Alcohol and driving

Alcohol is a psychodepressant drug that, even at low doses, influences adversely driving, as it disturbs the skills of the driver.

It is probably the most important risk factor for suffering a traffic accident.

It must be highlighted that the alcohol amounts taken do not affect all people equally.

The effects of alcohol depend of:
- Personal conditions such as age, habit, and custom.
- Physical constitution of the driver, as the greater the weight, the greater the amount of alcohol to be taken to achieve the same intoxication level.
- Modalities of ingestion, such as the quantity of drink, its concentration, fasting or during meals, time or rate of consumption of the beverage, or that the alcohol is gasified or hot, as these conditions enhance the fast appearance of alcohol in blood.

Alcohol is a toxic substance that affects the central nervous system and always has depressant effects, though it first occurs as an apparent stimulation by an excitement condition, and subsequent sedation.

Symptoms according to blood alcohol rate

From 0.3 to 0.5 g/L, it is the beginning of the risk area

Emotional excitability, reduction of mental acuity and of the ability to reason.
Relaxation and sensation of well-being, eye movement impairment, distortion of distances or “tunnel effect”, and weakness in the perception of mobile lights.

From 0.5 to 0.8 g/L

Slow general reaction and onset of motor disturbance, with loss of the ability for concentration and intuition and lack of coordination
Visual disturbances and equilibrium disorders
Poor perception of the red light.
Euphoria, optimism, and reduced inhibition and emotional instability, with overestimated self ability and desire to express it
Excess self-confidence not respecting signals.
Onset of impulsiveness and aggressiveness when driving.

From 0.8 to 1.5 g/L

Significant intoxication state, highly disturbed reflexes, and slow response.
Loss of accurate control of movements and serious coordination problems.
Expressive and motor awkwardness.
Reduction of intellectual performance, with difficulty in mental activities, such as memory and ability for judgment.
Appearance of emotional aggressiveness states in case of setbacks. Reckless driving.
Marked reduction of alertness and perception of risk.

From 1.5 to 2.5 g/L

Clear intoxication with possible narcotic effects and confusion.
Unpredictable behavioral changes and marked mental confusion.
Very blurred vision, hesitating attitude and lack of movement coordination.

Over 2.5 g/L

Severe intoxication, stupor with analgesia and progressive unconsciousness.
Suppression of reflexes, paralysis, and hypothermia. It can result in coma.
Inability to drive.

Once this alcohol levels are reached in blood, the effects are similar for all people, regardless of the amount taken and depending on its blood concentration.

The proportionality between concentrations and effects is affected by the development of tolerance, so motor, sedative, anxiolytic and anesthetic effects of ethanol decrease in intensity after long-term alcohol consumption.

Long-term alcohol consumption causes digestive, cardiac, and liver disorders, loss of memory, paranoia, visual and reflex disturbances, etc., that are in many cases permanently disabling for driving.

Metabolism of alcohol and its influence on driving

Ethyl alcohol is distributed uniformly throughout the body tissues and fluids, except for fat.
Liver is mainly in charge of clearing alcohol.
However, the alcohol disintoxication process is much longer that in intoxication.
For instance, in a healthy man of 70 kilograms weight exceeding the limit of 0.5 g/L of alcohol in blood, nearly 5 hours will be required to eliminate alcohol completely, as the elimination rate is between 0.15 and 0.20 g/L per hour.
For 1.2 g/L, complete elimination would take about 8 hours.
Some alcohol consumptions, that in normal circumstances could be rated risk-free, can be very dangerous in situations where the person must drive, pilot or handle machines.
“Anti-hangover” brews mask dangerously the effects, but do not remove them.

Advice on alcohol and driving

Alcohol is a toxic substance that affects the central nervous system preventing from safe driving. Therefore, if you are going to drive, do not drink alcohol.