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200+ Free Iowa CDL Combination Vehicles Test Practice Questions

Pass your Iowa Commercial Driver License Combination Vehicles Test exam on the first try — instant access, no signup required.

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Question 1
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On newer vehicles, the trailer air supply control is usually:

A
B
C
D
to track
2026 Statistics

Key Facts: Iowa CDL Combination Vehicles Test Exam

20/04

Iowa Combination Vehicle questions/allowed misses

Iowa DOT CDL Testing

80%

Minimum passing score for CDL knowledge tests

FMCSA / 49 CFR 383.135

$12

Iowa commercial learner's permit fee

Iowa DOT CLP and Fees pages

14 days

Minimum CLP holding period before skills and drive test

Iowa DOT CDL Testing

Section 6

Iowa CDL Manual section for Combination Vehicles

Iowa DOT CDL Manual

Iowa DOT lists Combination Vehicle for Class A as a 20-question test with 4 allowed misses, matching FMCSA's 80% CDL knowledge-test passing rule. Applicants should study Iowa CDL Manual Section 6 and know coupling, uncoupling, trailer air-brake controls, off-tracking, rollover, backing, and combination inspection before testing.

Sample Iowa CDL Combination Vehicles Test Practice Questions

Try these sample questions to test your Iowa CDL Combination Vehicles Test exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 200+ question experience with AI tutoring.

1Iowa DOT lists the Class A Combination Vehicle knowledge test as how many questions?
A.50
B.20
C.10
D.25
Explanation: Iowa DOT lists Combination Vehicle for Class A as 20 questions with 4 allowed misses.
2How many questions may be missed on Iowa DOT's 20-question Combination Vehicle test?
A.5
B.10
C.4
D.2
Explanation: Iowa DOT publishes the Combination Vehicle format as 20/04, meaning 20 questions and 4 allowed misses.
3What is the FMCSA minimum passing score for CDL knowledge tests?
A.60%
B.70%
C.90%
D.80%
Explanation: FMCSA and 49 CFR 383.135 require at least 80% correct on CDL knowledge tests.
4The Combination Vehicle test is mainly for applicants seeking which CDL class?
A.Class A
B.Class B only
C.Class C only
D.Motorcycle endorsement
Explanation: Iowa DOT lists Combination Vehicle for Class A because Class A covers qualifying commercial combinations.
5For a federal Class A combination, the towed unit is generally over what threshold?
A.26,001 pounds
B.10,000 pounds
C.5,000 pounds
D.8,000 pounds
Explanation: FMCSA Class A standards use a towed-unit threshold over 10,000 pounds with a qualifying combination weight.
6Which vehicle is a combination vehicle?
A.A passenger car
B.A single dump truck with no trailer
C.A tractor pulling a semitrailer
D.A straight box truck with no trailer
Explanation: A combination vehicle has a power unit coupled to one or more trailers.
7Why do combination vehicles require more skill than single CMVs?
A.They are always shorter
B.They do not use mirrors
C.They have no cargo
D.They are usually longer, heavier, and harder to maneuver
Explanation: The Iowa CDL manual explains that combinations are usually heavier, longer, and require more driving skill.
8What cargo condition raises rollover risk?
A.Cargo loaded high or off-center
B.Cargo kept low and centered
C.Speed reduced before ramps
D.Smooth steering
Explanation: High or off-center cargo raises the center of gravity or makes the trailer lean, increasing rollover risk.
9What driver action causes many combination-vehicle rollovers?
A.Keeping space ahead
B.Turning too fast
C.Checking mirrors
D.Backing slowly
Explanation: The Iowa manual warns that rollovers happen when drivers turn too fast, especially on ramps and curves.
10What does the crack-the-whip effect involve?
A.Normal air-tank draining
B.Landing gear cranking
C.Quick steering amplified toward the rear trailer
D.Fifth wheel lubrication
Explanation: Rearward amplification can make the trailer move more sharply than the tractor and possibly overturn.

About the Iowa CDL Combination Vehicles Test Exam

The Iowa CDL Combination Vehicles test is the Class A knowledge exam for applicants who plan to operate tractor-trailers or other qualifying commercial combinations. Iowa DOT lists the test as 20 questions with 4 allowed misses and directs applicants to the Iowa Commercial Driver License Manual. The tested content follows FMCSA CDL standards and Iowa manual Section 6, including rollover prevention, smooth steering, braking early, trailer skids and jackknife recovery, off-tracking and wide turns, backing with a trailer, trailer hand valve limits, tractor protection valve, trailer air supply, service and emergency air lines, glad hands, trailer air tanks, shut-off valves, ABS, coupling, uncoupling, landing gear, fifth wheel, kingpin, air and electrical lines, and combination-vehicle inspection.

