliable. These brakes are essential for maintaining control, especially when carrying heavy loads down slopes or in traffic.

Trailer Coupling and Kingpin

The kingpin is the pivot point on the trailer that connects to the fifth wheel of the tractor. This coupling is critical for safe towing and maneuverability.

Advantages of Using a Semi Trailer for Freight

There are many reasons businesses prefer semi trailers for their logistics needs.

High Payload Capacity

Semi trailers can carry up to 80,000 pounds (with proper permits), making them ideal for bulk transportation.

Cost-Effectiveness

Due to their large load capacity, businesses save on fuel, labor, and trips. One semi trailer can do the work of multiple smaller trucks.

Versatility Across Industries

From agriculture to retail to construction, semi trailers adapt to many cargo types. Custom trailer builds also allow for specialized transportation.

Common Industries That Rely on Semi Trailers

Semi trailers are essential in multiple sectors:

Logistics and Freight

Companies like FedEx, UPS, and DHL use semi trailers to move goods efficiently across long distances.

Agriculture and Farming

Farmers use flatbeds and refrigerated trailers to transport produce, grain, and livestock.

Construction and Heavy Equipment

Lowboys and drop deck trailers carry bulldozers, excavators, and building materials to job sites.

Licensing and Legal Requirements

Operating a semi trailer involves legal and regulatory considerations.

Commercial Driver’s License (CDL)

Drivers must have a valid CDL, often with additional endorsements for hazardous materials or double trailers.

DOT Regulations and Compliance

The U.S. Department of Transportation requires regular vehicle inspections, hours-of-service tracking, and safety protocols.

Weight Limits and Axle Configurations

Weight distribution is crucial to avoid fines or accidents. The Federal Bridge Formula dictates how much weight each axle can legally bear.

Maintenance Tips for Long-Lasting Semi Trailers

Regular upkeep prevents breakdowns and extends trailer lifespan.

Routine Inspection Checklist

Check the tires, brakes, lights, and connections before every trip.

Tire and Brake Maintenance

Ensure proper inflation and tread depth. Brake pads and drums should be inspected frequently for wear.

Electrical and Lighting Systems

Working lights and signals are essential for safety and legal compliance.

Safety Features and Innovations

Safety technologies continue to evolve in the semi trailer industry.

Anti-lock Braking Systems (ABS)

ABS prevents wheels from locking up during braking, reducing skidding and maintaining control.

Electronic Logging Devices (ELD)

These track driving hours and promote safer, more compliant trucking operations.

Rear and Side Underride Guards

These guards help prevent smaller vehicles from sliding under the trailer in a crash, significantly reducing fatal accidents.

Environmental Impact and Green Solutions

As environmental concerns grow, the industry is adopting greener practices.

Fuel Efficiency and Aerodynamics

Skirts, tails, and wheel covers improve airflow and reduce drag, saving fuel.

Electric and Hybrid Trailer Options

New models feature electric refrigeration units and regenerative braking to reduce emissions.

Regulatory Trends on Emissions

Agencies like the EPA and CARB are pushing for cleaner trucks through emissions standards and incentive programs.

Cost Breakdown and Financing Options

Purchasing a semi trailer is a major investment.

New vs Used Semi Trailers

New trailers offer warranty and latest tech, while used trailers are budget-friendly but may need repairs.

Leasing vs Buying

Leasing provides flexibility and lower upfront costs; buying builds equity and long-term savings.

Insurance and Maintenance Costs

Expect to pay for liability insurance, cargo coverage, and regular upkeep. These are ongoing costs to budget for.

Choosing the Right Semi Trailer for Your Business

Finding the right trailer involves analyzing your specific needs.

Factors to Consider

Load type, frequency of use, distance traveled, and legal requirements all affect your decision.

Customization Options

From lift gates to temperature control, semi trailers can be tailored to fit niche uses.

Best Brands in the Market

Well-known manufacturers include Great Dane, Utility, Wabash, and Fontaine, all known for reliability and innovation.

Future Trends in the Semi Trailer Industry

Exciting advancements are shaping the future of freight.

Smart Trailers and IoT

Sensors now track load weight, temperature, tire pressure, and location in real time.

Autonomous Trucking

While still in testing, driverless trucks are expected to revolutionize the supply chain in the next decade.

