CPC Eco-Driving & Fuel Efficiency

Question 1

Which driving technique most significantly reduces fuel consumption on a long motorway journey?

Accepted Answer

Using cruise control to maintain a steady speed and anticipating traffic flow to avoid unnecessary braking

Answer

Driving at the maximum speed limiter setting of 56 mph throughout

Answer

Driving in a lower gear at higher revs

Answer

Using the air conditioning continuously

Question 2

How does tyre pressure affect fuel economy?

Accepted Answer

Under-inflated tyres increase rolling resistance, increasing fuel consumption by up to 3% per 10% under-inflation

Answer

Higher pressure reduces fuel economy

Answer

Pressure has no measurable effect on fuel use

Answer

Fully inflated tyres increase fuel use due to reduced traction

Question 3

What does 'anticipatory driving' mean in an eco-driving context?

Accepted Answer

Reading traffic situations well ahead and adjusting speed smoothly to avoid unnecessary stop-start driving

Answer

Looking 5 metres ahead and reacting to hazards at the last moment

Answer

Driving faster to complete the journey before traffic builds

Answer

Following closely to benefit from the slipstream of the vehicle ahead

Question 4

Idling the engine of an HGV for extended periods is discouraged because:

Accepted Answer

It wastes significant fuel (approximately 2 litres/hour), increases emissions and can cause engine carbon build-up

Answer

It damages the clutch

Answer

DVSA prohibits idling for more than 5 minutes

Answer

It depletes the DEF/AdBlue fluid rapidly

Question 5

What is the effect on fuel consumption of increasing motorway speed from 56 mph to 60 mph?

Accepted Answer

A significant increase of approximately 10-15% due to the cubic relationship between air resistance and speed

Answer

Negligible — less than 1% increase

Answer

A reduction in fuel use due to reduced journey time

Answer

An increase of 50% due to air resistance

Question 6

How does carrying excess payload weight above the planned load affect fuel consumption?

Accepted Answer

Every extra tonne increases fuel consumption by approximately 1-2%, increasing running costs and emissions

Answer

It reduces fuel consumption through improved grip

Answer

Weight has no measurable effect on fuel consumption

Answer

Only affects fuel consumption on hills