The legal limit for driving is 80mg of alcohol per 100ml of blood. There is no failsafe guide as to how much you can drink and stay under the limit. Any alcohol, even a small drink will impair driving ability and the only safe course is not to drink any alcohol prior to driving.
Alcohol is quickly absorbed into the bloodstream, this affects the brain and impairs driving ability. The following lists the major changes that occur to the human body as a result of alcohol consumption.
At blood alcohol level 20-50mg/100ml
Inability to see or locate moving lights correctly. Problems in judging distances. Tendency to take risks.
At blood alcohol level 50-80mg/100ml
Impaired judgement of distances. Impaired adaptability of eyes to changing light conditions. Impaired sensitivity to red lights. Severe impairment of ability to react and of concentration.
At blood alcohol level 80-120mg/100ml
Euphoria setting in - overestimation of one's own abilities. Impairment of peripheral vision. Increased impairment of eyes' reaction to light and dark. Impaired perception of obstacles and deterioration of ability to assess dimensions.
At blood alcohol level 120-140mg/100ml
Beginning of complete unfitness to drive. Serious impairment of concentration and vision. Very delayed and impaired reactions. Major orientation problems.
Getting rid of alcohol is a much slower process requiring hours rather than minutes. There is no way of speeding up alcohol elimination. A person can still be over the legal limit the morning after an evening's drinking.
Nearly one in seven of all deaths on Scottish roads involve drivers who are over the legal limit. The risk of being involved in an accident increases rapidly with the amount of alcohol consumed.
Causing death by careless driving whilst under the influence of drink or drugs will result in a maximum 10 year jail sentence and a minimum 2 year driving ban.
Driving or attempting to drive whilst above the legal limit or failing to provide a specimen will result in a maximum 6 month jail sentence & fine of £5,000 plus at least a 12 month disqualification.
Other consequences of a drink drive conviction include a criminal record, possible loss of livelihood, increase insurance costs, extreme difficulty in hiring a car for around 10 years, legal expenses, social stigma.