All About the Doubles/Triples Endorsement

When you take your commercial driver’s license (CDL) written test, you will also have the opportunity to take endorsement tests. If you pass, you will earn additional certifications that allow you to drive different types of vehicles beyond a standard semi-truck, or to haul different types of freight. 

One of these endorsements is the doubles/triples endorsement, which allows you to drive a commercial vehicle with more than one trailer. Such vehicles can also be referred to as long combination vehicles (LCVs).

Here’s more information about the LCV endorsement:

Why Earn the LCV Endorsement

Semi-trucks with two or three trailers can transport more freight at once. This means that trucking companies are able to pay more for drivers who drive these vehicles. Although you may think you’ll never need to want to use a doubles/triples endorsement in your trucking career, it’s still beneficial because it opens up more job opportunities if you ever wish to explore them.

How to Earn the Doubles/Triples Endorsement

Earning the LCV endorsement requires you to pass a multiple-choice written exam which covers material from Section 7 of the CDL manual. This section contains multiple subsections that you can study to help you prepare.

These are:

Pulling Multiple Trailers

There are various concerns you’ll need to be aware of if you are pulling two or three trailers. Some of these include preventing roll-overs and additional precautions you’ll need to take if there are adverse driving conditions. Vehicles with double or triple trailers also take up more space than other types of commercial vehicles, which presents additional challenges for space management and for parking.

Coupling and Uncoupling

It’s important to know how to couple and uncouple trailers correctly for any type of combination vehicle. When there are twin or triple trailers involved, this becomes more complicated. This section gives step-by-step instructions for how to do this, but you should keep in mind that it doesn’t cover every possible combination and that more on-the-job training may be necessary.

Inspecting LCVs

Vehicles with two or three trailers have more parts to inspect compared to a standard semi-truck. It’s important to fully expect every trailer and the coupling system and to know what additional parts to be aware of.

Air Brakes

Before hitting the road in a vehicle with an air brake system, you’ll need to perform an air brake inspection. For doubles/triples, you’ll need to ensure the air goes to all trailers, and will also need to test the service brakes, emergency brakes, and trailer protection valve.

Earn Your Doubles/Triples Endorsement

At Yuma Truck Driving School, we can help you earn your CDL and three endorsements (hazard materials, tanker, and doubles/triples) in as little as four weeks. Our experienced instructors will teach you the skills you need to succeed as a truck driver.

To learn more about earning your CDL in Yuma, AZ, contact us today.


Understanding the Hazmat Endorsement

Earning your commercial driver’s license (CDL) is the first step toward becoming a truck driver. For certain vehicles or types of freight, you will need more than just the standard commercial license. Endorsements are additional certifications that you can earn by passing written exams. At Yuma Truck Driving School, we help our students earn three endorsements: hazardous materials (hazmat), tanker, and doubles/triples. The hazmat endorsement allows you to transport sensitive freight and can increase your earning potential.

More information about the CDL hazmat endorsement:

X Endorsement

One thing to be aware of is that hazmat is often in a liquid or gaseous form and needs to be transported using a tank vehicle. As a result, you will also need the tanker endorsement for many hazmat jobs. The combination of these two is known as the “X” endorsement. Our program allows you to earn both.

Studying for the Hazmat CDL Test

To prepare for the written hazmat test, you should read Section 9 of the CDL manual. This covers the material that you will need to know to answer the multiple-choice questions on exam day. It is broken down into several subsections.

Keep in mind, however, that the manual does not necessarily cover everything you will need to know on the job. If you choose to pursue a career as a hazmat trucker, you may need additional training from your employer and should always prioritize safety.

The subsections you will need to study for the CDL hazmat test are:

The Intent of the Regulations

Hazmat regulations are intended to contain the material, communicate the risk, and assure safe drivers and equipment. You should know how these regulations accomplish those three goals.

Who Does What

The shipper, the carrier, and the driver all have specific responsibilities when transporting hazmat. You will need to know what these are.

Communication Rules

If there is an accident involving hazmat, the driver may not be able to communicate the hazards of the material they are transporting. To make it easier for emergency response personnel to identify and address any spills or accidents, hazmat must be properly labeled. You will need to know the different hazmat classes, placard requirements, and shipping paper requirements.

Loading and Unloading

You need to be cautious when loading and unloading hazmat. This subsection of the CDL manual goes over specific regulations based on the material’s class as well as general rules to follow.

Bulk Packaging, Marking, Loading, and Unloading

There are additional requirements for bulk packaging that you need to be aware of and follow.

Driving and Parking Rules

Certain classes of hazmat have restrictions for parking and driving that you’ll need to be aware of. Route restrictions can also vary by state and county, so if you take a job hauling hazmat, you’ll need to ask your dispatcher about these requirements for the specific route you are taking.


This subsection includes general guidance for handling emergencies that could arise when transporting hazmat. It also gives more specific information based on material class.

Earn Your CDL and Hazmat Endorsement

The hazmat section of the CDL manual can be confusing, and you may find it difficult to study for the written exam on your own. Yuma Truck Driving School can help. Our program covers the information you need to know to earn your CDL with the hazmat endorsement, as well as endorsements for tankers and doubles/triples. We can help you get on the road and earning in as little as four weeks.

Contact us today to learn more about earning your CDL in Yuma, AZ.