Body size is no guide to passing morning-after breathalyser
Tests show that height and weight of drinkers has little or no bearing on their fitness to drive the day after an alcohol-fuelled evening.
And 70 per cent believe gender is also a vital factor in determining whether someone is legally fit to drive, said the poll which was also conducted by breathalyser company AlcoSense.
The two organisations joined the Transport Research Laboratory for an experiment.
Tested the next morning, the woman was well below the permitted alcohol level while the man was over the limit.
The survey also found that 25 per cent of drinkers knock back lots of water before they go to bed, while eight per cent eat large quantities of food after a night's drinking.
Next day, six per cent have a big breakfast and drink lots of coffee before driving.
Simon Henrick of Direct Line said: "Drivers are taking a huge risk if they are relying on rough calculations and unproven theories to see whether they are safe to drive their car the morning after the night before.
"Our study shows that, despite what people may think, there is no magic equation to work out if you are safe to drive the following morning."