Regulatory and Market Shifts

New emissions laws, electric infrastructure, and e-commerce growth are influencing trailer design and operations.

Frequently Asked Questions (FAQs)

1. What is the difference between a semi trailer and a full trailer?
A semi trailer lacks a front axle and relies on the tractor for support, while a full trailer has axles at both ends and can stand alone.

2. How long is a standard semi trailer?
Most standard trailers are 53 feet long, though shorter lengths (28, 40, 48 feet) are also common.

3. What type of license is needed to drive a semi trailer?
You need a Commercial Driver’s License (CDL), often with endorsements for special cargo types.

4. How much weight can a semi trailer legally carry?
Typically up to 80,000 pounds gross vehicle weight without special permits.

5. How often should a semi trailer be inspected?
A pre-trip inspection is required daily, with more thorough inspections recommended every 3-6 months.

6. Are electric semi trailers available?
Electric models are emerging with features like battery-powered refrigeration and regenerative braking.

Conclusion

Semi trailers are more than just giant cargo carriers—they're the backbone of global trade and logistics. From hauling goods to powering industries, their design and versatility make them indispensable. With evolving technologies, regulatory updates, and sustainable practices, the semi trailer industry is well on its way to an even more efficient future.

The 11 Most Common Trailer Types Used in The Trucking Industry ...

  • Dry Van Trailers
  • Standard Flatbed Trailers
  • Refrigerated Trailers (Reefers)
  • Drop-Deck/Step-Deck Trailers
  • Double Drop/Lowboy Trailers
  • Hotshot Trailers
  • Conestoga Trailers
  • Curtainside Trailers
  • Extendable Drop-Deck Trailers
  • Standard RGN Trailers
  • Extendable RGN Trailers

With so many different trailers on the roads today, it can be difficult to discern what each is used for and which is best for your freight.

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Having been in business since , here at Anderson Trucking Service (ATS), we’ve seen trailers evolve and helped customers select the best type for them. In fact, we’ve worked directly with the leading trailer manufacturers to create several of the trailers you see going down the road today.

In this article, we’ll break down the most common trailers found in America’s trucking landscape in and how each is used. This will leave you with a better understanding of which trailer type best fits your needs.  

Dry Van Trailers

When it comes to the shipment of pallet-based, boxed or loose commodities, dry van trailers are the go-to solution. Typically measuring in at 53 feet, the dry van trailer is the most common type of trailer on the roads today.  

For the most part, dry van trailers are used to ship the items people use every single day.

Some of the world’s largest corporations, including Walmart, Target and Procter & Gamble, use dry van trailers to transport their inventories. Inventories such as clothing, non-perishable food items and household goods are commonly transported using dry van trailers. 

Because of their boxlike shape and ability to back right into the bay of a loading dock, these trailers are the ideal equipment type for any shipper/receiver working from a loading dock. 

Characterized by their enclosed container used to keep materials safe, these trailers have a maximum weight range of 42,000-45,000 pounds. Because of the encasement of the cargo inside and the inability of their floors to support a lot of weight, these trailers are not suited to carrying oversized loads (unlike a flatbed). 

That said, dry van trailers are a versatile, affordable shipping solution. 

Dry vans typically have a lower cost per mile (CPM) than open-deck trailers (meaning they cost less to ship with).

The main constraint to consider when booking a dry van trailer is whether or not your cargo will fit within the trailer’s fixed dimensions — the walls and ceiling. Since these trailers are enclosed, shippers should verify the dimensions of their cargo to ensure everything will fit within it. 

Fast Facts:

  • Dry vans made up 61 percent of the trailers produced by U.S. manufacturers in (According to ACT Research)
  • Typically either 48 or 53 feet long. 
  • Max width: 101 inches
  • Max height: 110 inches
  • Maximum weight: 42,000-45,000 pounds. 
  • Ideal for loading/unloading using a loading dock. 
  • Often privately owned and branded. 

Related: How Many Pallets Fit in a 53-Foot Dry Van Trailer?

Standard Flatbed Trailers

In addition to the dry van, the standard flatbed trailer is an incredibly common type of trailer. Although they come in several different sizes (including 24, 40, 45, 48 and 53 feet) the 48-foot flatbed trailer is the most frequently used. 

