DC DUI Sobriety Tests

A DUI arrest in Washington, DC can result in months or years of problems as you work to protect your legal records and to minimize the damage such a charge can wreak on your professional and personal life. If you have been cited or arrested for Driving Under the Influence (DUI) of alcohol or drugs in the District of Columbia, you must speak with a dedicated drunk driving attorney who understands this specific area of law and who can help protect your best interests. Arrests and convictions for driving under the influence can occur based on a number of factors, however most of these incidents include the accused being subjected to what is known as Standardized Field Sobriety Tests (SFST). To learn more about the SFST and your legal challenges and opportunities, please consider the information presented here. For a full understanding of your legal situation, however, you will need to speak with a DUI lawyer in Washington, DC who is familiar with DUI law and procedure in the region.

DC SFST and DUI Standards

The National Highway Traffic Safety Administration (NHTSA) conducted a number of studies to develop a battery of standardized tests to “obtain validated indicators of impairment and establish probable cause for arrest” (see NHTSA page on SFST). The Standardized Field Sobriety Tests are a battery of three tests that, used together by trained law enforcement, are claimed to have an accuracy rate of over 90 percent nationwide. They are comprised of the following three tests:

Horizontal Gaze Nystagmus (HGN)

When a person gazes to the side, there is an involuntary jerking of the eye that naturally occurs when a person’s eyes are rotated at high peripheral angles. This is called a Horizontal Gaze Nystagmus.

When a person is under the influence of alcohol, or has been impaired by alcohol, the nystagmus (involuntary jerking) happens at lesser angles and is more obvious. Furthermore, a person who has been drinking will likely have difficulty smoothly tracking a moving object (like a pen or a light) with his or her eyes.

An officer conducts the HGN test by asking a suspected impaired driver to follow a slowly moving object with his or her eyes. The officer moves the object, usually a small flashlight or pen, horizontally. As the officer does this, the officer observes the eyes of the suspected driver while looking for three indicators of impairment in each eye— six indicators in total. The indicators for each eye are:

  • Eye unable to smoothly follow the moving object.
  • Jerking of eye is distinct and sustained when the eye is at maximum deviation.
  • Onset of nystagmus (jerking of eye) at angle within 45 degrees of center.

If there are four or more indicators between the two eyes, then NHTSA research suggests the individual is likely to have a 0.08 Blood Alcohol Content (BAC) or higher. However, this test may also be indicating a medical issue in the suspect, rather than alcohol consumption. Nonetheless, exhibiting four or more indicators means the person is deemed to have “failed” the test.

Walk-and-Turn (WAT)

This is a “divided-attention” test, which means that a suspect has to divide their attention between mental exercises and physical exercises. For example, listening and following the officer’s instructions (a mental exercise) while engaged in simple physical activity (a physical exercise). People who have been impaired with alcohol may have trouble dividing their attention between mental and physical tasks in this way.

For the WAT test, an officer will ask the subject to take nine heel-to-toe steps along a straight line. Then, the officer will ask the suspect to turn on one foot, and return with nine heel-to-toe steps in the opposite direction. There are eight indicators of impairment the officer will seek to find in the suspect’s performance of this test:

  • Taking an incorrect number of steps
  • Being unable to stay balanced while listening to the instructions
  • Beginning before the instructions are finished
  • Stepping without touching heel to toe
  • Stepping off the line
  • Using one’s arms to balance
  • Improper turn (i.e., not turning on one foot)
  • Stopping while walking to regain balance

The research and studies by the NHTSA purports that 79 percent of people who demonstrate two or more indicators while being administered this test will have a 0.08 BAC or higher. Statistics aside, a law enforcement officer will likely be looking for two or more indicators, if a suspected drunk driver exhibits two or more indicators, the suspect is deemed to have “failed” the test.

One-Leg Stand (OLS)

The officer will instruct the suspect to stand on one foot, with the other foot around six inches (15 centimeters) off of the ground, while counting upwards out loud by “thousands” (e.g., one thousand-one, one thousands-two, etc.). The suspect will be instructed to do this until the officer instructs the suspect to put their foot back down onto the ground. The officer will then time the subject for 30 seconds, while observing the individual and looking for two or more of four indicators. The indicators are:

  • Using one’s arms to balance
  • Swaying while balancing
  • Hopping to maintain balance
  • Putting down one’s foot before instructed to do so

If an officer identifies two or more indicators, then the suspect is considered to have “failed” the test. This is because NHTSA research suggests that 83 percent of individuals exhibiting two or more indicators will likely have a 0.08 BAC or higher.


The tests are designed to be used together and, when administered properly, NHTSA research claims that officers report an accuracy rate of more than 90 percent in identifying impaired drivers with a BAC of 0.08 or higher. Failing only one test does not necessarily mean you will be deemed to have “failed” the SFST tests as a whole. And there are many other factors that could result in the failure to properly complete the tests, from obesity to improper testing conditions.

Contact a DC DUI Lawyer

Only a dedicated Washington, DC criminal defense attorney will be well-versed in all of these tests, and will be skilled enough to look for flaws or mistakes in the administration of the tests, which can result in the revocation of charges, or a dismissal of your case. The DUI attorneys at our firm have the necessary experience to handle your case, no matter how complicated. He will work to protect your rights and reputation throughout the legal process and beyond, including counseling you on the best methods for having such charges eliminated, or expunged, from your record.