DTT HGV Motorway Driving and CPC Requirements 4

Question 1

How do weather conditions affect the safe speed for a truck on a motorway?

Accepted Answer

In adverse weather, the safe speed is much lower than the speed limiter setting — the driver must always drive to the conditions

Answer

The speed limiter sets a maximum — not a safe speed in all conditions. In rain, fog, ice, or strong winds, the safe speed may be well below 90 km/h. Driving at the limiter's maximum in poor conditions is a serious offence.

Question 2

What is the 'blind spot' problem specific to trucks and buses, and how should drivers manage it?

Accepted Answer

Large vehicles have much larger blind spots than cars — especially nearside, behind, and in front. Drivers must use mirrors, cameras, and physical checks to manage these areas

Answer

Trucks and buses have very large blind spots — especially on the nearside (left), directly behind, and immediately in front of the cab. Cyclists and pedestrians can be invisible in these zones. Regular mirror scanning and nearside cameras are essential.

Question 3

What does 'vehicle stability control' (ESP/ESC) do on a heavy vehicle?

Accepted Answer

Detects impending rollover or loss of lateral stability and automatically reduces engine torque and applies individual wheel brakes to stabilise the vehicle

Answer

Electronic Stability Programme (ESP) / Electronic Stability Control (ESC) detects when the vehicle is about to roll or go into a skid and intervenes automatically — reducing engine torque and selectively applying brakes to correct the trajectory.

Question 4

What is the purpose of the 'Advanced Emergency Braking System' (AEBS) on trucks?

Accepted Answer

AEBS automatically detects vehicles or obstacles ahead and applies emergency braking if the driver does not respond — preventing or mitigating rear-end collisions

Answer

AEBS (mandatory on new trucks since 2015) uses radar and cameras to detect forward collision risk. It first warns the driver, then if no response, automatically applies emergency braking to prevent or reduce the severity of a collision.

Question 5

What is the importance of route planning for a heavy vehicle operator?

Accepted Answer

Identifying low bridges, weight-restricted roads, unsuitable road widths, and hazardous bends before departure prevents incidents and prohibitions

Answer

Route planning is essential for heavy vehicles — low bridges cause catastrophic impacts, weight-restricted roads carry prosecution risk, and some roads are physically impassable. Both operators and drivers share responsibility.

Irish DTT Truck/Bus Practice Test

Irish DTT Truck/Bus Practice Test

DTT HGV Motorway Driving and CPC Requirements 4