Iowa CDL Practice Test 2026: Free Study Guide & Tests
8–12 minutes
Iowa CDL Practice Test 2026: Free Study Guide & Tests
You’re planning to get your Commercial Driver’s License in Iowa — and you picked a state where trucking is the backbone of the economy. Iowa’s agricultural industry relies on CDL drivers to move corn, soybeans, livestock, and processed foods across the state and beyond. With major interstate corridors like I-80 and I-35 crossing through the Hawkeye State, Iowa drivers are essential to keeping America’s food supply chain moving.
But before you can start hauling grain on the rolling prairies or navigating the bridges over the Mississippi and Missouri Rivers, you need to pass the Iowa CDL exam. The Iowa Department of Transportation (Iowa DOT) administers the CDL program under federal FMCSA guidelines, and the process is rigorous by design — because the stakes on the road are real.
This guide gives you everything you need to prepare for the Iowa CDL test: exact test format, Iowa-specific requirements, what’s different from other states, and free practice tests covering every knowledge exam you’ll face.
Iowa follows the federal CDL standards established by the FMCSA under 49 CFR Part 383, with some state-specific requirements administered by the Iowa Department of Transportation (Iowa DOT). Here’s exactly what Iowa requires:
Age Requirements in Iowa
License Type
Minimum Age
Restrictions
Intrastate (Iowa only)
18 years
Cannot drive across state lines
Interstate (all states)
21 years
No state-line restrictions
HazMat Endorsement
21 years
Federal requirement — no exceptions
Iowa CDL Fees
Fee Type
Amount
Details
CLP Application
$12.00
Valid for 12 months
CDL License Fee
$8.00
Standard CDL issuance fee
Knowledge Test Fee
$6.00 per test
Each knowledge exam
Skills Test Fee
$50.00
Three-part skills test
Endorsement Fees
$2.00–$10.00
Per endorsement
Iowa ELDT Requirements
Since February 7, 2022, all new CDL applicants in Iowa must complete Entry-Level Driver Training (ELDT) through an FMCSA-approved training provider. This is a federal requirement — no state can waive it. Iowa DOT verifies ELDT completion electronically through the FMCSA Training Provider Registry (TPR).
ELDT is required for:
Original Class A or Class B CDL
Upgrading from Class B to Class A
First-time School Bus (S), Passenger (P), or HazMat (H) endorsements
You must hold your Commercial Learner’s Permit (CLP) for at least 14 days before taking the skills test. Your CLP is valid for 12 months in Iowa — longer than many other states.
Iowa CDL Test Format: What to Expect
The Iowa CDL exam has two parts: knowledge tests (written) and a skills test (driving). The knowledge tests are computer-based, multiple-choice, and administered at Iowa DOT driver’s license stations throughout the state.
Knowledge Tests Overview
Test
Questions
Pass Score
Required For
General Knowledge
50
80% (40 correct)
All CDL classes
Air Brakes
25
80% (20 correct)
Class A & B (if vehicle has air brakes)
Combination Vehicles
20
80% (16 correct)
Class A
HazMat (H)
30
80% (24 correct)
HazMat endorsement
Tanker (N)
20
80% (16 correct)
Tanker endorsement
Passenger (P)
20
80% (16 correct)
Passenger endorsement
School Bus (S)
20
80% (16 correct)
School bus endorsement
Doubles/Triples (T)
20
80% (16 correct)
Double/triple trailers
All Iowa CDL knowledge tests follow FMCSA content standards from the Iowa CDL Handbook. The passing score is 80% on every test — no exceptions.
Iowa Skills Test: Three Parts
The Iowa CDL skills test is administered directly by the Iowa DOT at driver’s license stations — not through third-party testers. You must provide your own vehicle for the test, and it must be the same class of vehicle you’re applying for and meet federal safety standards.
Section
What It Tests
Details
1. Pre-Trip Inspection
Vehicle safety knowledge
Verbally identify and explain critical components: engine, brakes, tires, lights, coupling systems
2. Basic Vehicle Control
Backing and maneuvering
Straight-line backing, offset backing, parallel parking, alley dock
3. On-Road Driving
Real-world driving
Lane changes, turns, braking, gear usage, speed management, traffic law compliance
Iowa skills test retake policy: If you fail any section, you only retake the failed section. The waiting period is 1 business day for knowledge tests and 3 days for skills tests between retakes. Iowa allows unlimited attempts within your CLP validity period.
What Makes Iowa CDL Different from Other States?
