Driving Under the Influence, DUIs

Driving under the influence (DUI) and driving while intoxicated (DWI) are citations for an individual driving or operating a vehicle while impaired by alcohol or other substances. Driving a vehicle or operating machinery while under the influence of any mind altering substance is a crime punishable by law. DUIs are a serious issue in the United States and have been for decades. While the number of arrests is declining since the DUI laws have become stricter and more readily enforced, the issue of individuals driving while intoxicated is nowhere near being resolved.

The penalties for getting a DUI or DWI vary from state to state. Some states consider drunk driving to be a criminal activity while others consider it to simply be a traffic offense.  Either way you label it intoxicated driving is dangerous and should not be taken lightly.  Each state has its own penalties and many take into consideration other factors surrounding the incident before sentencing.  Other factors may include previous driving history, the situation in which the driver was cited (i.e. an accident, checkpoint, etc.), resulting physical injury, fatalities, etc.  Receiving a DWI can result in everything from a restricted or revoked license to community service or even jail time. Find out what the penalties are in your state.

How do they know?

Law enforcement officials have a series of tests that help them to identify if a person is intoxicated and should be charged as driving under the influence.  There are two main types of testing for intoxication, field sobriety test and chemical tests.

Standardized Field Sobriety Tests are performed to assess the driver’s physical and mental state. These tests often require that the individual in question exit the vehicle and perform a series of tasks used to test their coordination and mental acuity. The FST is composed of three components established by the US Department of Transportation. These three standardized tests established by the DOT are the Horizontal Gaze Nystagmus (HGN), Walk-and-Turn (WAT), and One-Leg Stand (OLS).

You may be wondering, what on earth is a Horizontal Gaze Nystagmus test?  First lets define nystagmus, ” Nystagmus is an involuntary jerking or bouncing of the eyeball that occurs when there is a disturbance of the vestibular (inner ear) system or the oculomotor control of the eye.” Basically it is an involuntary, jerky back-and-forth eye movement. To give you an example, if you think about spinning around in a chair and then rapidly stopping, your eyes will continue to move as if they are trying to keep up with the objects you were seeing while spinning, this is a form of nystagmus.

According to the NHTSA research “In the impaired driving context, alcohol consumption or consumption of certain other central nervous system depressants, inhalants or phencyclidine, hinders the ability of the brain to correctly control eye muscles, therefore causing the jerk or bounce associated with HGN.”  It was found in research sponsored by the National Highway Traffic Safety Administration that the Horizontal Gaze Nystagmus (HGN) was the most accurate way to assess whether or not a person was in fact intoxicated. Since a person can be a well trained intoxicated driver they may be able to pass the other field tests without any difficulty. However, the HNG test assesses a physiological effect of alcohol on the human body. This is an involuntary process that cannot be hidden or avoided no matter how skilled the driver. 

Additionally, you may be asked to perform other tests outside the defined standardized criteria of the SFST to demonstrate your cognitive abilities, such as reciting the alphabet backwards or accurately touching your nose with your index finger to test your fine motor coordination. All of the tests listed are ways for law enforcement personnel to determine your physical and mental state in order to make the best decision on your level of intoxication.  Being ticketed for driving under the influence or driving while impaired are serious offenses and should be taken as a serious warning for your safety as well as the safety of others.

Blood Alcohol Testing:

Besides physical field testing, officers rely heavily on measuring a person’s level of intoxication by measuring the percentage of blood in their body, this is known as blood alcohol concentration or content (BAC).  This measurement is typically based on weight but recent studies have found that BAC can also be affected by gender. In order to test an individual’s BAC without an expensive and skilled process like drawing blood a breathalyzer is used. This device, created in the 1950s by an Indiana State Police officer, Dr. Robert Borkenstein, is used specifically for the measurement of a person’s Blood Alcohol Content.

How does a breathalyzer work?

When alcohol is ingested part of the solution will evaporate out of the bloodstream through the lungs into the air. Alcohol is a volatile substance, meaning that it can readily be evaporated.  Alcohol is not digested when it is absorbed by the human body, nor is it altered chemically. Thus the volatile properties of the solution itself allow for evaporation into the air through any outlets from the bloodstream, i.e. the lung’s air exchange pathway. When the alcohol is evaporated through the lungs it is expelled upon exhalation. This is the content that may be tested by the breathalyzer. The body’s alcohol content is directly correlated to blood levels; each 2,100ml (milliliters) of alcohol is equal to 1ml of blood.  Thus, according to the properties of alcohol, a person’s BAC can be measured relatively easily.  The United States typically accepts a BAC of 0.08, this means that out of every 100ml of blood there is 0.08ml of alcohol. Historically, the standard was 0.10, and this is still accepted in some states, as each state has the right to set their own standard for drunkenness. However, each state that does not set their BAC limit to 0.08 is subject to federal withholding of funds for highway construction. Nevertheless, reimbursement will be provided if the state implements a 0.08 BAC limit within 4 years of receiving the penalty.