Research for Kwik Fit has revealed the average driver knows only 79% of UK road signs, with one in five signs a mystery.
For two in five drivers not being able to understand a sign or being confused over its meaning has led to problems on the road.
The most common mistakes due to misinterpreting road signs are breaking the speed limit (16%), braking suddenly (15%) and having to slow down, causing traffic to build up (9%).
Perhaps recognising the gaps in their knowledge, the majority of drivers believe that the driving theory and hazard perception tests should be retaken throughout people’s motoring lives, with more than half (53%) thinking it should be repeated at least once every twenty years.