DTT HGV Vehicle Weights 2

Question 1

What is the maximum weight permitted on a tandem axle (two axles in a bogie) with air suspension?

Accepted Answer

20,000 kg for a driven tandem axle with air suspension

Answer

A tandem (bogie) drive axle with air suspension or equivalent is permitted up to 19,000 kg under standard EU rules, with some Irish permits allowing up to 20,000 kg on certain configurations. The air suspension allowance is higher than mechanical suspension.

Question 2

What are the consequences of driving an overloaded vehicle in Ireland?

Accepted Answer

Fixed charge penalties, court prosecution, increased insurance risk, and the vehicle may be immobilised until the excess load is removed

Answer

Overloading offences can result in fixed charge penalties, prosecution in court with significant fines, penalty points, vehicle detention until excess load is removed, and increased insurance premiums. Repeat offences carry heavier penalties.

Question 3

How does overloading affect a vehicle's braking performance?

Accepted Answer

Braking distances increase significantly as the brakes must absorb more kinetic energy, and brakes may overheat and fade

Answer

An overloaded vehicle has more momentum and kinetic energy, requiring greater braking force and longer distances to stop. Brakes can overheat under the additional strain, leading to brake fade. Overloading also affects steering and vehicle stability.

Question 4

What is the 'unladen weight' of a vehicle?

Accepted Answer

The weight of the vehicle when empty of payload, including the body, fuel, oil, water, spare wheel, and standard equipment

Answer

Unladen weight (also called 'kerb weight' or 'tare weight') is the weight of the vehicle in its normal operating condition without any payload. It includes the vehicle body, full fuel tank, oils, coolant, spare wheel, and standard equipment.

Question 5

What is the maximum permitted weight for a tri-axle group (three axles in a bogie)?

Accepted Answer

24,000 kg

Answer

Under EU and Irish regulations, the maximum permitted weight for a tridem axle group (three axles) is 24,000 kg (24 tonnes), subject to minimum axle spacing requirements between the outer axles.

Irish DTT Truck/Bus Practice Test

Irish DTT Truck/Bus Practice Test

DTT HGV Vehicle Weights 2