Alcohol test for driving the morning after is inaccurate

AN alcohol calculator created to work out if drivers are still over the limit the morning after drinking is not accurate or effective, experts have warned.

Confused.com’s Morning After Calculator works out how long alcohol may take to leave a person’s system, telling them what time they are likely to be safe to drive after a night of drinking.

The calculator was promoted by the comparison site ahead of Black Friday, the last Friday before Christmas which is notorious for high numbers of people going out to bars and clubs.

Users can input their sex, weight, when they last had a drink, and the number of drinks consumed, which is worked out in terms of pints of beer and glasses of wine or spirits. It does not include the percentage of alcohol in each drink.

The calculator carries a warning above it that says: “Please don’t use our morning after calculator in the place of sensible caution.”

But leading road safety campaigners have branded the tool “irresponsible”, warning that drivers using it may inadvertently drive under the influence.

Motorists who drive or attempt to do so while over the limit can face up to six months in prison, an unlimited fine and a driving ban of at least a year.

The drink-driving alcohol limit for drivers is split into blood, breath and urine across England, Wales and Northern Ireland. The limit is 80 milligrams of alcohol per 100 millilitres of blood, 35 micrograms per 100 millilitres of breath and 107 milligrams per 100 millilitres of urine.

John Scruby, spokesman for Campaign Against Drink Driving, said: “It’s irresponsible. If somebody relies on this then that is a big risk they are taking.

‘The only way to ensure you’re not over the limit in the morning is to not drink the night before’

Mr Scruby, who was a traffic officer for 25 years, said: “There is no calculator in the world that could measure this, the only calculator is the legal limit, a safe limit and that limit is zero.”

Others raised concerns that the calculator failed to take into account alcohol percentage levels in drinks.

Nicholas Lyes, director of policy and standards at IAM RoadSmart said it should be taken with a “pinch of salt”.

“The only way to ensure you’re not over the limit the following morning is to not drink the night before.”