The core CDL exam is federally standardized — the General Knowledge, Air Brakes, and endorsement tests cover the same material in every state. But Iowa has specific characteristics that make driving here unique:
Iowa-Specific Driving Conditions
Flat to gently rolling terrain: Iowa’s landscape is mostly prairie — long stretches of highway that can lead to driver fatigue on I-80 and I-35
Severe winter weather: Heavy snowfall, ice storms, and blizzard conditions are common from November through March, requiring advanced winter driving skills
Agricultural dominance: Iowa is a top producer of corn, soybeans, hogs, and cattle — expect heavy farm equipment traffic during planting (April-May) and harvest (September-October)
River crossings: The Mississippi, Missouri, and Des Moines Rivers create bridges and flood-prone corridors that require extra caution
Wind exposure: Open plains mean high crosswinds on I-80, I-35, and I-29 — especially dangerous for high-profile vehicles and tankers
Tornado alley: Spring and summer bring severe thunderstorms and tornadoes — drivers need weather awareness and emergency shelter knowledge
Spring flooding: River valleys experience flooding that can close bridges and require alternate routing through rural areas
Extreme temperature swings: Very cold winters (below 0°F) to hot humid summers (above 90°F) — both extremes affect tire pressure, equipment, and cargo
Renewable energy transport: Wind turbine components are frequently moved through Iowa on oversized loads — expect escort vehicles and special routing
Grain transportation: Major grain corridors require knowledge of elevator operations, weight limits, and agricultural cargo securement
While the CDL knowledge test itself won’t ask you Iowa-specific questions beyond what’s in the standard handbook, understanding these conditions will make you a safer driver and help you contextualize the safety rules you’re learning. Iowa’s flat terrain can be deceptive — the challenges here come from weather, wind, and sharing roads with farm equipment.
Free Iowa CDL Practice Tests
Each practice test below covers one of the knowledge exams required for your Iowa CDL. Questions are based on the FMCSA CDL Manual and the Iowa CDL Handbook. Select the test you need to prepare for:
Core Tests (Required for All CDL Applicants)
General Knowledge Practice Test — 50 questions covering vehicle inspection, safe driving, cargo management, and CDL regulations
Meet the prerequisites: Be at least 18 (intrastate) or 21 (interstate), hold a valid Iowa driver’s license, and pass a DOT medical exam
Complete ELDT training: Enroll in an FMCSA-approved Entry-Level Driver Training program and complete the theory portion
Get your CLP: Visit an Iowa DOT driver’s license station, pay the $12 fee, and pass the required knowledge tests to get your Commercial Learner’s Permit (valid 12 months)
Hold your CLP for 14 days: Practice driving with a qualified CDL holder in the vehicle with you
Schedule your skills test: Contact your local Iowa DOT office to book your skills test appointment
Pass the three-part skills test: Pre-trip inspection, basic vehicle control, and on-road driving at an Iowa DOT location
Get your Iowa CDL: Return to Iowa DOT with your test results, pay the $8 CDL fee, and get your new license
Iowa CDL Frequently Asked Questions
How many questions are on the Iowa CDL General Knowledge test?
The Iowa CDL General Knowledge test has 50 multiple-choice questions. You need to answer at least 40 correctly (80%) to pass. The test covers vehicle inspection, safe driving practices, cargo management, CDL regulations, and more.
How much does an Iowa CDL cost?
The total cost includes a $12 CLP application fee, a $50 skills test fee, and an $8 CDL license fee. Each knowledge test costs $6, and endorsements range from $2–$10. Additional costs include your DOT medical exam (typically $75–$150) and ELDT training ($3,000–$8,000 if attending a school). Iowa’s CLP is valid for 12 months, longer than many other states.
What happens if I fail an Iowa CDL knowledge test?
If you fail a knowledge test, you can retake it the next business day. Iowa allows unlimited attempts within your CLP validity period (12 months). Each retake requires paying the $6 test fee again. We recommend using our practice tests until you consistently score above 80% before attempting the real exam.
Can I get an Iowa CDL at 18?
Yes. Iowa allows you to get a CDL at 18 for intrastate driving only (within Iowa). You cannot cross state lines until you turn 21. The HazMat endorsement requires you to be at least 21, regardless of your license type.
Where do I take the Iowa CDL skills test?
Iowa CDL skills tests are administered directly by the Iowa DOT at driver’s license stations throughout the state — not through third-party testers. Testing locations include Des Moines, Cedar Rapids, Davenport, Council Bluffs, Sioux City, Waterloo, and Ames. You must provide your own vehicle for the test — it must match the class of license you’re applying for.
