The number of alcohol units you can safely and legally drive on depends on the specific legal limits for blood alcohol concentration (BAC) which vary by location and individual factors. Here are the key points for the UK as an example:
- In England, Wales, and Northern Ireland, the legal BAC limit is:
- 35 micrograms of alcohol per 100 ml of breath
- 80 milligrams of alcohol per 100 ml of blood
- 107 milligrams of alcohol per 100 ml of urine
- In Scotland, these limits are lower:
- 22 micrograms per 100 ml of breath
- 50 milligrams per 100 ml of blood
- 67 milligrams per 100 ml of urine
- The UK Department for Transport recommends:
- Men should drink no more than 2-3 units of alcohol if they plan to drive
- Women should drink no more than 1-2 units of alcohol if they plan to drive
- One unit of alcohol is defined as 8 grams or 10 ml of pure alcohol.
- Examples of units in common drinks:
- A pint of 3.8% ABV beer is about 2.2 units
- A 125 ml glass of wine (11% ABV) is about 1.5 units
- A single 25 ml shot of spirits (40% ABV) is 1 unit
- The actual effect of alcohol and how many units you can consume while remaining under the legal limit varies greatly depending on your gender, weight, age, metabolism, food consumed, and other factors.
- Because there is no exact way to calculate the safe number of units for every person, the safest choice is to avoid alcohol if you plan to drive.
In summary, you might drive under the influence of roughly 2-3 units (men) or 1-2 units (women) in the UK before reaching the legal limit, but this is only a rough guideline and varies widely by individual and situation. The safest advice is not to drink before driving at all to ensure safety and legality.
