Standardized Field Sobriety Testing


If a DC police officer pulls someone over and suspects that the driver has been drinking, the officer will usually ask the person to step outside the vehicle and perform the standardized field sobriety tests (or “SFSTs”). The SFSTs are made up of three tests. Officers who administer the test have usually been certified by the National Highway Traffic Safety Administration (or “NHTSA”) to perform such tests. Their certification typically consists of a 40-hour training course and a test at the end of the course, which requires them to administer the SFST’s exactly consistent with NHTSA standards. All the attorneys at Scrofano Law PC have undergone this training and received the same certification as the officers.

The three tests consist of the Horizontal Gaze Nystagmus Test (or “HGN”), the walk and turn, and the one leg stand. With each test during the DC DUI investigation, the officer looks for specific cues of impairment to determine whether the person passes or fails to test. Ultimately, if the officer perceives enough “cues” of impairment, he or she will make a DUI arrest.

The Horizontal Gave Nystagmus Test

The HGN is the test that involves the officers asking a DUI suspect to follow his pen or other stimulus with the suspect’s eyes. Many people mistakenly think the officer checks to determine whether the suspect moves her head while following the pen. In reality, the officer looks for specific types of nystagmus in each eye. Nystagmus is an involuntary jerking of the eyes that is extremely subtle.

The first thing the officer is trained to detect is whether the eyes show a lack of smooth pursuit, which is basically where the eyes move from side to side in a choppy manner (like a broken windshield). The second cue is distinct and sustained nystagmus at maximum deviation. The officer here will leave the stimulus at for about four seconds on each side to see if the eyes jerk in a “distinct and sustained” manner. Finally, the officer checks for “onset of nystagmus prior to 45 degrees.” This final cue is where the officer takes shorter passes on each side to a forty-five-degree angle to see if nystagmus (or the involuntary jerking of the eye) occurs. The officer is trained to detect these three cues in each eye for a total of six cues.

A typical DUI arrest will occur when the officer observes either four out of six or six out of six cues on the HGN (although some officers may make an arrest after only supposedly observing two of six). Many problems can occur in the officer’s observation and interpretation when administering the HGN test. For example, the lighting on the side of the road late at night (frequently where the test occurs) may not be enough to see these very subtle eye movements. In addition, if the officer does not perform the tests exactly according to NHTSA’s standards, the results from the test are compromised. Moreover, you cannot see what your eyes are while the officer does the test and typically no independent source confirms the officer’s observations. There are also many things other than alcohol intoxication that cause nystagmus, including, among other things, caffeine, nicotine, and certain health issues.

The Walk and Turn Test

The walk and turn test (or “WAT”) requires that the suspect walk nine steps heel to toe along a straight line, pivot three steps to turn, and then walk nine steps back heel to toe. Police officers that NHTSA has certified to administer SFST’s look for eight cues of impairment during this test. Like with the HGN test, the officers do not tell the suspect what the cues are and they are the sole judge of whether they pass or fail the test.

There are eight possible cues in the WAT. The main point of this test is to determine whether the suspect can listen to instructions and follow them. Supposedly, the ability (or inability) to perform this test is evidence of alcohol impairment.

In DC DUI and DWI investigations, officers are not trained to look for or interpret an individual’s nervous behavior as a possible cause for the inability to perform this test satisfactorily. Often times, as well, police officers fail to give the instructions properly but, because no independent mechanism exists to verify the accuracy of the testing, it does not matter, and they will make the arrest anyway. Things have improved slightly in this arena since the police have started wearing body worn camera and defense lawyers can now watch how the officers administer the test.

Officers are trained to find an actual line on the ground (like a line on the sidewalk) when they administer the test in a DC DUI traffic stop. However, they often just ask the suspect to use an “imaginary” line. The type of shoes you have on can impact the suspect’s ability to perform the test. Knee injuries, obesity, and whether the ground is at an incline can all negatively impact your ability to perform the test. Police officers who administer this test are supposed to ask if the suspect has any health problems that could impact their ability to perform the test. However, most people, whether they have health problems or injuries, simply don’t know what type of injuries would impact their ability to do this test.

The One Leg Stand Test

The final test in the SFSTs is the One Leg Stand Test. During the One Leg Stand Test, the police officer will instruct the person suspected of driving under the influence to hold one leg six inches above the ground and count aloud. The officer will instruct the person to count in the thousands (i.e. “one thousand one, one thousand two, etc.”). The counting will go for thirty seconds but the officer will not inform the person how long to count in advance. Like with the HGN and Walk and Turn, the officer looks for specific cues of impairment. For the One Leg Stand Test, the four cues are:

  • If the suspect sways while balancing.
  • If the suspect uses their arms to balance.
  • If the suspect hops to maintain balance.
  • If the suspect put your foot down.

This task can prove difficult for a completely sober person. Especially doing the test late at night on the side of the road with at least two police officers surrounding them, police lights flashing, cars speeding by, and with the knowledge that failure to successfully complete this test could land the person in jail.

Prosecutors in DC aggressively enforce DUI laws. Accordingly, its very important that if you find yourself arrested for a DUI in DC, you immediately consult with an aggressive DUI lawyer who will fight to protect your rights. Contact Scrofano Law for a consultation today.