CDL Doubles and Triples Practice Test

Question 1

What is the maximum legal length of a doubles combination in most states?

Accepted Answer

65 feet

Answer

53 feet

Answer

75 feet

Answer

80 feet

Question 2

When coupling a second trailer to form a doubles combination, the converter dolly should be:

Accepted Answer

Aligned under the front of the second trailer with the kingpin locked

Answer

Placed at the rear of the first trailer only

Answer

Attached directly to the cab's fifth wheel

Answer

Positioned at the midpoint of the second trailer

Question 3

What is 'crack the whip' and why is it more dangerous with doubles/triples?

Accepted Answer

Rear trailer amplification where each unit swings more violently during maneuvers, increasing rollover risk

Answer

A technique for backing doubles into tight spaces

Answer

The sound made by improperly connected air lines

Answer

A method of braking doubles on downhill grades

Question 4

Before operating doubles/triples, you should check that all trailer air connections are:

Accepted Answer

Properly coupled, not leaking, and connected to the correct lines

Answer

Only connected if the trip exceeds 100 miles

Answer

Checked only by the dispatch facility before departure

Answer

Connected in any order as they are interchangeable

Question 5

When should the converter dolly's safety chains be used?

Accepted Answer

Always — they must be connected whenever the dolly is coupled to a trailer

Answer

Only when carrying hazardous materials

Answer

Only on highways, not local roads

Answer

Only when the load exceeds 40,000 lbs

Question 6

What is the MOST important factor in preventing a doubles/triples rollover?

Accepted Answer

Reducing speed before curves and turns

Answer

Keeping the fuel tanks full for stability

Answer

Driving in the right lane at all times

Answer

Avoiding routes with any curves