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SGI Commercial Practice Test 2026 – Free Saskatchewan Commercial Questions

Original questions written from the official Saskatchewan handbook, with an explanation for every answer.

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  • 254 questions
  • 11 practice tests
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Practice test 1 · Question 1Score 0/0

The supply line to the trailer ruptures. What happens to the trailer brakes?

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All Saskatchewan Commercial practice tests

11 sets of 25 questions. Each set is fixed, so you can repeat it until you score 100%.

Exam facts

Key facts: Saskatchewan Commercial Knowledge Tests (Class 1–4 and Air Brake)

Free practice tests for SGI's commercial knowledge exams: the Class 1, 2, 3 and 4 papers and the air brake (A endorsement) paper. Every question is original, written from the SGI Professional Driver's Handbook (2026-27) and the SGI Air Brake Manual (2025-26), explains why the right answer is right, and names the handbook page it comes from. No sign-up, no limit on attempts, and your progress stays on your own device.

SGI publishes how many questions are on each paper: Class 1 has 20, Class 2 has 15, Class 3 and Class 4 have 10 each, and the air brake paper has 18. Our mock exam follows exactly that blueprint, so you practise the 73 questions a Class 1 driver with an air brake endorsement writes beyond the Sign and Basic papers. Practise one class at a time with the pages below, then take full mock exams.

What the test covers

Topics and question bank

Every question is tagged to one topic from the official handbook. Pick a topic to drill just that area.

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Sample Saskatchewan Commercial questions

Tap a question to see the answer. The full interactive test is at the top of the page.
  1. 1The supply line to the trailer ruptures. What happens to the trailer brakes?
    • A. They go into an emergency application at once
    • B. They release completely
    • C. They wait until the next foot application
    • D. They work only with the hand valve

    A supply-line rupture triggers the relay emergency valve so the trailer brakes apply right away, and the trailer-supply valve closes to protect the tractor's air.

  2. 2In winter, how often should you drain the air tanks?
    • A. Only when the low air warning sounds
    • B. Once a month during cold weather
    • C. Daily, leaving them empty when not in use
    • D. Only when water is seen at the gladhands

    Drain air tanks daily and leave them empty when the vehicle is not in use, so moisture cannot freeze in the system.

  3. 3Your truck has an air dryer. Do you still need to drain the reservoirs?
    • A. Only if the air dryer's own warning light comes on
    • B. Only once a month during the summer driving season
    • C. Yes, daily; the dryer does not remove all moisture
    • D. No, the dryer removes all the water

    An air dryer removes most moisture and helps prevent freeze-ups, but not all of it, so reservoirs must still be drained daily when in use.

  4. 4One wheel's brake is poorly adjusted. What happens to the other brakes?
    • A. They lock up at the first application
    • B. They release slightly to balance the load
    • C. They do more than their share and may overheat
    • D. They keep working exactly as before

    If one or two brakes are out of adjustment, the others must do extra braking, which can create more heat than their drums can absorb, leading to damage or failure.

  5. 5How is a straight truck designed to carry its cargo weight?
    • A. All of it on the rear tires
    • B. About 50% on each axle
    • C. About 90% on the rear tires, 10% on the front
    • D. About 70% on the front, 30% on the rear

    The average truck design puts about 90% of the cargo on the rear tires and 10% on the front. A trailer's cargo should be split equally between its tires and the fifth wheel.

  6. 6A driver has taken a sedating medication and then drinks a beer. How do the effects combine?
    • A. They add up to the two amounts together
    • B. They multiply, causing far more impairment
    • C. The medication cancels out the alcohol
    • D. Only the alcohol affects driving ability

    With another drug already in the system, alcohol's effect on the brain is multiplied rather than simply added, so impairment is far greater.

  7. 7Your load overhangs the truck body. What marking is required at night?
    • A. A red flag tied to the end of it
    • B. A red light at the end of the overhang
    • C. A white reflector on each side of the overhang
    • D. An amber flashing light on the cab

    Any overhang needs a red flag at its end between sunrise and sunset and a visible red light at its extreme rear during night hours.

  8. 8At what pressure must the governor cut out the compressor?
    • A. Between 80 and 100 psi
    • B. Between 60 and 70 psi
    • C. Exactly 150 psi
    • D. Between 120 and 145 psi

    The governor unloads (cuts out) the compressor at 120–145 psi (828–1,000 kPa) and cuts it back in at no less than 100 psi.

  9. 9What vehicle must you bring for a Class 1 road test?
    • A. A school bus with air brakes
    • B. A three-axle power unit and a 48 ft or longer trailer
    • C. A two-axle truck towing any trailer heavier than 4,600 kg
    • D. A tandem tractor without a trailer

    For the Class 1 road test you must provide a three-axle power unit and a trailer of at least 48 ft, and arrive with a driver licensed for that class.

  10. 10Why might badly adjusted brakes go unnoticed?
    • A. They only fail in warm weather
    • B. The low air warning hides them
    • C. They make the pedal feel harder
    • D. They seem fine under light braking

    Even grossly maladjusted brakes seem to work under light braking; the danger appears only under moderate to heavy braking.

About the test

About the Saskatchewan Commercial Knowledge Tests (Class 1–4 and Air Brake)

Saskatchewan uses a classified licence system run by SGI. Class 1 is for power units pulling semi-trailers and trucks towing more than 4,600 kg. Class 2 is for buses seating more than 24 passengers, Class 3 for trucks with more than two axles, and Class 4 for buses seating 24 or fewer, taxis, rideshare vehicles and ambulances used for hire. Each higher class also covers the classes below it. Any vehicle with air brakes needs the A endorsement, except farm-licensed Class 3 or 5 trucks and trucks with air-over-hydraulic brakes.