Versatility is a key feature of these trailers. Often used to haul steel, construction equipment, lumber and other open-air commodities, the flatbed’s open back and sides make for easy loading and unloading via forklift or overhead crane. 

The maximum height and width of any freight transported using these trailers is 8 feet, 6 inches. The flatbed trailer rests 5 feet off the ground and can haul a maximum capacity of 48,000 pounds. 

Because it doesn’t have a container to house its contents (like a dry van), the flatbed trailer can be used to haul oversize freight as long as the necessary permits are acquired and the proper routes are followed.

The securement of freight on standard flatbed trailers — and all others — must be done properly using chains, straps and various tarping solutions.

Since Flatbeds are not enclosed trailers, the cargo they haul is exposed to elements, like the weather outside. Because of this, most flatbed drivers will carry highly-durable tarps to cover the cargo and provide additional protection from things like rain and snow.

Fast facts:

  • Standard flatbeds comprised nine percent of the total trailers produced in the U.S. in
  • Can haul oversize freight with proper permitting. 
  • Available in 24, 40, 45, 48 and 53 feet (48-foot is most common). 
  • Load/unload from the back, side or above: loading dock, forklift or overhead crane. 
  • Maximum freight height and width: 8 feet, 6 inches. 
  • Maximum weight capacity: 48,000 pounds. 

Related: Common Flatbed Trailers [Alternatives and Differences]

Refrigerated Trailers (Reefers)

Just as the name suggests, refrigerated trailers (also called reefers) were designed to move any freight requiring temperature control. Their temperature control and insulated walls make them the only type of trailer that is properly suited to haul perishable items. Products like fruit, pharmaceuticals and ice cream are commonly moved using these trailers. Depending on the cargo-type hauled, drivers pulling refrigerated trailers may need to follow regulations like the Food Safety Modernization Act (FSMA) or those related to moving hazardous cargo.

Refrigerated trailers boast a maximum weight capacity that mirrors dry vans (42,000-45,000 pounds). 

It should be noted that — due to their insulated walls — the maximum height a reefer can haul ranges between 8 feet and 8 feet, 2 inches while the maximum width is 8 feet, 2 inches.

Like the dry van, reefers cannot haul any commodity that exceeds the length of their deck.   

When needed, the temperature control system of a reefer can be turned off, and the trailer can be used like a (slightly smaller) dry van. This can help to expand your capacity reach when shipping products not requiring temperature control. 

Refrigerated shipping rates can vary greatly depending on your company’s location and the time of year. 

Fast Facts:

  • Reefers made up about 15 percent of trailer production in
  • Primarily used for temperature-sensitive cargo
  • Maximum weight capacity: 42,000-45,000 pounds
  • Maximum height: 8 feet to 8 feet, 2 inches
  • Maximum width: 8 feet, 2 inches

Drop-Deck/Step-Deck Trailers

Drop-deck or step-deck trailers are commonly used as an alternative to the flatbed trailer when the height of a load is a factor. They are essentially the same as a flatbed, with the benefit of allowing additional cargo height from their lower deck. The simplicity of a flat trailer deck coupled with added height capacity makes the drop-deck trailer a commonly utilized method of transport. 

Comprised of an upper deck and a close-to-the-ground rear section, drop deck trailers can typically haul loads of up to 10 feet, 2 inches in height before being considered over-dimensional (maximum legal loaded height varies by state).

Where flatbeds are typically 5 feet off the ground, drop-deck trailers are much shorter, measuring 3 feet, 6 inches at their lowest point. If 53-feet long, the lengths of the upper and lower decks of this trailer are 10 feet and 43 feet respectively. 

Because of their versatility and ability to carry taller loads, step deck trailers are a widely popular option among carriers spanning the globe. You’ll commonly see these trailers hauling agricultural machinery and construction equipment. 

Fast Facts:

  • One of the most common alternatives to a traditional flatbed trailer
  • Maximum freight height (without low-profile tires: 10-11 feet (depending on location)
  • Typically 53-feet long: 10-foot upper deck, 43-foot lower deck
  • Maximum weight capacity: Around 46,000 pounds
  • Can be permitted for oversize loads

Double Drop/Lowboy Trailers

Also known as lowboy, the double drop trailer is far closer to the ground than most other trailer types. Its proximity to the ground is thanks to two drops that occur behind the gooseneck and before the back wheels. As such, double-drop trailers can carry tall pieces of freight.

