It’s long been a favorite trick of DUI lawyers to help their clients accused of drunk driving: pick apart the dashcam footage of the field sobriety test given by the officer. If the attorney can prove that there was some extinuating circumstance that led to their clients failing the test, then they just might have a shot at getting them off without a penalty.

Pixabay What’s hard to dispute, however, is the ability of the test to assess the telltale physiological signs that betray a person’s sobriety or lack thereof. So, how, exactly, does it do that? First, a little history… In 1975, the US National Highway Traffic Safety Administration wanted to come up with a way for police officers in the field to be able to assess the sobriety of a suspected drunk driver. What they came up with was a battery of three tests that could determine if a suspect had a Blood Alcohol Content (BAC) of greater than .10%.

Flickr As laws in certain states became more strict and the legal level of intoxication was lowered to .08%, more research was done to insure their veracity. Here are the three parts of the field sobriety test that a suspected drunk drivers must go through. If they pass, they’ll be allowed to continue on their way, but failing means that they’ll be looking for a good dui attorney and spending thousands of dollars in fines, court costs, increased insurance premiums, and other expenses. The three tests that make up the full field sobriety test are the Horizontal Gaze Nystagmus Test (HGN), Walk & Turn Test (WAT), and the One Leg Stand Test (OLS)

Flickr Horizontal Gaze Nystagmus Test (HGN) According to the American Optometric Association, nystagmus is “a vision condition in which the eyes make repetitive, uncontrolled movements. These movements often result in reduced vision and depth perception and can affect balance and coordination. These involuntary eye movements can occur from side to side, up and down, or in a circular pattern.” In this test, the police are looking for the jerkiness of the eyes as the suspected drunk driver gazes toward the side. There are three clues in each eye for a total of 6 clues. The specific clues they’re checking for are “lack of smooth pursuit of the eyes, distinct and sustained nystagmus at the eyes’ maximum deviation and nystagmus starting before the eyes reach 45 degrees.” [Wikipedia]

Flickr While they originally calculated a person showing all six clues to have a BAC above .08%, but they’ve calibrated it so that now showing 4 - 6 clues puts the suspect at a greater than .06% BAC. Walk & Turn Test (WAT) In the second test, the suspect must take nine heel-to-toe steps along a straight line while keeping their arms at their side and counting eachs step out loud. What the officer is looking for here is the suspect’s ability to follow instructions, maintain balance without stopping, and walk the correct number of steps in a heel to toe fashion. One Leg Stand Test (OLS) In this final test, the suspect is required to stand on one leg for 30 seconds. Its purpose is to measure balance and coordination while dividing the suspect’s attention and measuring their ability to follow directions.

Flickr Here, the officer is looking for swaying, hopping, using the arms to maintain balance, or putting the foot down. Taken as a whole, the tests in the field sobriety test paint a pretty good picture of a person’s sobriety and how much of a danger they are to other people on the road. To say that our efforts to curb drunk driving in this country have worked would be an understatement, but we still need to stay vigilant. From Responsibility.org: Since 1982, drunk driving fatalities on our nation’s roadways have decreased 51%, while total traffic fatalities have declined nearly 20%. Among persons under 21, drunk driving fatalities have decreased 80%. Despite this progress, we still have more work to do, and our commitment to eliminate drunk driving is stronger than ever.

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Free Stock Photos Hardcore drunk drivers continue to wreak havoc on our nation’s road accounting for 70% of drunk driving fatalities, where there is a known alcohol-test result for the driver – a trend that has remained relatively unchanged for more than a decade. It makes sense for our roadways, and it makes sense for the individual who chooses to drink to plan for some other form of transportation such as a taxi, public transportation, or Uber to get home. The cost alone of getting convicted of drunk driving should be enough to scare most people off. When the combined cost of increased premiums, missed time at work, court costs, and the fees of a good drunk driving (DUI) attorney are added up, they can come to well over $10,000. Continued testing continues to be done on the effectiveness of the field sobriety test in determining intoxication levels, and each new experiment confirms its effectiveness proving that the best way to beat the test is to not drink and drive in the first place.