Is the Iowa CDL test the same as other states?
The knowledge tests are based on the same FMCSA standards and cover the same material as in every other state. The Iowa DOT follows the federal CDL manual closely. Questions about vehicle inspection, safe driving, cargo securement, and endorsements are standardized nationally. Your Iowa CDL is valid in all 50 states.
Iowa’s agricultural economy depends on qualified CDL drivers — from grain haulers to livestock transporters. Whether you’re looking to work in ethanol production, food processing, or regional freight, your CDL is your ticket to a stable career in the heartland.
Our free practice tests are designed to match the real Iowa CDL exam format — same question count, same passing score, same content areas. Use them until you’re consistently scoring above 80%, and you’ll walk into the Iowa DOT testing center with confidence.
Free Iowa CDL Practice Test — Try It Now
Ready to test your knowledge? Take this free CDL General Knowledge practice test right here — no registration, no sign-up, no payment. These questions mirror the real CDL exam format covering vehicle inspection, safe driving, cargo management, and federal regulations. Score 80% or higher and you’re on track to pass your Iowa CDL exam.
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Answered
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Question 1 of 50
1. Question
1. During the cab check portion of a pre-trip inspection, the driver verifies the fire extinguisher. What is the requirement for the fire extinguisher to be considered properly maintained and ready for use?
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Question 2 of 50
2. Question
2. What is “off-tracking” in the context of commercial motor vehicle operation?
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Incorrect
Question 3 of 50
3. Question
3. A driver is preparing to start a loaded tractor-semitrailer on a steep downhill grade. The vehicle has a 10-speed manual transmission. Place the following steps in the correct sequence for a safe start:
1. Release parking brake
2. Shift transmission to first gear
3. Apply service brake pedal
4. Depress clutch pedal fully to engage clutch brake
5. Gradually release clutch while applying accelerator
6. Verify vehicle is secure and mirrors adjusted
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Incorrect
Question 4 of 50
4. Question
4. What is the motor carrier’s responsibility when receiving a Driver Vehicle Inspection Report (DVIR) that lists vehicle defects?
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Incorrect
Question 5 of 50
5. Question
5. A passenger vehicle is following your 65-foot combination vehicle too closely on a two-lane highway. What is the BEST action to handle this tailgater?
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Incorrect
Question 6 of 50
6. Question
6. A CDL driver performs a pre-trip inspection on a Class A tractor-semitrailer and finds the following conditions: one wheel rim on the drive axle has a visible crack approximately 1 inch long, two U-bolts on the trailer axle appear loose (can be moved by hand), and the fire extinguisher gauge shows it is in the “discharged” zone. Which analysis correctly identifies the vehicle’s operational status?
Correct
Incorrect
Question 7 of 50
7. Question
7. A driver must back a loaded tractor-semitrailer into a dock located on a slight downgrade (2% slope) that the driver is approaching from above. The dock area has limited space. Which backing approach accounts for the downgrade most safely?
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Question 8 of 50
8. Question
8. A driver’s ELD malfunctions during a trip and displays an error message. Under 49 CFR 395.34, what must the driver do?
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Question 9 of 50
9. Question
9. At 55 mph on dry pavement, what is the approximate total stopping distance for a loaded commercial motor vehicle?
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Question 10 of 50
10. Question
10. A flatbed driver has secured a cargo of dressed lumber (packaged boards) using the required tiedowns. The driver has traveled 35 miles from the loading location. What action must the driver take regarding cargo inspection?
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Question 11 of 50
11. Question
11. A driver is approaching a construction zone on an interstate highway where traffic has slowed significantly. The driver needs to warn following traffic of the sudden slowdown ahead. Which communication device should be activated?
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Question 12 of 50
12. Question
12. A driver is inspecting the air brake system air storage tanks during a pre-trip inspection. The driver opens the drain valve on a tank and observes that only a small amount of moisture drains out, followed by clear air. The driver then checks another tank and finds that the drain valve is stuck and cannot be opened. What should the driver determine and report about these tank drain valve conditions?
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Question 13 of 50
13. Question
13. What is the maximum acceptable tilt angle for a fifth wheel during pre-trip inspection?
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Question 14 of 50
14. Question
14. What is the primary mechanical difference between wedge brakes and S-cam brakes in an air brake foundation brake system?
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Question 15 of 50
15. Question
15. A driver is navigating a 90-degree right turn from a two-lane road onto a narrow street. The combination vehicle is 70 feet long overall. The driver notices a fire hydrant positioned 4 feet from the curb on the corner of the destination street. Based on off-tracking principles, what should the driver do?