Double-drop trailers are typically heavier than step-decks and flatbeds. This limits the maximum weight of the cargo they can legally haul. Usually, double-drop trailers can haul up to 38,000 pounds of cargo before possibly requiring permits for weight. These trailers can be used for heavier shipments, but it's important to note that weight can only be permitted for single-piece freight shipments. 

A double-drop trailer's length-of-load capacity is limited to its well space which varies but typically measures around 29 feet long. 

The maximum legal height of any freight carried by a double drop trailer is 11 feet, 6 inches before being considered over-dimensional. This advanced height capacity makes them the perfect solution for any company hauling large freight or cargo exceeding legal height limits on flatbeds of step-decks.

Examples of these include industrial and farm equipment/machinery that needs to be moved to/from a job site. 

Fast Facts:

  • Maximum legal cargo weight limit: around 38,000 pounds
  • Maximum length: Limited by well space, typically 29 feet. 
  • Maximum legal freight height: 11 feet, 6 inches-12 feet, 6 inches (depending on location)

Hot Shot Trailers

Hot shot trailers are low-lying flatbed trailers that can be pulled with a class 3-6 pickup truck. As such, carriers using hot shot trailers do not need to own a traditional semi-tractor since they can be pulled using a specialized pickup truck. This removes a lot of the trucking industry's barriers to entry from this process. 

Hot shot trailers provide a far more cost-effective way to haul freight, especially for short distances, than a traditional flatbed trailer. Companies that specialize in shorter lengths of haul have been using these hot shot trailers with great success. 

In terms of size, most hot shot trailers on the market measure 30-40 feet long and rest between 3 feet, 4 inches and 3 feet, 6 inches above the ground. Because these trailers are so much smaller than the other options, the overall weight they can carry suffers. A 40-foot hot shot trailer can typically haul no more than 16,500 pounds of freight, sometimes less. 

What hot shot trailers give up in carrying capacity they make up for in convenience and cost-efficiency. This makes them a great alternative for companies who need to haul freight that would otherwise result in LTL capacities on larger trailers. 

Fast Facts:

  • Do not require a traditional semi-tractor
  • Most 30-40 feet long
  • Maximum freight height: 9 feet, 6 inches to 10 feet (varies by location)
  • Between 3 feet, 4 inches and 3 feet, 6 inches above the ground
  • Maximum weight: no more than 16,500 pounds

Conestoga Trailers

Conestoga trailers are a specialized trailer type designed as an additional option for freight that requires in-transit protection from the elements. Conestogas feature a fixed rail/canopy system that can pulled back for loading and pulled forward to cover freight during transport. 

This system is especially beneficial for cargo that would be damaged by traditional tarping and for freight with sharp edges that could, potentially, shred a driver's tarps.

Typically measuring 53-/48-feet long, Conestoga trailers are a great alternative to many open-deck trailers as they commonly come in step-deck, double-drop and flatbed iterations.

Though Conestoga's are used in a number of industries — to transport freight of all types — industries with sensitive cargo, which could be damaged by tarping it, such as the aerospace and energy sectors utilize them most frequently. 

Conestogas are a relatively specialized type of trailer, making them more expensive to use than other open-deck trailers in some scenerios. However, Conestogas are a great alternative to tarping and are becoming increasingly common. 

Fast Facts:

  • Typically 53 feet long
  • Available in step-deck, double-drop and standard flatbed configurations
  • Features a fixed-rail, sliding-canopy system
  • Used for freight requiring protection from the elements
  • Maximum weight: 42,000-45,000 pounds

Related: What is a Conestoga Trailer?

Curtainside Trailers

Curtainside trailers are similar to Conestoga trailers in that they both feature built-in tarp systems. Cutrainsides have a solid top, rear, and front, and hanging tarps on each side. As such, these trailers can only be loaded from the back or sides and not from above (unlike a Conestoga). 

Curtainsides are an excellent option for moving freight that requires protection from the elements in transit as its tarps create a seamless barrier to keep cargo from interacting with wind, rain, dirt and debris. Curtainsides are typically 48- to 53-feet long, with a maximum cargo capacity of 40,000-43,000 pounds. 

