Alcohol—At Any Level May Impair Drivers

Alcohol impairs drivingWhile there is a ‘legal limit’ that dictates how much alcohol people are allowed to drink before getting behind the wheel, a recent University of California, San Diego study suggests that alcohol consumption at any level may impair drivers.

How was the study set up?

David Phillips, a UC San Diego sociologist, and colleagues found that when it comes to those people who are to ‘blame’ for fatal car crashes, it is oftentimes the “minimally buzzed” drivers rather than those who had nothing to drink.

The study consisted of 570,731 fatal collisions between 1994 and 2011. The study opted to use the FARS (official U.S. Fatality Analysis Reporting System) database because it reports on the blood alcohol content (BAC) of the driver in 0.01 percent increments. In order to complete the study, researchers divided the accidents into two distinct groups. These included:

  • The “minimally buzzed” group (with a BAC of 0.01 percent)
  • The “buzzed” group (with a BAC of 0.01 to 0.07 percent)

The results of the study

The researchers found that those drivers with a BAC of 0.01 percent (far below 0.08 – the legal US limit), are 46 percent more likely to be at fault than the sober drivers that they collided with in their accidents. After combing through the studies, the researchers found that there is no sudden shift where a driver goes from blameless to ‘at fault’ when it came to driving while below the legal limit.

Not the sole factor in motor vehicle collisions

While the public at large and law enforcement officials may believe that a 0.08 BAC is a meaningful boundary that somehow puts people at risk, this is clearly not the case. Instead, Phillips recommended that the law should focus on what official accident investigators see rather than to assume that a certain BAC level is problematic.

The researchers calculated ‘blame’ by observing more than 50 different driving factors that are coded into the FARS database. These include instantly recognizable factors such as driving on the wrong side of the road and driving through a red light.

Many of the analyses use a ‘natural experiment’, a collision between a driver who had consumed alcohol and someone who was sober. The researchers argue that because both parties collide at exactly the same time and in the same circumstances, it instantly standardizes many potentially confounding variables. Those variables might have included roadway conditions and the weather conditions at the time of the accident.

What this means for people who consume alcohol and getting behind the wheel

According to Phillips, the findings are unmistakable – there is no safe combination when it comes to consuming alcohol and driving a vehicle. The data of the study supports the earlier ‘Buzzed driving is drunk driving‘ campaign from the National Highway Traffic Safety Administration. Phillips stated that while there are federal agencies that are advocating for lowering the legal limit to below 0.08 percent, their study appears to be the first study to research how people drive at these lowered levels.

The importance of being safe

Just because it is legal does not mean that driving after having consumed a few drinks is not a great idea. Because someone is not in violation because of their BAC does not mean that they might not end up harming themselves or others if they decide to drive after having consumed alcohol.