Your Guide to CDL Endorsements

Obtaining a commercial driver’s license (CDL) is your first step to a high-paying career as a truck driver. This license requires you to pass a written permit test and a hands-on skills test in order to demonstrate your ability to drive a commercial motor vehicle. In addition to the basic knowledge and skills tests, you can also add endorsements. These additional certifications show that you have learned safety and operational skills beyond the standard CDL requirements. At Phoenix Truck Driving School, we help you earn three CDL endorsements: Tanks, Doubles/Triples, and Hazardous Materials.


This is known either as the Tanks or Tanker endorsement. It demonstrates that the CDL holder has the knowledge required to operate a vehicle including a tank that transports liquid or gaseous materials. Tanker trucks transport fuel to gas stations across the nation. They can also transport any type of liquid from water to industrial chemicals. Due to the high demand for tanker drivers, a CDL tanker endorsement may help you land a truck driving job more quickly. The tanker test will cover basic safety regulations for transporting liquids in a commercial motor vehicle (CMV). The test will require you to understand what exactly a tank is and how it differs from other types of vehicles. One big safety issue you will be tested on is surge, which is how liquids move during transport. Your instructors at Phoenix Truck Driving School will help you thoroughly prepare for any questions on your tanker endorsement test.


A standard semi-truck will only carry one trailer. However, some trucks can include two or three attached trailers in order to transport more cargo. These are known as doubles and triples or Longer Combination Vehicles (LCVs). Driving a LCV requires an additional CDL endorsement. Your CDL test for the doubles and triples endorsement covers basic knowledge you need to safely operate a LCV. This includes understanding how to attach multiple trailers, how to drive a LCV around other motorists, and rules for double/triple inspection. Adding a Doubles and Triples endorsement to your Class A CDL allows you to operate these higher-capacity vehicles, allowing you to potentially earn more as a truck driver. Our classes at Phoenix Truck Driving School cover all the information you need to pass the additional knowledge test for this endorsement.

Hazardous Materials

Semi-trucks can transport a wide variety of goods and this can include hazardous materials. A hazardous material (or hazmat) endorsement for your CDL allows you to transport substances that the Department of Transportation labels as potentially harmful to human health. Drivers who obtain a CDL endorsement for hazmat can earn more per mile than other truck drivers. This endorsement has a slightly different process, as the Department of Transportation requires a full background check for any truck driver looking to add a hazmat endorsement. Certain criminal offenses can disqualify you. Our team at Phoenix Truck Driving School can go over these in detail with you to determine whether or not you qualify.

Earn Your CDL and Endorsements

Complete your CDL training at Phoenix Truck Driving School to earn your license as well as these three endorsements. We do all that we can to help our students succeed as truck drivers. This includes providing additional training to set you apart from other recent CDL graduates. Call us today to learn more about our training programs.

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