Idaho General Knowledge CDL Practice Test
Below are 25 exam-style questions for the Idaho General Knowledge CDL knowledge test, modeled on the FMCSA-aligned content used by the Idaho Transportation Department Division of Motor Vehicles. Try to answer each question on your own before reading the answer key directly under it. The questions and answer choices are shuffled deterministically per state and endorsement, so the order will stay the same on repeat visits — that lets you genuinely measure your improvement.
- A Powertrain wear and possible loss of control on slippery surfaces
- B Annoying passengers
- C Engine damage
- D Wasting fuel only
- A Pumping the brakes hard and fast
- B Applying the brakes as hard as possible without locking the wheels
- C Coasting in neutral
- D Locking the wheels
- A Bridge surfaces freeze first because of air circulation underneath
- B Bridges are inspected only in winter
- C The pavement under the bridge is reinforced
- D The bridge is closed in winter
- A It applies the parking brake
- B It increases brake pressure automatically
- C It prevents wheel lockup so the driver can keep steering
- D It always stops the vehicle in a shorter distance
- A It would make you exceed federal hours-of-service rules
- B It would push your weight over legal limits
- C All of the above
- D The cargo is not properly secured or placarded
- A Speed up to get away
- B Move to the left lane only
- C Brake suddenly to teach a lesson
- D Increase your following distance from the vehicle in front to give both of you more room
- A 6 seconds
- B 4 seconds
- C 10 seconds
- D 1 second
- A Need to take it again later
- B Took the test and failed
- C Did not take the test, with no consequence
- D Took the test and passed
- A It wastes brake pads
- B It cools the brakes too much
- C Brake fade can leave you with reduced or no braking power
- D It triggers the ABS warning light
- A A passenger door is open
- B A trailer brake light is out
- C A vehicle is in safe operating condition
- D Required emergency equipment is missing
- A All of the above
- B Make smooth steering and braking inputs
- C Slow down
- D Increase following distance
- A To save fuel
- B On wet roads only
- C On vehicles with ABS
- D On vehicles without ABS, to keep them straight in an emergency
- A Accelerate
- B Brake hard immediately
- C Steer sharply in the opposite direction
- D Release the brake, let the wheels turn freely, and let the vehicle slow down
- A Whenever you feel like it
- B When you are stopped or moving slowly enough to be a hazard
- C Only on the highway
- D Only at night
- A To save fuel and improve mileage
- B So the brake lights don't mislead following drivers and so the brakes don't overheat
- C To rest the right leg
- D To save brake pads and reduce drag
- A The range of your low-beam headlights
- B Half the range of your low-beam headlights
- C The full range of high-beam headlights when in use
- D Whatever speed feels safe
- A Back without using mirrors so you can watch out the window
- B Back fast to get it over with
- C Back to the right whenever possible
- D Use a helper and walk around the vehicle first
- A Engine braking helps keep speed under control
- B Brakes alone are not designed to hold a heavy vehicle on a long downgrade
- C Heavy vehicles can slow down sharply on grades
- D All of the above
- A Downshift in the curve
- B Brake while in the curve
- C Stay at the same speed
- D Slow down before entering and accelerate gently through it
- A Steer sharply toward the shoulder
- B Brake immediately and pull off the road
- C Hold the steering wheel firmly, ease off the accelerator, and let the vehicle slow down
- D Shift to neutral and coast
- A A federal speed restriction
- B The area in front of the steer axle
- C The fuel tank area
- D The area immediately next to it where other drivers are hidden in your blind spots
- A A warning
- B No federal consequence
- C A fine only
- D CDL disqualification for at least one year for a first offense
- A A fuel-saving switch
- B A type of cargo strap
- C A low-air pressure warning device that drops a flag in front of the driver
- D A trailer hitch component
- A High beams improve visibility in heavy rain
- B Tire chains are required by federal law
- C Roads are most slippery just after rain begins, when water mixes with road oil
- D It is safe to drive at the posted speed limit
- A Setting the parking brake, releasing the service brakes, and gently trying to move the vehicle in low gear
- B Pumping the brakes
- C Driving over a speed bump
- D Releasing the parking brake on a flat surface and tugging gently against it
Study tips for the Idaho General Knowledge exam
The General Knowledge portion of the Idaho CDL exam is graded out of the bank of questions the Idaho Transportation Department Division of Motor Vehicles draws from each year. While the exact bank is not published, every question is sourced from the General Knowledge chapter of the Idaho CDL handbook, which itself is derived from the FMCSA Model Commercial Driver's License Manual. That means studying our practice tests, reading the corresponding handbook chapter, and re-reading the parts you got wrong is genuinely the most efficient route to a first-time pass.
Most successful applicants follow a simple cycle: take the practice test cold, write down every question you missed, open the matching chapter of the official Idaho handbook, re-read the section that contains the right answer, then re-take the practice test 24 to 48 hours later. The 24-hour delay matters — sleep is when your brain commits new information to long-term memory, and CDL knowledge questions reward that kind of consolidated learning rather than cramming.
Pay particular attention to questions that include qualifier words like always, never, only, primary, or most. CDL test writers love to flip the right answer with a single qualifier. When two answer choices look almost identical, pay attention to the verb (is it must, should, or may?) and to any numbers (14 days, 100 air miles, 8 hours, 70/8 split). On endorsement tests in particular, watch for trick framing where a true statement about a different endorsement is offered as the "correct" answer to a question that is actually about General Knowledge.
Test-day logistics matter too. Bring photo ID, your Social Security card or birth certificate, your medical examiner's certificate (DOT card), and proof of state residency if you haven't already submitted those documents. The Idaho Transportation Department Division of Motor Vehicles will not let you sit for the knowledge exam without your documentation, and most offices charge an additional fee for re-attempts. Arrive early — the wait at most CDL testing offices runs 30 to 60 minutes — and silence your phone before the exam begins.
Finally, keep your General Knowledge fundamentals sharp even when you're focused on the General Knowledge exam. Many states administer multiple knowledge tests in a single sitting, and questions on weight definitions (GVWR, GCWR, GAWR), stopping distance, and the pre-trip inspection routine show up across endorsements. If you're unsure on the basics, sit a fresh Idaho General Knowledge practice test before scheduling the real exam.
Next steps
Missed more than four questions? Re-read the General Knowledge study guide and the matching chapter in the official Idaho CDL handbook. Then come back and re-take the test. Once you can score 22 of 25 or higher on three runs in a row, you're in good shape to schedule the real exam at your local Idaho Transportation Department Division of Motor Vehicles office.
Already comfortable with this endorsement? Drill another: ID Air Brakes · ID Combination Vehicles · ID Hazardous Materials · ID Passenger · ID School Bus · ID Tank Vehicle · ID Doubles / Triples
New to the CDL process in Idaho? Read How to apply for a CDL in Idaho for the document checklist and step-by-step timeline.