Standardized Field Sobriety Tests (SFSTs) are used by police officers throughout New York as a means of establishing probable cause to make a DWI arrest. The three SFSTs are Horizontal Gaze Nystagmus (HGN), Walk and Turn, and One Leg Stand. Across New York , except in New York City which is a special case, SFSTs are administered roadside by police officers. In addition to aiding officers in establishing probable cause for an arrest, the SFSTs also are useful to the prosecution as evidence of intoxication at trial. A question which is often asked is does it even pay to agree to take these tests? In my view, the answer is no.
Drunk or not, it is rare to pass these tests. The officer will be able to find something the driver did wrong which he/she can deem a clue. For example, only two clues are required for a failure on the walk and turn test. Miss one heel to toe step out of 18 and start the test too soon and you have failed. For the HGN, whether the officer sees nystagmus is entirely subjective. I have attended multiple trainings on the HGN test and I am almost never sure if I have actually detected nystagmus. The plain fact is that the SFSTs are designed for failure, and the chance of passing one, let alone all three, is negligible.
If a driver is stopped, the odor of alcohol is detected, and the officer has asked the driver to get out of the car, an arrest is almost certain. It is better to not provide the government with the evidence of intoxication that will invariably result from taking the tests. Instead, politely refuse. While it is true that the prosecution will be able to use the refusal as evidence of guilt, this type of "consciousness of guilt" evidence is considered by courts to be weak and is not difficult to challenge.
As mentioned earlier, the city does things differently. In the five boroughs, the SFSTs are administered at the Intoxicated Driver's Testing Unit (IDTU), post-arrest. As the name makes clear, in the city, if you are asked to take SFSTs, after having already been arrested, you are presumed to be drunk.
For someone arrested in the city, there is even less reason to agree to take the SFSTs. These tests are being administered solely for the purpose of gathering evidence for the prosecution to present in court. Given the fact that all of the research which the federal government has conducted regarding the SFSTs contemplates that the tests will be administered in the field, the NYPD's approach is illogical. While the NYPD takes the position that they do it this way for officer safety, this approach only works for the NYPD because judges in the city frequently find sufficient probable cause to exist even without evidence from field sobriety tests. There is no reason for a driver who has already been arrested to agree to perform SFSTs. Since there is little upside to taking these tests, the best choice is to politely refuse.