Northamptonshire Police say July sees rise in drink drive offences
The warning comes as research suggests a fifth of drivers are driving over the limit the morning after drinking.
Northamptonshire Police say this month they see an increase in drink driving offences.
The warning comes as new research reveals drivers still don't realise they could be over the limit the morning after a night out.
More than a fifth (21%) of motorists have drunk alcohol after 10pm when needing to drive before 9am the following morning, a new survey suggests.
Road safety charity IAM RoadSmart, which commissioned the poll, warned that drinking alcohol the night before getting behind the wheel can pose a "serious threat" because a "groggy head" means slower reaction times.
The survey of 1,072 UK motorists also indicated that 38% of people who have consumed several alcoholic drinks ahead of driving before 9am stopped drinking after 9pm.
Charity Drinkaware states that alcohol is removed from the body at a rate of one unit per hour, although this varies depending on a person's weight, liver health and metabolism speed.
Around three large glasses of wine or three pints of high-strength beer or cider is the equivalent of nine units.
The advices around unit's and hours is echoed by Northamptonshire Police's Inspector Sean Watters:
"Every unit of alcohol drunk the night before, from an hour after you stop drinking, give it an hour per unit that you've consumed.
"Because every case goes on an individual basis, some people have bigger builds, some people are taller, shorter, etcetera. But we all process one unit of alcohol per hour."
So the more drinks you have the longer you should leave it for the alcohol to leave your system before driving.
Inspector Watters says even if you feel better the morning after, driving whilst over the limit could cost you:
"If you're involved in road traffic collision the next morning, our standard procedure is to breathalyse people. Also if you commit what we call a moving traffic offence. So if you're caught on your phone or, you know, running a red light accidentally, you will be breathalysed. And especially if the officers got suspicion.
"Because people do smell of alcohol the morning after and it is evident, maybe not to them, but to an officer it's quite recognisable."
Someone consuming those drinks up to 10pm could still have alcohol in their body at 7am or later, IAM RoadSmart warned.
Nicholas Lyes, the charity's director of policy and standards, said: "Drink-driving is a killer, and drivers may be unwittingly getting into their vehicle in the morning unaware that they could be doing so illegally if they have been drinking alcohol the night before, posing a serious threat to the safety of others.
"Even if they are just inside the legal limit, the level of alcohol in their system will impair their reaction times.
"Moreover, consuming alcohol impacts on sleep quality."
Chief Constable Jo Shiner, the National Police Chiefs' Council lead for roads policing, said: "There is simply no excuse for getting behind the wheel when you are impaired through drink or drugs, and this includes the morning after.
"If you choose to do so you are putting your life and the lives of others at risk."
The survey also suggested nearly a third (31%) of drivers in the previous 12 months had been with a friend or relative who drank alcohol before getting into a vehicle.
Some 72% of this group warned them they should not drive, while 23% said they took no action.
Four out of five (81%) people polled said rehabilitation courses should become mandatory for anyone convicted of a drink-drive offence.
Currently the courses are sometimes offered in return for a shorter driving ban.
Driver and Vehicle Licensing Agency statistics previously obtained by the PA news agency revealed 27,837 British motorists were convicted of drink-driving multiple times in the 11 years to July 20 2024.
Some 372 were caught at least four times, including four who were prosecuted on seven occasions.
Latest Department for Transport (DfT) figures show an estimated 300 people were killed in crashes on Britain's roads involving at least one driver over the legal alcohol limit in 2022.
That was up from 260 the previous year and was the highest total since 2009 when 380 deaths were recorded.
Separate figures show there are more drink drive-related casualties in July than any other month of the year.
The drink-drive limit in England, Wales and Northern Ireland is 80mg of alcohol in 100ml of blood.
Nowhere else in Europe has a limit above 50mg/100ml.