Drinking & Driving

Drinking and Driving

Blood Alcohol Concentration (BAC)

 ·         BAC is the amount of alcohol in the blood stream

 ·         A BAC level of 0.5 means that an individual has 0.5 g of alcohol in his/her body for every 1 litre of blood

 ·         Taking a standard drink of 10g of alcohol, BAC will generally increase by 0.2-0.3 for women and 0.1-0.2 for men for each standard drink

 ·         A BAC will generally decrease by approximately 0.2-0.1 per hour (¾ to 1 standard drink, or 8 g of alcohol per hour)

 ·         The BAC will increase sharply when alcohol is consumed on an empty stomach

 

Absorption and metabolism of alcohol

After an alcoholic drink is consumed, the alcohol is absorbed rapidly from the stomach and intestine into the bloodstream. The blood alcohol level after drinking a specific number of drinks depends on the rate of drinking and the rate at which it is broken down in the liver by the enzyme alcohol dehydrogenase or ADH. The capacity of the liver to break down alcohol is limited, so if the liver has to handle more alcohol than its capacity for break down, the remaining alcohol will circulate in the blood to other organs and tissues of the body, such as the brain. Alcohol usually starts to affect the brain within about 5 minutes of being swallowed.

Even small amounts of alcohol can influence the ability to drive, so the only safe advice is to avoid any alcohol if driving. The influence of alcohol on individuals varies depending on:

 1.       body weight

 2.       gender (men process alcohol faster than women)

 3.       how fast you drink

 4.       metabolism

 5.       age and/or

 6.       conditions under which alcohol is consumed (i.e. with or without food).

For example, a woman’s BAC generally increases higher than a man’s since women tend to be smaller and have more fat tissue per kg body and less body water compared to men. Consequently, alcohol is more concentrated in the woman’s blood consuming the same amount of alcohol as a man. In addition, women have less of the enzyme that metabolizes alcohol in their stomach and liver.

Because of the multitude of factors that affect BAC, it is very difficult to assess the own BAC or impairment. Alcohol steadily decreases a person’s ability to drive a motor vehicle safely. Listed below are some of the common negative consequences following the consumption of alcoholic beverages.

 

How alcohol affects driving

 

Many of the functions that are needed to drive safely are affected when alcoholic beverages are consumed: the brain takes longer to receive messages from the eye; processing information becomes more difficult; and instructions to the body's muscles are delayed resulting in slower reaction times.

 

Blurred and double vision can also occur, which means the ability to see things correctly while driving is reduced. Individuals are also more likely to take potentially dangerous risks behind the wheel if they've been drinking alcoholic beverages.

 

Consequences on the psychomotor functions of the driver:

 ·        Coordination and capacity to react decrease

 ·       Capacity to judge speed, distance and the relative position of the vehicle is affected

 ·       Capacity to follow a trajectory or to face an unexpected event is affected

 

Consequences on the vision of the driver:

 ·         Field of vision is reduced and peripheral vision is altered

 ·         Recovery of sight after a flash is delayed

 ·         Even with low alcohol levels in the blood, the capacity to see, follow, and accommodate objects is deteriorated

 

Consequences for behaviour and attitude:

 ·         Alcohol may alter driving behaviour and reactions may become aggressive or neglectful

 ·         It may induce feelings of over-confidence, which can give rise to reckless decisions

  
Driving while either intoxicated or drunk is dangerous and drivers with high blood alcohol concentration (BAC) are at greatly increased risk of car accidents, highway injuries and vehicular deaths. It is recommended not to drive when drinking. In most European countries, the limit is usually 0.5 g per 1 l of blood. For novice drivers, in some countries, limit is 0  g.

An updated and comprehensive international BAC limits table can be found on the International Center for Alcohol Policies (ICAP) website. For more information and data on European Road Safety you can also visit the European Commission DG Mobility and Transport website.

 

The above summary provide an overview of the topic, for more details and specific questions, please refer to the articles in the database.

BACKGROUND: Road traffic crashes (RTCs) are among the eight-leading causes of death globally. Strategies and policies have been put in place by many countries to reduce RTCs and to prevent RTCs and related injuries/deaths. METHODS: In this review, we searched the following databases Ovid Medline, Embase, Cochrane Database of Systematic Reviews, Epistemonikos, Web of Science, and LILACS for reviews matching our inclusion criteria between periods January 1950 and March 2020. We did not apply language or publication restrictions in the searches. We, however, excluded reviews that focused primarily on injury prevention and reviews that looked at crashes not involving a motor vehicle. RESULTS: We identified 35 systematic reviews matching our inclusion criteria and most of the reviews (33/35) included studies…
BACKGROUND: Worldwide, alcohol-related road traffic accidents represent a major avoidable health risk. The aim of this study was to evaluate the accuracy of self-estimating the degree of acute alcohol intoxication regarding the legal driving limit, and to identify risk factors for misjudgement. METHODS: In this prospective randomised controlled crossover trial, 90 social drinkers (mean age 23.9 +/- 3.5 years, 50% female) consumed either beer or wine. Study group subjects were made aware when exceeding the legal driving limit (BrAC = 0.05%). Controls received no information about their BrAC. For crossover, beer or wine were consumed in the opposite order. RESULTS: 39-53% of all participants exceeded the legal driving limit whilst under the impression to be still permitted to drive. Self-estimation…
Alcohol is the most frequently detected substance in drivers involved in road traffic collisions. Given that up to 35% of fatal road collisions are alcohol-related, it is important to determine the influence of alcohol intoxication on driving-related skills. This review provides an updated and systematic evaluation of the available research concerning the effect of alcohol intoxication on cognitive functions critical for driving. Databases EBSCOhost, PsycInfo, PubMed, Scopus, Transport Research International Documentation (TRID) and Web of Science were searched for controlled trials examining the effect of alcohol on divided attention, executive functioning, perception, psychomotor skills, reaction time and/or vigilance. Fourteen studies met the inclusion criteria and were included in this review. We found that each of the cognitive domains assessed in…
BACKGROUND: Drink driving is an important risk factor for road traffic accidents (RTAs), which cause high levels of morbidity and mortality globally. Lowering the permitted blood alcohol concentration (BAC) for drivers is a common public health intervention that is enacted in countries and jurisdictions across the world. In Scotland, on Dec 5, 2014, the BAC limit for drivers was reduced from 0.08 g/dL to 0.05 g/dL. We therefore aimed to evaluate the effects of this change on RTAs and alcohol consumption. METHODS: In this natural experiment, we used an observational, comparative interrupted time-series design by use of data on RTAs and alcohol consumption in Scotland (the interventional group) and England and Wales (the control group). We obtained weekly counts of…
INTRODUCTION: The social influence on drunk driving has been previously observed in several countries. It is noteworthy, however, that the prevalence of alcohol in road fatalities is not the same in all countries. The present study aimed to explore whether cultural values and the number of roadside breath tests moderate the link between the perceived drunk driving of one's peers and self-reported behavior. METHODS: Based on the European survey SARTRE 4, the responses of 10,023 car drivers from 15 countries were analyzed. Two cultural values, "tradition" and "conformism," were identified as possibly being linked to social influence. Country scores for these values were taken from the European Social Survey. The number of random roadside breath tests per inhabitant was used…
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