Correct
Incorrect
Question 16 of 50
16. Question
16. A driver performing a trailer pre-trip inspection on a Class A combination vehicle notices that the landing gear handle is missing, but the crank mechanism is accessible using a universal wrench. The landing gear legs appear fully raised and secured. What should the driver do regarding this defect?
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Incorrect
Question 17 of 50
17. Question
17. A 60-foot combination vehicle is traveling at 55 mph on a dry highway. At this speed, perception distance is approximately 142 feet, reaction distance is approximately 61 feet, and braking distance is approximately 150 feet for a loaded CMV. What is the total stopping distance?
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Question 18 of 50
18. Question
18. A driver loaded a 3-foot-long crate weighing 4,000 pounds and used one strap with a WLL of 1,500 pounds to secure it. The cargo shifted during transport, causing the strap to break. Which TWO regulatory violations contributed to this cargo securement failure?
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Question 19 of 50
19. Question
19. A CDL driver has accumulated the following convictions within the past three years: (1) speeding 20 MPH over the limit in a CMV, (2) improper lane change in a personal vehicle, (3) following too closely in a CMV, (4) failing to stop at a railroad crossing in a CMV. Which analysis correctly determines whether this driver faces disqualification?
Correct
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Question 20 of 50
20. Question
20. You are driving a loaded tractor-semitrailer on a mountain downgrade when you notice your brakes are beginning to fade—the brake pedal feels soft, and stopping power is reduced despite normal pedal pressure. You have been using the brakes frequently to control speed on the grade. What is the correct immediate response to brake fade on a downgrade?
Correct
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Question 21 of 50
21. Question
21. A driver is calculating the minimum following distance for a 70-foot combination vehicle traveling at 60 mph on a dry interstate highway. Traffic ahead is moving at approximately 55 mph, creating a closing speed differential. The driver maintains 6 seconds of following distance. Analyze whether this following distance meets the minimum formula requirements and identify what adjustments should be made for the speed differential and potential adverse factors.
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Question 22 of 50
22. Question
22. A driver transporting a load of logs on a flatbed trailer has secured the cargo using four stake pockets with stakes inserted, and has used chains wrapped around the log stack at multiple points. During the 50-mile cargo inspection, the driver notices one chain has loosened by approximately 2 inches. What specific requirements apply to log cargo securement under 49 CFR Part 393 Subpart J, and what action must the driver take?
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Question 23 of 50
23. Question
23. A commercial driver is preparing to make a right turn in a city environment. According to proper turn signal timing, when should the driver activate the turn signal?
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Question 24 of 50
24. Question
24. A driver needs to ensure adequate weight on the front axle of a tractor-semitrailer for safe operation. What is the primary reason front axle weight is critical for CMV safety?
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Question 25 of 50
25. Question
25. You are driving a tractor-semitrailer in heavy fog on a highway. Visibility is reduced to approximately 200 feet. Other vehicles are traveling at reduced speeds, and you need to navigate safely through this condition. What is the correct headlight usage for driving in fog?
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Question 26 of 50
26. Question
26. What organization publishes the North American Standard Out-of-Service Criteria that determines when a commercial motor vehicle cannot be legally operated?
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Question 27 of 50
27. Question
27. You are driving a CMV with air brakes on a highway when you notice the air pressure gauge reading has dropped from 120 PSI to 95 PSI over the past 10 minutes without any heavy braking. The low-pressure warning light has not activated. What should you do?
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Question 28 of 50
28. Question
28. What is the minimum tread depth required for steer axle tires on a commercial motor vehicle according to federal regulations?
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Question 29 of 50
29. Question
29. While driving at night on an interstate highway, you notice an oncoming vehicle approaching in the opposite lane approximately 600 feet away. Your headlights are currently set to high beams. What should you do?
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Question 30 of 50
30. Question
30. What is the FIRST step a driver must take when uncoupling a tractor from a trailer?
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Question 31 of 50
31. Question
31. A driver is traveling on a rain-slicked highway at 50 MPH when a sudden braking situation occurs. The driver brakes firmly and feels the tractor beginning to slide sideways while the trailer continues pushing forward—a jackknife is starting. Which immediate action should the driver take to attempt recovery?
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Question 32 of 50
32. Question
32. A driver operating a loaded tractor-semitrailer notices smoke coming from under the hood area and smells burning material. The driver pulls to the shoulder and stops. What is the correct sequence of actions for responding to a vehicle fire?
