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 Topics to Study (43)
✍️ 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?
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 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?
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 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?
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?
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.