The most critical evidence in a drunk driving case, after the blood or breath test, is the battery of field sobriety tests administered roadside by the officer before deciding whether to arrest. These ”tests” are designed in theory to determine any impairment which may affect the safe operation of a vehicle.
In fact, field sobriety tests (FSTs) simply test the physical skills and experience of the subject; a physically fit officer who has performed them hundreds of times will perform far better than an elderly, overweight, injured or unathletic person who is completely unfamiliar with the tests. Add to this that the suspect is nervous and/or scared, is attempting them in the dark late at night, in front of a police car with flashing lights, on a sloped roadside, with cars whizzing by within a few feet, possibly on high heels….Well, you get the picture.
As I’ve mentioned in past posts, these “tests” are unreliable and highly inaccurate (see Field Sobriety Tests: Designed for Failure? and Are Field Sobriety Tests Valid?). And this has been clearly demonstrated in scientific research.
In 1991, Dr. Spurgeon Cole of Clemson University conducted a study on the accuracy of FSTs. His staff videotaped individuals performing six common field sobriety tests, then showed the tapes to 14 police officers and asked them to decide whether the suspects had â€œhad too much to drink and driveâ€. Unknown to the officers, the blood-alcohol concentration of each of the 21 DUI subjects was .00% — stone sober. The results: the officers gave their opinion that 46% of these innocent people were too drunk to drive! In other words, the field sobriety tests were hardly more accurate at detecting intoxication than flipping a coin. Cole and Nowaczyk, â€œField Sobriety Tests: Are they Designed for Failure?â€, 79 Perceptual and Motor Skills Journal 99 (1994).
A common reply from police and prosecutors to these criticisms is that one of the FSTs is not affected by any of these considerations: horizontal gaze nystagmus (HGN). Basically, this test involves the officer observing and estimating measurements of a suspect’s eyeball movements. However, the test was never designed for detecting driving impairment nor for determining actual blood-alcohol levels, nor is the officer remotely qualified to administer this opthamological test — and certainly not under roadside conditions. (See my earlier posts, Nystagmus: the “Eye Test”, Nystagmus: The ‘Eye Test’ (part 2), Nystagmus: The ‘Eye Test’ (part 3), and DUI ‘Eye Test’ a Fraud?)
Years ago, when HGN was first introduced by police agencies around the country, the courts refused to admit the results into evidence — on the grounds there was no scientific accceptance of the test for determining alcohol impairment. Gradually, however, and with considerable political pressure from prosecutors and MADD, local courts gradually began admitting HGN into evidence. And the seemingly scientific nature of the test proved to be very impressive to juries.
Recenly, the Illinois Supreme Court considered whether HGN should continue to be admitted into evidence. Two days ago they filed their decision: No — not without a hearing where the prosecution must prove that the test is scientifically accepted. Illinois v. McKown (Docket No. 102373, filed September 20, 2007).
(Thanks to Illinois attorney Donald J. Ramsell.)