DTT HGV Study Guide 2026

Everything you need to pass the DTT HGV exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.

DTT HGV exam key facts

There is no limit on how many times a candidate can take the Irish Driver Theory Test, but waiting at least 3 complete business days before re-sitting is strongly advised. Source
An Irish Driver Theory Test certificate is only valid for 2 years from the date of the test. Source

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📚 DTT HGV Topics to Study (43)

Coupling and Uncoupling Trailers · 7 cards Coupling and Uncoupling Trailers · 7 cards Coupling and Uncoupling Trailers · 7 cards Driver Hours – EU Regulations · 6 cards Driver Hours – EU Regulations · 6 cards Driver Hours – EU Regulations · 6 cards Driver Hours – EU Regulations · 6 cards Driver Hours – EU Regulations · 6 cards Driver Hours – EU Regulations · 6 cards Drivers Hours · 6 cards Drivers Hours · 6 cards Emergency Procedures · 6 cards Emergency Procedures · 6 cards Load Security · 6 cards Load Security · 6 cards Motorway Driving and CPC Requirements · 6 cards Motorway Driving and CPC Requirements · 6 cards Motorway Driving and CPC Requirements · 6 cards Motorway Driving and CPC Requirements · 6 cards Motorway Driving and CPC Requirements · 6 cards Motorway Driving and CPC Requirements · 6 cards Passenger Safety and Air Brakes · 6 cards Passenger Safety and Air Brakes · 6 cards Passenger Safety and Air Brakes · 6 cards Passenger Safety and Air Brakes · 6 cards Passenger Safety and Air Brakes · 6 cards Passenger Safety and Air Brakes · 6 cards Road Signs · 6 cards Road Signs · 6 cards Tachograph Rules · 6 cards

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✍️ Sample DTT HGV Questions & Answers

1. A driver starts a daily rest at 18:00. When is the earliest they can resume driving under a regular 11-hour daily rest?

✓ 05:00 the following morning (18:00 + 11 hours)

Regular daily rest is 11 consecutive hours. Starting rest at 18:00 means the earliest resume time is 05:00 (18:00 + 11 hours). The driver may not start driving before this time.

2. How does the air brake system maintain pressure during a long journey?

✓ An engine-driven compressor continuously tops up the air reservoirs as air is used during braking

An air compressor driven by the engine continuously replenishes the air reservoirs. A governor valve stops the compressor when maximum pressure is reached and restarts it when pressure drops — maintaining consistent operating pressure.

3. What is the importance of pre-journey route checks for hazardous roads or bridges for a truck driver?

✓ A bridge collapse or getting stuck under a low bridge can be fatal and career-ending — route checks prevent costly and dangerous incidents

Pre-journey route checks are essential. Low bridges (under 4.65m) cause catastrophic and sometimes fatal collisions. Weight-restricted bridges can collapse or lead to prohibition. GPS maps are not always current with restrictions.

4. What CPC training topic directly reduces fuel costs for a transport operator?

✓ Eco-driving and fuel-efficient driving techniques — proven to reduce fuel consumption by 10-15%

Eco-driving training is directly linked to fuel savings. Studies consistently show 10-15% fuel reduction when drivers apply eco-driving principles — a significant saving given that fuel is one of the largest transport operating costs.

5. What must a truck or bus driver do before joining a motorway from a slip road?

✓ Accelerate to match motorway traffic speed on the slip road, check mirrors and blind spots, and merge safely into a gap in the left lane

Use the full length of the slip road to reach motorway speed, carry out MSM routine (mirrors, signal, manoeuvre), check the blind spot, and merge smoothly into a gap. Merging slowly disrupts motorway traffic and is dangerous.

6. What is the maximum gross vehicle weight (GVW) for a standard rigid truck on Irish roads?

✓ 32 tonnes for a two-axle rigid (higher for multi-axle combinations up to 44 tonnes for articulated)

Weight limits depend on axle configuration. A two-axle rigid truck is limited to 18 tonnes. Articulated vehicles with 5 or more axles can reach 44 tonnes. The standard 6-axle artic limit is 44 tonnes.

🎯 Free DTT HGV Practice Tests

Coupling and Uncoupling Trailers · 7 questions Coupling and Uncoupling Trailers · 7 questions Coupling and Uncoupling Trailers · 7 questions Load Security · 6 questions Road Signs · 6 questions Vehicle Weights · 6 questions Road Signs · 6 questions Emergency Procedures · 6 questions Passenger Safety and Air Brakes · 6 questions Tachograph Rules · 6 questions

📖 DTT HGV Guides & Articles

Your DTT HGV Study Path

1. Learn with Flashcards → 2. Drill Practice Tests → 3. Take the Full Exam Simulation

🃏 DTT HGV Flashcards (261)

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How this page was made: written with AI tools and published by Nathan Beja, founder of Practice Test Geeks, who is responsible for its content. Exam facts are checked against the official sources listed below. Not reviewed by a subject-matter expert. Editorial policy

Sources & references

Exam facts on this page (fees, format, dates, passing scores) are checked against these official sources; the date is our last check. Editorial policy

theorytest.ie — Exam format, passing score, retake policy, score release, time limit, score validity, test delivery, eligibility, fees, exam information · verified Oct 2026