Data sheet Steep hill road signs
Some of the signs used on Britain’s roads give advance warning of steep hills.
The sign is a red triangle (as are all road warning signs) with a slope going
up or down, and a numerical expression.
If the road goes downhill, the slope on the sign goes down from left to right.
If the road goes uphill, the slope on the sign goes up from left to right.
The approximate gradient of the slope is shown on the sign, either
• as a percentage, such as 10% or 14%, or
• as a ratio, for example 1 : 7 (written as 1 in 7 on older signs)
A gradient of 1:10 (1 in 10) means that for every 10 metres of forward travel
on the hill, the height changes by about one metre.
10
1
One tenth is 10%, so the sign above is for a 1 in 10 downhill slope.
A hill of 1 : 20 means that there will be a change in height of one metre for
every 20 metres of forward travel.
One twentieth is 5%, so a gradient of 5% indicates a 1 in 20 slope.
20
1
