Practice question

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

Negligible — less than 1% increase
A significant increase of approximately 10-15% due to the cubic relationship between air resistance and speed
A reduction in fuel use due to reduced journey time
An increase of 50% due to air resistance

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

The correct answer is shown above. Try the full quiz for additional practice.