How many questions are on the Delaware CDL knowledge test?

The Delaware CDL general knowledge test has 50 multiple-choice questions, and you need 80% (40 correct) to pass. The Doubles/Triples test is shorter. Most states do not publish its question count, but the 80% pass mark is federal under 49 CFR 383.135 and applies to every CDL knowledge test.

What's the minimum age for a CDL in Delaware?

In Delaware, the minimum age for a CDL is 18 (intrastate); 21 (interstate). Federal law requires drivers to be 21+ to drive a CMV across state lines or to transport hazardous materials, regardless of state minimum age.

Can I pull triples anywhere with this endorsement?

No. The T endorsement is what qualifies you, but whether triples may run at all is a state and highway decision, and many states do not permit them or restrict them to specific routes. Check the rules for every state on your route rather than assuming the endorsement travels with you.

What is rearward amplification?

Rearward amplification, also called the crack-the-whip effect, is the tendency for the last trailer in a set of doubles or triples to swing more than the trailers ahead of it during a sudden lane change or swerve. In triples, the last trailer can amplify a steering input by up to three times. This is why smooth, gradual steering is critical.

Are triple trailers legal in every state?

No. Triple trailers are only legal on certain designated routes in specific states. Many western states allow triples on interstate highways, but many eastern states do not permit them at all. Even where legal, triples are often restricted to specific roads and have speed limitations. Check your state's regulations before operating triples.

How should trailers be ordered in a doubles or triples combination?

The heaviest trailer should always be closest to the tractor (in the first position), and the lightest trailer should be at the rear. For triples, the second-heaviest goes in the middle. This arrangement minimizes rearward amplification and improves stability during braking and turning.

Do I need a Class A CDL for doubles/triples?

Yes. Doubles and triples are combination vehicles that exceed the weight ratings of Class B and Class C licenses. You must hold a Class A CDL to operate any double or triple trailer configuration. The T endorsement is added to your existing Class A CDL.

What is a converter dolly?

A converter dolly is a coupling device with one or two axles and a fifth-wheel that is used to connect a trailer to the rear of another trailer or to the tractor. It converts a semi-trailer into a full trailer that can be towed behind another trailer. Proper inspection of the dolly's coupling, air lines, light connections, and safety chains is critical for safe doubles/triples operation.

Delaware CDL doubles/triples practice test

Updated for 2026 · 45 doubles/triples questions of 483 across the full DE CDL path · Aligned to the commercial driver manual · Part of the DE CDL path

Start with general knowledge first. We recommend completing it before drilling doubles/triples questions.

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Required to pull two or three trailers. Covers coupling order, the converter dolly, and why the rear trailer swings hardest in a crack-the-whip.

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About the Delaware Doubles/Triples test

A separate written exam at the federal 80% pass mark. Most states do not publish a question count for it, and passing it qualifies you without making triples legal on every route. Questions cover coupling and uncoupling procedures for double and triple trailers, rearward amplification (crack-the-whip effect), inspection of multiple trailers and their connections, proper trailer order (heaviest trailer closest to the cab), rollover risks, braking distances for longer combinations, and the specific handling differences between doubles and triples. This is a separate knowledge test from General Knowledge, required in every state under 49 CFR 383.71, and the DMV publishes the Delaware Commercial Driver License Manual as the study source for it.