Drink driving and the legal alcohol limit
Alcohol can slow you down and affect your body’s responses making your driving unsafe, putting you and others at risk of accidents
Are you planning a night out and don’t know whether to drive or take a taxi? Or having an after work drink and unsure if you could still drive?
It's important to remember that alcohol can slow you down and affect your body’s responses making your driving unsafe, putting you and others at risk of accidents.
While strict alcohol limits and drink driving penalties exist to ensure safe driving on the roads, it’s been estimated that between 2010 and 2017 there were 48,750 reported drink drive accidents and 1,870 reported deaths caused by drink driving accidents.
Many of the functions that we depend on to drive safely are affected when we drink alcohol:
You can also experience blurred and double vision, which affects your ability to see things clearly while you are driving. And you’re more likely to take potentially dangerous risks because you can act on urges you normally repress.
In England, Wales and Northern Ireland, the alcohol limit for drivers is 80 milligrammes of alcohol per 100 millilitres of blood, 35 micrograms per 100 millilitres of breath, or 107 milligrammes per 100 millilitres of urine.
In most other European countries, the limit is less, usually 50 milligrammes per 100 millilitres of blood.
The alcohol limit for drivers in Scotland has been different to the rest of the UK since 2014. The limit is 50 milligrammes of alcohol per 100 millilitres of blood, 22 micrograms of alcohol per 100 millilitres of breath, and 67 milligrammes per 100 millilitres of urine.
There is no fool-proof way of drinking and staying under the drink drive limit. The amount of alcohol you would need to drink to be considered over the driving limit varies from person to person.
Even small amounts of alcohol can affect your ability to drive so the only safe advice is to avoid any alcohol if you are driving.
Even small amounts of alcohol affect your ability to drive and the only safe advice is to avoid any alcohol if you are driving.
If the police want to investigate whether you are over the drink drive limit, they will carry out a screening breath test at the roadside. To do this, they will use a breathalyser.
If you fail this test, or if they have other grounds to believe that your driving was impaired through drink, you’ll be taken to a police station and given a final breath test. At the station you will need to provide two more breath specimens into a complex breathalyser.
The lower of the two readings is used to decide whether you are above the drink driving limit.
The police can carry out a breathalyser test if you have committed a moving traffic offence (such as banned turns or going through a red light) been involved in an accident, or have given the police grounds to believe you are over the limit.
The police are allowed to stop any vehicle at their discretion, and will often set up drink driving check points over periods such as Christmas and New Year’s Eve.
Drunk drivers face a number of penalties depending on the seriousness of their offence. Anyone caught over the legal alcohol limit when driving may be banned from driving for at least 12 months, and face an unlimited fine. You may also be sent to prison for up to six months. Imprisonment, the period of disqualification, size of fine and penalty points depend on the seriousness of the offence.
 Department for Transport. (2019). Estimated number of reported drink drive accidents and casualties in Great Britain: 1979 – 2017. RAS51001. [Dataset]. Available at: https://www.gov.uk/government/statistical-data-sets/ras51-reported-drinking-and-driving. [Accessed 20 November 2019].
 Valenzuela, C.F. (1997). Alcohol and neurotransmitter interactions. Alcohol Health and Research World, 21, 144-148.
 European Transport Safety Council. Blood alcohol content (BAC) drink driving limits across Europe. [Online]. Available at: https://etsc.eu/blood-alcohol-content-bac-drink-driving-limits-across-europe/. [Accessed 20 November 2019].