The National Highway Traffic Safety Administration (NHTSA) has developed standardized procedures for the administration of the three field sobriety tests (FSTs) which NHTSA considers the most reliable. These standardized FSTs (SFSTs) are taught to and used by police officers across the country when investigating DUI cases. These FSTs are used in Michigan for investing Michigan drivers for suspicion that they are DUI.
The SFSTs are designed to be used by police officers to establish probable cause to arrest individuals who are under suspicion of driving while intoxicated and to support the administration of a breathalyzer test which measures more directly a person’s blood alcohol content (BAC). As direct, independent evidence of intoxication, however, SFSTs are extremely unreliable and have an immense margin of error. Furthermore, individual officers often administer the tests differently or under non-ideal testing circumstances, further reducing their reliability.
Here is a video of a non-standardized field sobriety test.
The NHTSA police officer training course separates the typical DUI investigation into three “phases”. These are (1) Vehicle in Motion, (2) Personal or Face-to-Face Contact, and; (3) Pre-Arrest Screening. The SFST’s are administered during phase three as part of the pre-arrest screening, and include only the Horizontal Gaze Nystagmus (HGN), the Walk-and-Turn (WAT), and the One-Leg Stand (OLS).
According to the NHTSA training manual, if the these tests are not administered according to the standardized protocol the results are “compromised.
If any other field tasks were administered in your case, or if these three tests were not given together, then the officer did not follow the NHTSA protocol. A failure to follow the NHTSA may provide a basis upon which to overturn your Michigan DUI arrest.