Assessment

20 multiple-choice Combination Vehicle questions for Iowa Class A CDL applicants, with separate General Knowledge, Air Brake, endorsement, and Iowa operator tests required when applicable.

Time Limit

No separate official time limit published by Iowa DOT for the Combination Vehicle knowledge test

Passing Score

80% (16 correct out of 20; Iowa DOT allows 4 misses)

Exam Fee

$12 Iowa CLP; Class A, B, and C commercial licenses are $8 per year; endorsement and restriction-removal fees are separate (Iowa Department of Transportation under FMCSA CDL standards)

Iowa CDL Combination Vehicles Test Exam Content Outline

18%

Combination Vehicle Handling

Rollover risk, rearward amplification, smooth steering, braking early, speed control, following distance, bobtail handling, and night or curve speed choices.

16%

Turns, Off-Tracking, and Backing

Right and left turn path control, curb and pedestrian clearance, off-tracking, driver-side backing, pull-ups, mirror use, and get-out-and-look checks.

22%

Coupling Tractor-Semitrailers

Fifth wheel inspection, trailer height, kingpin and jaws, air-line connection, tug test, visual inspection, electrical cord, landing gear, and clearance checks.

14%

Uncoupling Tractor-Semitrailers

Parking surface, trailer brake and chock decisions, lowering landing gear, disconnecting lines, releasing the fifth wheel, partial pullout, and final support checks.

18%

Trailer Air Brakes and ABS in Combinations

Trailer hand valve limits, tractor protection valve, trailer air supply, service and emergency lines, glad hands, shut-off valves, air tanks, ABS lamps, and brake checks.

12%

Combination Inspection and Iowa CDL Basics

Combination-only inspection items, Iowa Class A Combination Vehicle test format, 80% FMCSA passing standard, CLP steps, fees, ELDT, and representative vehicle restrictions.

How to Pass the Iowa CDL Combination Vehicles Test Exam

What You Need to Know

  • Passing score: 80% (16 correct out of 20; Iowa DOT allows 4 misses)
  • Assessment: 20 multiple-choice Combination Vehicle questions for Iowa Class A CDL applicants, with separate General Knowledge, Air Brake, endorsement, and Iowa operator tests required when applicable.
  • Time limit: No separate official time limit published by Iowa DOT for the Combination Vehicle knowledge test
  • Exam fee: $12 Iowa CLP; Class A, B, and C commercial licenses are $8 per year; endorsement and restriction-removal fees are separate

Keys to Passing

  • Complete 500+ practice questions
  • Score 80%+ consistently before scheduling
  • Focus on highest-weighted sections
  • Use our AI tutor for tough concepts

Iowa CDL Combination Vehicles Test Study Tips from Top Performers

1Study Iowa CDL Manual Section 6 before drilling questions; it is the direct source for combination-vehicle knowledge.
2Memorize coupling and uncoupling steps in order, especially trailer height, air-line connection, tug test, visual fifth wheel inspection, landing gear, and wheel chocks.
3Practice explaining why the trailer hand valve is not used for normal stopping, parking, or straightening a skid.
4Use mirrors constantly in skid, turn, lane-change, and backing scenarios because trailer position is tested repeatedly.
5Separate Combination Vehicle content from Air Brakes and Doubles/Triples; learn only the air and multi-trailer details needed for Class A combination context.
6Before testing, verify current Iowa DOT fees, CLP rules, testing locations, and required documents.

Frequently Asked Questions

Who administers the Iowa CDL Combination Vehicles test?

The Iowa Department of Transportation administers Iowa CDL knowledge testing through DOT, County Treasurer, and other listed CDL testing locations under FMCSA CDL standards.

How many questions are on the Iowa CDL Combination Vehicles test?

Iowa DOT lists Combination Vehicle for Class A as 20 questions with 4 allowed misses.

What score do I need to pass?

FMCSA requires at least 80% correct on CDL knowledge tests. Iowa's 20-question/4-miss Combination Vehicle format means you need at least 16 correct answers.

What should I study for Iowa CDL Combination Vehicles?

Use Iowa CDL Manual Section 6 for combination handling, rollover, trailer skids, wide turns, backing, trailer air lines and controls, ABS, coupling, uncoupling, and inspection.

Is the Iowa Combination Vehicle test the same as Air Brakes or Doubles/Triples?

No. Iowa DOT lists Combination Vehicle, Air Brake, and Doubles/Triples as separate CDL knowledge tests. Air-brake and doubles/triples details are included here only where they affect combination-vehicle operation.

How much does the Iowa CLP cost?

Iowa DOT lists the commercial learner's permit at $12. Class A, B, and C commercial licenses are listed at $8 per year, and endorsement or restriction-removal fees may apply separately.