# Combination

All applicants who are applying for a Class A CDL should be prepared to take the Combination test. This test covers information found in Section 6 of the Commercial Driver License..

All applicants who are applying for a Class A CDL should be prepared to take the Combination test. This test covers information found in Section 6 of the Commercial Driver License Manual. Section 6 provides the information needed to safely operate tractor-trailers, doubles, triples, and straight trucks with trailers. The test is made up of 20 multiple-choice questions, and applicants will need to correctly answer a minimum of 16 questions to pass. The Combination test is not a replacement for the Double/Triple endorsement test.

Number of Question
Passing Score

### 1. To prevent a rollover, cargo should be:

Explanation
Cargo weight should be evenly distributed within a trailer to reduce the risk of a rollover. Do not place too much weight on one side of a trailer.

### 2. When connecting a converter dolly to a second trailer, the trailer height should be ____ the center of the fifth wheel.

Explanation
When connecting a converter dolly to a second or third trailer, the trailer height should correct. It should be slightly lower than the center of the fifth wheel.

### 3. What happens when the wheels of a trailer lock up?

Explanation
A trailer tends to swing around, potentially resulting in a trailer jackknife, if its wheels lock up.

### 4. What is a bobtail tractor?

Explanation
Tractors without semi-trailers are referred to as bobtail tractors. Operating a bobtail tractor requires drivers to exercise caution.

### 5. When glad hands are coupled, the seals should be pressed together at an angle of:

Explanation
When coupling, be sure to couple the proper glad hands. When glad hands are connected, the seals should be pressed together at a 90-degree angle.

### 6. A combination vehicle has ____ air line(s).

Explanation
Every combination vehicle has two air lines: the service line and the emergency line.

### 7. The emergency air line supplies air to the:

Explanation
The emergency air line (also known as the supply line) has two functions. The first is to supply air to the trailer air tanks, and the second is to control the emergency brakes on combination vehicles.