When speaking of the ‘drink driving limit’ one should actually use the plural since there is more than one: one limit for alcohol in the breath, another for blood, and one for urine.
The current drink driving limits for England Wales and Northern Ireland have been in place since 1967 and are as follows:
- 35 micrograms of alcohol in 100 millilitres (ml) of breath;
- 80 milligrams of alcohol in 100 ml of blood; or
- 107 micrograms of alcohol in 100 ml of urine.
How many drinks does it take to be over the limit?
Simple answer is it depends. Everyone metabolises alcohol at a different rate. Your weight, gender and age affect this; as do your activity levels; whether you’ve eaten recently; whether you’re on medication; the type of alcohol you consume; and the speed you drink it.
Drinkdriving.org has created a Blood Alcohol Content calculator to help people assess how many drinks it takes to be over the limit. Please note, however, that the results of the calculator are not guaranteed to be accurate due to all the variables that come into play.
The safest amount of alcohol to consume before driving is none. Short of installing an alcolock , this is the only guaranteed way to be sure that you do not exceed the drink driving limit.
Is the limit strictly enforced?
Crown Prosecution Service guidance on drink driving offences states that although the prescribed breath alcohol limit is 35 mg/ml, generally a driver will not be prosecuted with a breath alcohol level of below 40 mg/ml. Unlike the breath alcohol limit, however, the blood and urine limits are strictly applied — people face prosecution for being only one milligramme over their respective legal limits.
Can I be charged with drink driving even if I am below the breath/blood/urine limit?
Yes. A person may be charged under Section 4 of the Road Traffic Act 1988 for driving, attempting to drive or being in charge of a mechanically propelled vehicle when unfit to drive through drink. A person is deemed unfit when their ability to drive is impaired. This can be proven through appearance and behaviour. No testing is required.
Can I rely on coffee or taking a cold shower to help me pass a test?
No. You should not rely on drinking coffee or taking a cold shower to lower the level of alcohol in your body or pass a drink driving test.
How long does it take to sober up?
As a general guideline, and subject to the factors listed above, a healthy person will process one unit of alcohol every hour. This means that following a night of heavy drinking a person may wake up and, although feel sober enough to drive, still be over prescribed alcohol limit.
Charged with drink driving
If you’ve been charged with a drink driving offence, you need to consider your position very carefully as the penalties can be severe. In every case, you are strongly advised to seek legal advice.