Fast Facts:

  • Alternative to dry van and Conestoga trailers
  • Usually 48- or 53-feet long
  • Maximum cargo weight: 40,000-43,000 pounds
  • Solid top, rear, front with a hanging tarp on each side
  • Loaded from the back or sides, not from above

Related: What is a Curtainside Trailer? [Definition, Pros and Cons of Using One]

Extendable Drop-Deck Trailers

These trailers are used to haul exceptionally long freight. To do this, the middle portion of these trailers can be extended from an original length of 38 feet to a maxed-out length of 65 feet. This makes extendable drop-decks perfect for hauling freight that exceeds the legal length limits of traditionally-sized trailers. 

The maximum capacity of these trailers is 43,000 pounds and, much like the standard drop deck trailer, this trailer can accommodate a maximum legal height of 10 feet, 2 inches.

Commonly used to transport large machinery and extra-long raw materials, these trailers are very useful for shipments exceeding 38-feet long and between 8 feet, 6 inches and 10 feet, 2 inches in height (location depending). 

Fast Facts:

  • Middle portion extends from 38-feet to 65 feet
  • Maximum weight capacity: 43,000 pounds
  • Maximum legal cargo height capacity: 10-11 feet (depending on location)

Removable Gooseneck Trailers (RGN)

These trailers, which come in a variety of sizes, can be used in a lot of the same ways as traditional trailers. In an industry that houses a wide variety of options for shippers to choose from, RGNs are certainly worth consideration. 

As the name suggests, the gooseneck — used to secure the trailer to the tractor — at the front of these trailers can be removed. By doing so, the driver places the front of the trailer on the ground. This creates a ramp for loading and unloading equipment, making RGN trailers the perfect tool for hauling large, self-propelled machinery and equipment. 

Like traditional trailers, removable gooseneck trailers come in several sizes.

Standard RGN

The most commonly used member of the RGN family, the standard RGN can have two or three axles, depending on cargo weight. RGNs are typically used when height is a factor as they allow cargo up to 11 feet, 6 inches in height. 

RGNs provide ease of use for hauling large equipment; simply drive the equipment onto the trailer before its departure, safely secure it and drive it off at its destination.

This removes the need to have cranes and forklifts on site for the loading/unloading process. 

Standard RGNs are used in a lot of the same ways as double-drop trailers — they have the same weight and height restrictions. 

Like the double-drop trailer, the amount of well-space needed is a prime factor in whether these trailers are used. Any time a load exceeds 30 feet in length, the space provided by the wells of these trailers becomes insufficient. 

Fast Facts:

  • Available with two or three axles
  • Maximum legal cargo weight: 38,000 pounds
  • Maximum permitted cargo weight: 55,000-65,000 pounds
  • Maximum length: Limited by well-space, typically 30 feet 
  • Maximum legal height: Up to 11 feet, 6 inches (depending on location)

Extendable RGN

When well-space is an issue, the extendable RGN provides a solution. Similar to the expandable double drop trailer, the expandable RGN is built for extra-long freight.

With the capability to expand its well up to 50-feet long, these trailers provide ample capacity to haul large equipment, materials and oversize cargo. 

Depending on the number of axles, the weight capacity of these trailers can vary substantially.

The weight range for an expandable RGN trailer is 38,000 pounds (2-3 axles) to 225,000 pounds (19 total axles). 

Fast Facts:

  • Maximum cargo length: 50-feet long
  • Maximum legal cargo weight: 38,000 pounds
  • Maximum permitted cargo weight: 225,000 pounds (depending on number of axles)
  • Maximum cargo height: Up to 11 feet, 6 inches (depending on location)

Find the Best Trailer For Your Freight

Now you have a better understanding of many of the trailer types available to you and what each is used for. Now is the time to weigh these options and pinpoint which you feel would best fit the needs of your freight. 

If you need to move perishable food and beverage items, a reefer is the correct trailer type for you. If you have palletized commodities, consider a dry van. When making this decision, it’s always best to keep capacity, budget and length of haul in mind.  

In the trucking industry, using the right trailer is key when it comes to safely and uneventfully moving cargo from origin to destination. 

Make sure to specify accurate information with your transportation provider, which will help them order the correct truck and trailer. Necessary information includes: 

If you want to learn more, please visit our website Semi Truck Trailer Types(nl,mn,pt).

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