Drink driving

Alcohol: the second leading cause of fatal accidents

Alcohol remains one of the leading causes of death on the road. In France, roughly one fatal accident in three involves a driver whose blood alcohol level exceeds the legal limit. Studies show that the risk of being responsible for a fatal accident is on average multiplied by 18 for a drink driver, with a dose effect: the more you drink, the more the risk increases exponentially.

What is blood alcohol level?

Blood alcohol level refers to the amount of pure alcohol present in the blood. It is measured in two ways: in grams per litre of blood (g/L) or in milligrams per litre of exhaled air (mg/L). The conversion is straightforward: the exhaled air reading is half the blood reading.

Legal limits you need to know

For a driver holding a full licence, it is prohibited to drive with a level equal to or above 0.5 g/L of blood (i.e. 0.25 mg/L of exhaled air). In practice, two standard drinks are generally enough to reach this limit.

For drivers in the probationary period (licence held for less than 3 years, or 2 years with accompanied driving), the limit is lowered to 0.2 g/L of blood (i.e. 0.10 mg/L of exhaled air). This limit is not set at zero because small traces of alcohol can come from food (certain pastries, for example). But after just one drink, this limit is exceeded: the rule is simple — do not drink.

One glass = one standard measure

In bars and restaurants, each glass is calibrated to contain the same amount of pure alcohol: roughly 10 grams. A half-pint of beer (25 cL at 5%), a glass of wine (10 cL at 12%), a glass of champagne (10 cL) or a shot of whisky (3 cL at 40%) all contain 10 g of alcohol. This corresponds to roughly 0.20 g/L in the blood for a 70 kg man, and 0.30 g/L for a 60 kg woman.

The effects of alcohol on driving

The effects appear from the very first drink and affect all of the driver's abilities. Alcohol narrows the field of vision, disrupts the estimation of distances and speeds, lengthens reaction time, reduces alertness and the coordination of movements. It also increases sensitivity to glare, particularly at night, and reduces the perception of the colour red, making Stop signs and red lights harder to see.

Psychologically, alcohol causes an overestimation of one's own abilities and an underestimation of danger. This is in fact one of its earliest effects: making you believe you can still drink and drive without a problem.

Eliminating alcohol: only time works

After consumption, the blood alcohol level reaches its peak roughly 30 minutes later on an empty stomach, and roughly 1 hour later during a meal. The liver then eliminates alcohol at an average rate of 0.10 to 0.15 g/L per hour. To eliminate two drinks, you therefore need to allow 4 to 6 hours.

Checks and penalties

The police first use a breathalyser (chemical or electronic) for a screening test. If the crystals turn green (positive result), a precise measurement is taken with an evidential breath analyser or a blood test.

Screening is automatic in the case of an injury accident or a serious offence. It may also be carried out randomly during preventive checks.

Between 0.5 and 0.79 g/L of blood, it is an offence: 6 points deducted, a fine of 135 euros, possible licence suspension and vehicle immobilisation. From 0.8 g/L, it becomes a criminal offence: a fine of up to 4,500 euros, 6 points deducted, immediate licence retention (which may lead to cancellation), vehicle immobilisation and a possible prison sentence of up to 2 years.

For probationary licences, from 0.2 g/L: 6 points deducted (which means losing the licence in the first year), a fine of 135 euros and vehicle immobilisation.

Planning the journey home

Several solutions exist to avoid driving after drinking: designate a sober driver (the 'designated driver'), use public transport or a taxi, plan to sleep over at a friend's house or a hotel, or simply wait for the alcohol to be eliminated by checking your level with a breathalyser.

The alcohol interlock device (EAD)

This device requires the driver to blow into it before starting the engine. If the test is positive, the engine will not start. A second breath sample is required 5 to 30 minutes after starting, whilst fully stopped. The EAD may be imposed by the prefect on a driver whose licence has been suspended, or as an additional penalty. Its installation is always at the offending driver's expense.