What different types of trailers do drivers pull?

CDL Training

Over-the-Road and local trucks carry many kinds of loads. To do this, they use a lot of different types of trailers that are designed for specific purposes. Some trailers can be used in many different ways, and some are for one type of hauling. Here is a look at a few different types used by trucking companies, as well as their dimensions and weight limits.

Types of Trailers

Dry Vans – These are also known as box trailers. They are the most plentiful type of trailer, so named because the freight contents are completely enclosed in a box-type container that keeps the freight dry. These range from 28-53 feet in length, 96 (8'0”) to 102 (8' 6”) inches in width, and 12'6” to 13'6” in height. They will have anywhere from 8 to 16 wheels.

One common variation of the dry van is the curtain side trailer. This type has Heavy duty fabric sides that can be rolled up or moved to the side to allow access to the contents from the side of the trailer, unlike the dry van which must be loaded and unloaded from the rear. It is often used for making multiple stops/deliveries, and having fabric sides makes it possible for fork lift operators to get the freight intended for them without requiring lots of shifting around of other deliveries.

Refrigerater Trailer - Another common variation of the dry van is the refrigerated, or “reefer” trailer. As the name says, this type of trailer has a refrigeration unit to keep perishable freight such as meat, vegetables, and fruit at a temperature that is adjustable to prevent food from spoiling during transportation.

Other than curtain side trailers, dry vans are typically loaded and unloaded from the rear. A driver for a Less Than Truckload (LTL) operator will be involved in a lot of shifting of freight in most cases. The driver will also need to have the skill to back up to a loading dock.

The major benefit of the dry van is the protection from weather that the load receives.

These three trailer types can be combined into tandem or triple combinations, as long as overall length and weight rules are observed. The Commercial Drivers License (CDL) requires a special endorsement for drivers of combination rigs.

Tanker Trailers – Tankers are usually used to haul liquids and gases, although certain types of tankers can be used to carry dry bulk freight such as grain. There is a tanker endorsement required for the holder of a CDL. Tankers are most commonly used for fuels like gasoline, heating oil, and propane, so a driver will be required to carry a Hazardous Material (Haz Mat) endorsement, which requires fingerprinting and criminal background checks, and the passing of additional tests to receive certification.

Liquid tankers can be challenging to drive, especially gasoline tankers that may carry several types of fuel in separate compartments in the tanker, causing weight to shift around as the liquid sloshes, or one compartment is emptied and alters the weight distribution of the load.

Flatbeds – This is just a dry van with no sides. They are commonly used to haul building materials that are off-loaded with forklifts, or large bulky items such as heavy construction equipment that won't fit in dry vans. In order to keep total height below 13'6” limit, the flatbed trailer will frequently be modified into a “lowboy” where otherwise a high load might exceed the limit. Flatbeds range from 26 to 48 feet in length, and can be combined like dry vans.

Driving a flatbed will generally be very labor intensive due to lots of strapping and tarping of loads.

Weight Limits

Right now, the maximum Gross Vehicle Weight (GVW) for truck and trailer combinations is 80,000 pounds.  This weight limit is strictly enforced for drivers and trucking companies.

A pilot project in Maine temporarily raised this to 100,000 pounds on certain Maine Interstates. Those in favor of the increase said that this would save time and fuel, increase safety, lower emissions, and lower costs for trucking companies and receivers and preserve and create jobs.

Those against the idea mostly argued that the increased weight would damage roads, and present more danger to other vehicles.

 

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