DUI Detection & Field Sobriety Tests

There are approximately a dozen exercises used by law enforcement as “field sobriety tests.” The most common are walk-and-turn, one-leg-stand, nystagmus (your eye follows the officer’s finger or pencil from one side to another), the “modified position of attention” test, touching finger-to-nose, reciting the alphabet, rapidly touching four fingers to the thumb, and the rapidly alternating hand pat. Contrary to popular belief, these tests are not legally required; you may decline to take them. If you take them, an experienced DUI lawyer can demonstrate to a jury that these field sobriety tests are “designed for failure.”

The federal government’s National Highway Traffic Safety Administration has funded research that found that only three tests – walk-and-turn, one-leg-stand, and nystagmus – effectively detect intoxication. According to these studies, all other field sobriety tests are unreliable and should not be used. Since the federal findings and recommendations, police agencies nationwide have been adopting the battery of three so-called “standardized field sobriety tests.” Most law enforcement agencies in California, however, have resisted the change: this permits them to (1) continue to use the tests they prefer, (2) avoid being held up to federal standards in the administration of the three tests, and (3) avoid the use of “objective scoring” (using a scoring system rather than just the officer’s subjective opinion).

Many California law enforcement agencies, including the California Highway Patrol, are increasingly using a small, handheld breath tester called a “Preliminary Alcohol Screening” (commonly referred to as “PAS”) device. A more recent permutation of the PAS device is the so-called “EPAS,” or “Evidential Portable Alcohol System,” which is basically a more sophisticated version of the PAS and intended to overcome legal objections to admissibility in evidence. These relatively primitive devices were designed as field sobriety tests to assist the officer in deciding whether there is probable cause to arrest and take the suspect to the station for more sophisticated breath or blood testing. 

Unfortunately, however, many California judges permit prosecutors to use the PAS results as evidence of blood alcohol concentration at trial – and in some cases, as the only blood alcohol evidence. It should be realized that, as with field sobriety tests, submitting to a field PAS test is not legally required — unless you are under 21 or already under arrest, and the PAS device is the only chemical test available.

The Law Offices Of Taylor & Taylor can help you better understand what is and is not admissible during a field sobriety test. Call (562) 330-4173 or fill out our online contact form today to get started.