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300+ Free ID CDL General Knowledge Practice Questions

Pass your Idaho CDL General Knowledge Test exam on the first try — instant access, no signup required.

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Which headlight setting should you use when driving in heavy fog?

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2026 Statistics

Key Facts: ID CDL General Knowledge Exam

80%

Minimum CDL knowledge-test passing score

FMCSA

At least 30

Minimum items on each basic knowledge test

FMCSA

18

Minimum age to apply for an Idaho CDL

ITD

1 year

Licensed driving experience needed to obtain an Idaho CDL

ITD

$5

Idaho written CDL knowledge test fee

ITD

$29

Idaho CLP fee

ITD

14 days

Minimum CLP holding period before skills testing

ITD/FMCSA

Idaho states that the General Knowledge test is required for all new CDL applicants. ITD lists written CDL tests at $5.00 each, an Idaho CLP at $29 and valid for one year, a three-day wait to retest after a failed written test, and a 14-day minimum CLP holding period before skills testing. FMCSA requires basic CDL knowledge tests to cover the 20 areas in 49 CFR 383.111(a), contain at least 30 items, and use an 80% passing standard.

Sample ID CDL General Knowledge Practice Questions

Try these sample questions to test your ID CDL General Knowledge exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 300+ question experience with AI tutoring.

1When beginning a pre-trip inspection, what should an Idaho CDL applicant do first?
A.Start the engine and drive forward to test acceleration
B.Approach the vehicle and look for overall condition, damage, leaks, and leaning
C.Check only the cargo doors before entering the cab
D.Release the parking brake and listen for air leaks
Explanation: The CDL inspection method starts with an overall approach to the vehicle so obvious leaks, damage, leaning, or hazards are found before detailed checks.
2Which group of items belongs in an engine-compartment inspection?
A.Oil, coolant, power steering fluid, belts, hoses, and leaks
B.Only the windshield washer fluid and mirrors
C.Only the fifth wheel and trailer doors
D.Only tire tread depth and wheel seals
Explanation: Engine-compartment checks include fluids, belts, hoses, and leaks because failures there can create breakdowns, fire risks, or loss of steering assistance.
3What minimum tread depth is required on front steering-axle tires?
A.2/32 inch
B.4/32 inch
C.1/32 inch
D.No minimum if the tire is properly inflated
Explanation: Steering-axle tires must have at least 4/32 inch tread depth because they are critical to directional control.
4What minimum tread depth is required on most non-steering axle tires?
A.4/32 inch
B.3/32 inch
C.2/32 inch
D.6/32 inch
Explanation: Drive and trailer tires generally require at least 2/32 inch tread depth in major grooves.
5Which emergency equipment should a CMV carry for roadside emergencies?
A.A CB radio, spare tire, and first-aid kit only
B.A fire extinguisher, spare electrical fuses when needed, and warning devices such as three reflective triangles
C.Only road flares because triangles are optional
D.A tow chain and extra fuel can
Explanation: General CDL knowledge includes required emergency equipment such as a charged fire extinguisher and warning devices to protect the stopped vehicle scene.
6During a vehicle inspection, which lights should be checked?
A.Only headlights
B.Headlights, turn signals, brake lights, four-way flashers, clearance lights, and reflectors
C.Only lights required at night
D.Only trailer lights, because tractor lights are checked during service
Explanation: A driver must confirm that lighting and reflective equipment works because it communicates vehicle size, stopping, turning, and hazards to other road users.
7What does excessive brake pushrod travel usually indicate on an air-brake vehicle?
A.The brakes may be out of adjustment
B.The parking brake is stronger than normal
C.The engine brake is working properly
D.The steering axle is overloaded
Explanation: Excessive pushrod travel means the brake may not apply fully and can reduce stopping power.
8For an air-brake vehicle, why is the air pressure buildup test important?
A.It confirms the compressor can restore pressure fast enough for safe braking
B.It proves the fuel pump is working
C.It measures tire inflation pressure
D.It replaces the need to inspect brake drums
Explanation: Air brakes depend on stored pressure, so slow pressure buildup can indicate compressor problems or leaks that threaten braking ability.
9What should a driver do with a defect that affects safe operation?
A.Drive until the next scheduled maintenance interval
B.Have it corrected before operating the vehicle
C.Ignore it if the trip is short
D.Report it only after cargo is delivered
Explanation: Defects affecting safe operation must be corrected before driving because the driver is responsible for operating a safe CMV.
10After starting a trip, when should cargo securement first be rechecked?
A.Within the first 50 miles
B.Only at the destination
C.After 500 miles
D.Only if the load is uncovered
Explanation: Cargo securement must be checked early in the trip because tie-downs can loosen and cargo can shift shortly after movement begins.

