CPC Eco-Driving

Question 1

What is the most fuel-efficient way to accelerate in an HGV?

Accepted Answer

Accelerate smoothly and progressively, using the green band on the rev counter

Answer

Smooth, progressive acceleration within the green band (typically 1,000-1,500 rpm) is the most fuel-efficient approach. Aggressive acceleration wastes fuel and increases wear. Block gear changing (skipping gears) can also help when appropriate.

Question 2

How does anticipating traffic conditions ahead help reduce fuel consumption?

Accepted Answer

Reading the road ahead allows the driver to maintain momentum, reduce unnecessary braking and acceleration

Answer

By looking well ahead and anticipating traffic flow, traffic lights, roundabouts, and hills, drivers can maintain momentum, coast where appropriate, and avoid harsh braking followed by heavy acceleration. This 'smooth driving' approach can save 10-15% on fuel.

Question 3

What is the most fuel-efficient cruising speed for most HGVs?

Accepted Answer

Between 50-56 mph (the speed limiter range), as fuel consumption increases significantly above these speeds

Answer

Most HGVs are most fuel-efficient at steady speeds between 50-56 mph. Above this, aerodynamic drag increases significantly (doubling for every doubling of speed). The speed limiter (56 mph for most UK HGVs) effectively caps the maximum cruising speed.

Question 4

How does cruise control help with eco-driving?

Accepted Answer

It maintains a constant speed, preventing the driver from unconsciously varying speed, which wastes fuel

Answer

Cruise control maintains a steady speed, eliminating the small speed variations that occur during manual throttle control. This consistency reduces fuel consumption. However, it should be disengaged on hilly terrain where the driver can manage speed more efficiently.

Question 5

Why should unnecessary electrical loads be switched off to save fuel?

Accepted Answer

The alternator requires engine power to generate electricity — more electrical load means more fuel consumption

Answer

Every electrical system in the vehicle is ultimately powered by the engine via the alternator. Running unnecessary electrical loads (air conditioning, heated screens, extra lights) increases the load on the alternator, which requires more engine power and therefore more fuel.

DVSA UK Driving Theory Practice Test

DVSA UK Driving Theory Practice Test

CPC Eco-Driving