Sorry, that link doesn't seem to work. Anyway, the article says;
"More than half of London's motorists are confused by road signs, a survey has found.
Some motorists thought a slippery road sign meant they should be cautious of drunk drivers, an insurance firm said.
The survey also showed 50% of drivers did not know the sign for risk of ice and some thought a side winds warning sign indicated a kite-flying area.
More than half of London's drivers admitted they had not checked a Highway Code since passing their test.
The survey, carried out by Prudential Car Insurance, marks the 70th anniversary of the driving test."