There are three major studies that have evaluated many DUI field sobriety tests and determined that three qualify as Standardized Field Sobriety Tests. The Colorado Validation Study was conducted in 1995. The Florida Validation Study in 1997, and the San Diego Validation Study in 1998. The validation studies were conducted in conjunction with or sponsored by NHTSA. There are only three tests that became standardized field sobriety tests. They must be conducted in a standardized manner. In fact the manual itself states:
IT IS NECESSARY TO EMPHASIZE THIS VALIDATION APPLIES ONLY WHEN:
* THE TESTS ARE ADMINISTERED IN THE PRESCRIBED, STANDARDIZED MANNER
* THE STANDARDIZED CLUES ARE USED TO ASSESS THE SUSPECT’S PERFORMANCE
* THE STANDARDIZED CRITERIA ARE EMPLOYED TO INTERPRET THAT PERFORMANCE.
IF ANY ONE OF THE STANDARDIZED FIELD SOBRIETY TEST ELEMENTS IS CHANGED, THE VALIDITY IS COMPROMISED.
DWI Detection and Standardized Field Sobriety Testing Section VIII-3. 2000.
The standardized field sobriety tests are the Horizontal Gaze Nystagmus, One Leg Stand and the Walk and Turn. The Colorado Validation Study and the Florida Validation Study were conducted when the DUI legal limit was 0.10. The Colorado Validation Study found police officers made the correct arrest decision 93% of the time when they used the three standardized field sobriety tests. The Florida Validation Study found police officers made the correct arrest decision 95% of the time when they used those field sobriety tests.
The San Diego Validation Study was conducted because in 1998 many of the states were lowering the DUI legal limit from 0.10 to 0.08. This experiment answered the question, “Do the standardized field sobriety tests discriminate at breath alcohol content levels below a 0.10 level?” The San Diego Validation Study discovered police officers made correct arrest decisions 91% of the time when using the three standardized field sobriety tests for a DUI legal limit of 0.08.
Totality of the Circumstances
All of these tests assist a police officer in establishing probable cause to make an arrest for the crime of Driving Under the Influence. Police officers are not expected to prove beyond a reasonable doubt guilt of a crime before making an arrest. Putting that burden on a police office is unrealistic and beyond the scope of where they fit into the justice system.
However, these tests are quite subjective. Many people fail these tests even when they have not consumed one drop of alcohol. Anyone can establish a suspicion someone is under the influence by merely looking at them, but courts and juries require “scientific” evidence in this era of forensics shows like CSI and Forensic Files.