Rolling resistance (%)

Road surface conditions (built from unbound gravel materials)

2

Strong layerworks and hard, compacted well-built and maintained road, no tire penetration/deflection discernable

2 - 3

Intermediate strength layerworks, compacted, well-built and frequently maintained road, with minimal (<25 mm) tire penetration/deflection

3 - 5

Weak layerworks or surfacing material, 25 - 50 mm tire penetration/deflection, rutted and poorly maintained

5 - 8

Weak layerworks or surfacing material, 50 - 100 mm tire penetration/deflection, rutted and poorly maintained