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Sobriety Tests

How do the police know how much alcohol you have in your bloodstream? There are several different types of tests that can be used to determine if you are likely to be intoxicated and/or the amount of alcohol in your bloodstream. Immediately after you are pulled over on suspicion of drunk driving, the officer will administer field sobriety tests to help determine whether or not you are intoxicated. Field sobriety tests consist of a series of actions designed to test your reflexes, balance, coordination and cognitive function. The officer is free to use whatever series of tests he or she chooses, but there are three tests in particular that are recommended by the National Highway Traffic Safety Association: the horizontal gaze nystagmus, the walk and turn, and the one-leg stand.

For the horizontal gaze nystagmus, the officer will have you follow the horizontal movement of a pen, his flashlight or his finger as he slowly moves it across your field of vision. In this test, police officers are trained to look for jerking or twitching of the eyeball, which may indicate alcohol consumption and intoxication. According to the National Highway Traffic Safety Association, this test is about 77% accurate.

In the walk-and-turn test, the officer requires the suspect to walk 9 steps in straight line, turn on one foot, and come back. Falling, using your arms for balance and not staying on the line can indicate that you are drunk. This test is around 68% accurate in determining if your BAC is above the legal limit. In the one leg stand, you must stand on one leg for 30 seconds. The officer will suspect that you have been drinking if you put your foot down early, use your arms for balance, hop for balance, or fall. The one leg stand is about 65% accurate.

Other common field sobriety tests include reciting the alphabet backwards, touching your nose with your arms closed, and counting backwards. Failing any of these could be considered probable cause for a DWI arrest and an actual chemical test.

There are three types of chemical tests that the police can use to get a BAC reading from you: a breath test, a blood test and a urine test. Breath tests are the most common, followed by blood tests. You do not get to choose the type of test you take. However, New York is unique in that you do have the right to consult an attorney to decide if you should take a chemical test or not. Refusing a chemical test has its own penalties (see the section below on implied consent). An attorney can help you decide what’s best for you. However, you don’t have the right to actually see an attorney in person, and you are only allowed to consult one over the phone if it won’t impede the arrest process.

The breath test, the most commonly used type of chemical test, estimates the amount of alcohol in your blood by measuring the amount of alcohol in your breath and performing some calculations to estimate your BAC. The first breath test machine was invented by Rolla Harger in 1938. Professor Harger referred to his contraption as the “Drunkometer.” Today, breath test machines come in all shapes and sizes, from small and portable to large and stationary. If you are pulled over for drunk driving, you may be given a breath test at the scene, in jail, or both. Breath tests readings can come back incorrect if you have been exposed to other chemicals that have a similar chemistry to alcohol, such as some cleaning products. Blood tests are thought to be more accurate but they aren’t used as often. 

Recently, personal breath tests have been introduced to the consumer market. If you purchase one of these devices, you can test your breath yourself before you get behind the wheel of a car. Can these products save you from getting a New York DWI charge? Possibly, but it’s not guaranteed. Personal breath tests are not as accurate as the breath tests used by law enforcement officers. Remember, the machine only has to give a reading that’s .01 too low to get you in trouble if you rely on it to tell you whether or not it’s safe for you to drive. So, it’s best not to rely on personal sobriety tests. Instead, if you’ve been drinking, forgo driving altogether until your body has had time to remove the alcohol from your bloodstream.

 

Law enforcement tip-offs of DWI

What can cause a police officer to suspect you of DWI? Obviously, if you toss an empty beer can out of your car window, that’s a tip-off (plus you can get cited for littering). However, there are other behaviors that police officers look for, including:

  • Weaving
  • Driving in the middle of the road or on the wrong side of the road
  • Going too fast or two slow.
  • Stopping for no apparent reason or using the wrong turn signal.
  • Braking suddenly or erratically
  • Narrowly missing hitting another vehicle or object.


If the police see you doing any of the above, you can expect to see some flashing lights in your rearview mirror. However, police departments in New York also hold DWI checkpoints, where they stop everyone to see if they might be driving while intoxicated. At a checkpoint, police are looking for suspicious behavior such as excessive nervousness and for the smell of alcohol. If you see a checkpoint up ahead, don’t try to turn around and take another route. There is usually another officer watching for people who try to evade a checkpoint.

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