Every commercial applicant writes SGI's Sign paper (30 questions) and Basic Class 5 paper (20 questions), which come from the Saskatchewan Driver's Handbook; you can practise those with our SGI Class 7 practice test. On top of them, Class 4 adds the Class 4 paper; Class 3 adds the Class 3 and 4 papers; Class 2 adds the Class 2, 3 and 4 papers; and Class 1 writes all four. The air brake paper is a separate 18-question exam, followed by a practical demonstration on equipment you provide. Knowledge exams can be attempted only once per day.

SGI says the papers are based on the Professional Driver's Handbook, the Saskatchewan Driver's Handbook and the Air Brake Manual, but it does not publish which chapters each paper draws from. We grouped our topics by the vehicles each class covers: general professional driving, inspections, taxis and emergency vehicles under Class 4 (which every commercial driver writes); weights, loads, turning and dangerous goods under Class 3; buses and school buses under Class 2; and coupling and tractor-trailer handling under Class 1. Treat this as a study plan, not as SGI's official paper content.

Before any testing you must be at least 18, not a novice driver, and have a Commercial Driver's Licence Medical Report approved by SGI. Class 1 applicants must also finish Mandatory Entry-Level Training of at least 121.5 hours before the road test. Road tests and trip inspections are done in a vehicle you provide; Class 1 adds offset and alley dock backing and coupling and uncoupling a trailer.

SGI does not publish a pass mark or time limit for the commercial papers. Our mock exam uses a practice standard of 80 per cent on each paper, because SGI marks each paper separately and you rewrite only the papers you fail. Confirm the current pass mark and fees with SGI or a motor licence issuer when you book. This site is independent and is not affiliated with SGI; passing our practice tests does not give you a licence or endorsement.

Study plan

How to prepare

  1. 1Download the free SGI Professional Driver's Handbook and Air Brake Manual. Every question here cites the handbook page it comes from, so you can check anything you get wrong.
  2. 2Work out which papers you need. Class 4 is Sign, Basic and Class 4; Class 1 is Sign, Basic and the Class 1, 2, 3 and 4 papers. Add the air brake paper if your vehicle has air brakes.
  3. 3Start with the Class 4 topics. Every commercial class writes the Class 4 paper, and they cover the everyday rules: driver condition, following distance, braking, parking, trip inspections and emergency vehicles.
  4. 4Make a list of the numbers SGI uses: 4,600 kg for towed units, the length-divided-by-three following count, 12.5 m, 23 m, 2.6 m and 4.15 m dimension limits, 11,794 kg for trip inspections, and the 100 m and 25 m school bus light distances.
  5. 5For air brakes, learn the pressures cold: governor cut-out 120–145 psi, cut-in no lower than 100 psi, low air warning at 60 psi, spring brakes fully applied at 20–45 psi, tractor protection at 20 psi, and 1 or 4 psi loss in a minute.
  6. 6Practise the air brake pre-trip test out loud, in order. The practical demonstration is done without a checklist, and you must adjust a manual slack adjuster and explain how automatic ones are checked.
  7. 7Take a full mock exam and look at your score on each paper, not just the total. Aim for at least 80 per cent on every section in two mocks in a row before you book.
  8. 8Book and pay on MySGI or with a motor licence issuer, bring your approved medical, and remember you can write a knowledge exam only once per day.

FAQ

Saskatchewan Commercial test questions people ask

How many questions are on the SGI Class 1 knowledge test?

SGI's Class 1 paper has 20 questions, but a Class 1 applicant also writes the Class 2 (15), Class 3 (10) and Class 4 (10) papers, plus the Sign (30) and Basic Class 5 (20) papers. That is 105 questions in six papers, or 123 with the 18-question air brake paper.

How many questions are on the SGI Class 4 test?

The Class 4 paper has 10 questions. Class 4 applicants also write the 30-question Sign paper and the 20-question Basic Class 5 paper, for 60 questions in total.

How many questions are on the SGI air brake test?

The written air brake paper has 18 questions. You must also complete a practical demonstration, without help or a checklist, on an air brake vehicle you provide, including adjusting a manual slack adjuster.

What is the passing mark for SGI's commercial knowledge tests?

SGI does not publish a pass mark in the Professional Driver's Handbook or the Air Brake Manual. Our mock exam uses 80 per cent on each paper as a practice standard. Confirm the current pass mark with SGI when you book.

Is there a time limit?

SGI does not publish a time limit for the commercial papers, so our mock exam is untimed. Practise until you can answer each question without guessing.

Do I need a medical before I can write the tests?

Yes. For Class 1 to 4, school bus and heavy trailer privileges, a Commercial Driver's Licence Medical Report must be submitted to and approved by SGI before any test is started.

Can I take the tests if I am a new driver?

No. You must be at least 18 and not a novice driver. Class 7 holders and Class 5 drivers with a Novice 1 or Novice 2 restriction cannot get Class 1 to 4, school bus or heavy trailer privileges.

Do I need training before the Class 1 road test?

Yes. Saskatchewan requires Class 1 Mandatory Entry-Level Training of at least 121.5 hours (47 classroom or online, 17.5 in the yard, 57 behind the wheel) before you can schedule the Class 1 road test.

What if I fail one paper?

SGI marks each paper separately, and knowledge exams can be attempted only once per day. Use our per-class practice pages to drill the paper you missed before you write it again.

Are these the real SGI test questions?

No. SGI's questions are not public. Every question here is original, written by us from the official SGI handbooks, and cites the page it comes from. We are not affiliated with SGI.

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