About the ID CDL General Knowledge Exam

The Idaho CDL General Knowledge test is the base written knowledge exam for new Idaho CDL applicants. It is administered through Idaho DMV offices under federal CDL standards and should be studied with the Idaho Commercial Driver's License Manual. The general knowledge scope includes safe operation regulations, vehicle control systems, inspections, basic control, shifting, backing, visual search, communication, speed and space management, adverse conditions, hazards, emergencies, skid recovery, cargo control, fatigue, alcohol/drug effects, and Idaho CDL licensing basics.

Assessment

FMCSA requires each basic CDL knowledge test to contain at least 30 items; Idaho administers the state General Knowledge test for CDL applicants.

Time Limit

Set by Idaho testing administration; no separate public time limit found in official sources

Passing Score

80% minimum on CDL knowledge tests

Exam Fee

$5 per written knowledge test; $29 CLP; $10 county skills-test fee plus examiner fee up to $190 (Idaho Transportation Department Division of Motor Vehicles (ITD DMV))

ID CDL General Knowledge Exam Content Outline

ITD CDL page and ten-step guide

Idaho CDL Basics

Idaho CDL classes, who needs a CDL, age 18 minimum, one year licensed driving experience, medical certification, ELDT, CLP rules, fees, and retesting

49 CFR 383.111(a)(17)

Vehicle Inspection

Pre-trip, enroute, and post-trip inspections; brakes, tires, lights, steering, suspension, coupling, leaks, mirrors, emergency equipment, and defect reporting

49 CFR 383.111(a)(4)-(6)

Basic Control, Shifting, and Backing

Starting, stopping, backing, turning, off-tracking, shifting procedures, speed control, and large-vehicle maneuvering

49 CFR 383.111(a)(7)-(10)

Seeing, Communication, Speed, and Space

Visual search, mirror use, signaling, blind spots, stopping distance, following distance, traffic gaps, lane changes, and work zones

49 CFR 383.111(a)(11)-(15), (19)-(20)

Adverse Conditions and Emergencies

Night driving, fog, rain, snow, mountain grades, railroad crossings, hazard perception, evasive steering, brake failure, blowouts, fires, skids, and crash procedures

49 CFR 383.111(a)(1), (16), (18)

Cargo, Wellness, Alcohol, Drugs, and Regulations

Cargo securement, weight distribution, driver responsibilities, fatigue, health, alcohol/drug effects, Idaho licensing logistics, and FMCSA test standards

How to Pass the ID CDL General Knowledge Exam

What You Need to Know

  • Passing score: 80% minimum on CDL knowledge tests
  • Assessment: FMCSA requires each basic CDL knowledge test to contain at least 30 items; Idaho administers the state General Knowledge test for CDL applicants.
  • Time limit: Set by Idaho testing administration; no separate public time limit found in official sources
  • Exam fee: $5 per written knowledge test; $29 CLP; $10 county skills-test fee plus examiner fee up to $190

Keys to Passing

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

ID CDL General Knowledge Study Tips from Top Performers

1Start with Chapter 1 of the latest Idaho CDL handbook for Idaho-specific CDL process, medical certification, ELDT, and test-selection rules.
2Use 49 CFR 383.111(a) as a checklist for General Knowledge: inspection, controls, shifting, backing, seeing, communication, speed, space, weather, hazards, emergencies, skids, cargo, mountain driving, fatigue, alcohol, and drugs.
3Memorize Idaho logistics that are easy test-day misses: $5 written tests, three-day written-test retest wait, $29 CLP, one-year CLP validity, and 14-day CLP holding period before skills testing.
4Practice inspection questions by identifying the defect, why it matters, and whether the vehicle should be operated before repair.
5For speed and space questions, choose the answer that gives the CMV more time, more room, and smoother control.
6Keep endorsement-only details secondary unless they overlap with General Knowledge, such as basic hazmat awareness or air-brake inspection concepts for the vehicle you drive.

Frequently Asked Questions

Who must take the Idaho CDL General Knowledge test?

ITD states that the General Knowledge test is required of all new Idaho CDL applicants. Depending on the vehicle, applicants may also need other knowledge tests such as Air Brakes or Combination Vehicles.

What score do I need to pass the Idaho CDL General Knowledge test?

FMCSA requires applicants to answer at least 80 percent of CDL knowledge-test questions correctly. Idaho CDL testing must meet that federal standard.

How many questions are on the Idaho CDL General Knowledge test?

FMCSA requires each basic CDL knowledge test to contain at least 30 items. The official Idaho sources reviewed do not publish a separate Idaho-specific public item count for the General Knowledge test.

How much does Idaho CDL written testing cost?

ITD states that written CDL tests are $5.00 each. Idaho also lists a $29 CLP fee, a $10 county skills-test fee, and a separate CDL examiner fee that cannot exceed $190.

Can I retake a failed Idaho CDL written test?

Yes. ITD states that if you fail a written test, you can retest in three days and pay another five dollars.

Does Idaho require ELDT before the CDL skills test?

For covered applicants, yes. Idaho states that as of February 7, 2022, CDL applicants subject to Entry-Level Driver Training must complete training from a provider listed on FMCSA's Training Provider Registry before required skills tests.