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Question 33 of 50
33. Question
33. A driver completes a pre-trip inspection and discovers that the slack adjuster on the left front brake shows push rod travel of 1.5 inches. The driver documents this on the DVIR but decides to proceed with the trip because the carrier’s maintenance department is closed and cannot certify repairs until Monday. Which analysis correctly describes the regulatory and safety implications of this decision?
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Question 34 of 50
34. Question
34. A driver with a Class B CDL is performing a pre-trip inspection on a straight truck with air brakes. Which inspection component would NOT be part of this Class B vehicle’s pre-trip procedure compared to a Class A combination vehicle inspection?
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Question 35 of 50
35. Question
35. When making a right turn with a tractor-semitrailer, what is the correct procedure to prevent the trailer from off-tracking into the curb or adjacent lane?
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Question 36 of 50
36. Question
36. During trailer coupling verification, a driver notices that the rubber seal inside the emergency (blue) glad hand connector is cracked and partially deteriorated. The seal is still present but shows visible wear. The driver connects the air lines and performs a visual check. What is the correct action for this condition?
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Question 37 of 50
37. Question
37. When did the FMCSA ELD mandate become effective for most commercial motor vehicle drivers required to keep Records of Duty Status (RODS)?
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Question 38 of 50
38. Question
38. How far ahead should a commercial driver look while driving at highway speeds to maintain adequate visual search and anticipate potential hazards?
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Question 39 of 50
39. Question
39. A driver is approaching a 90-degree right turn in a residential area with parked cars along the curb. The driver operates a 65-foot tractor-semitrailer combination. Analyze the situation and determine which approach minimizes the risk of trailer off-tracking into the sidewalk area while avoiding conflict with oncoming traffic.
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Question 40 of 50
40. Question
40. What is the primary reason commercial drivers should always back toward the driver’s side when possible?
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Question 41 of 50
41. Question
41. A CDL driver receives an L restriction on their license. What does this restriction indicate, and how can it be removed?
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Question 42 of 50
42. Question
42. A CDL applicant undergoes a DOT physical examination. The applicant’s uncorrected vision is measured at 20/60 in the right eye and 20/80 in the left eye. When wearing corrective lenses, the applicant’s vision improves to 20/40 in each eye. Based on 49 CFR Part 391 vision requirements, is this applicant medically qualified to operate a CMV?
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Question 43 of 50
43. Question
43. During the walk-around inspection, what color are the rear clearance lamps and identification lamps required to be on a commercial motor vehicle?
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Question 44 of 50
44. Question
44. A driver is approaching a tight right turn with a guardrail on the right side of the road. There is oncoming traffic in the opposite lane. The driver must decide how to execute this turn safely. Which analysis best describes the correct approach?
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Question 45 of 50
45. Question
45. A driver couples a tractor to a semitrailer and performs the tug test. When pulling forward gently against the trailer brakes, the trailer moves forward several inches and the driver hears a clunk from the fifth wheel area. The driver stops, inspects the fifth wheel, and finds that the locking lever is not fully in the locked position. What is the most likely cause of this coupling failure, and what should the driver do?
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Question 46 of 50
46. Question
46. What is the maximum acceptable air pressure drop during a static leak test with the engine off and parking brake applied for a single vehicle?
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Question 47 of 50
47. Question
47. A driver needs to back a tractor-semitrailer into a dock located at the end of a narrow alley. The alley is approximately 12 feet wide with limited visibility on both sides. The dock entrance faces the alley directly. Analyze the situation and determine the safest backing approach.
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Incorrect
Question 48 of 50
48. Question
48. A commercial driver is approaching a four-way intersection where their traffic light has just turned yellow. The intersection is clear, and the driver estimates they are 100 feet from the stop line traveling at 35 mph in a fully loaded truck. The driver knows they can stop safely. What should the driver do?
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Question 49 of 50
49. Question
49. You are approaching a railroad crossing in a low-clearance CMV (vehicle bottom clearance of 8 inches). The crossing has a steep approach on both sides, and you observe that the tracks sit higher than the road surface. You are currently in a line of vehicles waiting to cross. Which statement BEST describes your space management concern at this crossing?
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Question 50 of 50
50. Question
50. A driver is descending a long, steep grade with a fully loaded combination vehicle. The driver notices the brake pedal feels “spongy” and requires more pressure to achieve the same braking effect, even though the air pressure gauge shows normal pressure. The driver continues using the brakes heavily. What is happening, and what is the correct response?
