A tyre's rolling resistance score ranges from A to G. Over the life of the tyre, fitting an A rated tyre could save you up to 6 litres of fuel when compared to a G rated tyre.
The difference in braking distances between each grade is roughly 3m - an average car length. This makes average stopping distance between an A and G rated tyre 18m. That's 4 car lengths.
To achieve the best grade, a tyre’s noise level must be at least 3dB under the legal limit set by the EU.