According to a January 2018 Forbes article, "Despite decades of progress, alcohol-impaired driving remains the greatest single cause of motor vehicle deaths in the U.S., exceeding those from distracted driving and driving while under the influence of drugs".1 And even in the United Kingdom where rates are even lower, around 14% of all deaths in reported road traffic accidents in 2013 involved at least one driver over the drink drive limit.2
The other fact is that nothing has changed in terms of the science of why alcohol has such a dramatic impact of one’s ability to drive. For reference, a blood alcohol concentration (BAC) of 0.04 percent is achieved by a 150-pound man consuming two drinks in 1 hour. It does not take much to cause impairment and one of the reasons why buzzed driving is starting to become a more prevalent education and awareness subject. Buzzed driving simply means your BAC is below the legal limit, but your driving ability may be impaired. Even a little impairment effects what we see, how we process what we see and the associated actions we take.
The brain's control of eye movements is highly vulnerable to alcohol. In driving, the eyes must focus briefly on important objects in the visual field and track them as they (and the vehicle) move. Low to moderate BAC's (0.03 to 0.05 percent) interferes with voluntary eye movements, impairing the eye's ability to rapidly track a moving target.
What you see translates to how you steer and your eye-to-hand reaction time. Significant impairment in steering ability may begin as low as approximately 0.035 percent BAC and rises as BAC increases.
Alcohol impairs nearly every aspect of information processing by the brain. Alcohol-impaired drivers require more time to read a street sign or to respond to a traffic signal than unimpaired drivers; consequently, they tend to look at fewer sources of information.
For example, drivers must maintain their vehicles in the proper lane and direction while monitoring the environment for vital safety information, such as other vehicles, traffic signals, and pedestrians. Alcohol greatly impairs our already limited ability to divide our attention between two tasks so we tend to favor one of them while moving. Therefore, alcohol-impaired drivers tend to concentrate on steering, becoming less vigilant with respect to safety information. It’s one of the reasons you can spot a driver under the influence swerving back and forth between driving lanes. Results of numerous studies indicate that divided attention deficits occur as low as 0.02 percent BAC.
Only you can make the responsible decision when it comes to drinking and driving.
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