by Marcelline Burns, Ph.D.

Although significant gains in traffic safety have been achieved over the last decades, it can be predicted with certainty that thousands of individuals will be the victims of alcohol-involved crashes in 1999 and, unfortunately, probably for many more years to come. Whenever we venture into the driving environment, as driver, passenger, cyclist, or pedestrian, we place ourselves at risk of becoming a victim. No matter how skilled and prudent we may be, there is no guarantee that we will be able to protect ourselves (or those we care about) from alcohol-impaired drivers. Since this amounts to an equal-opportunity potential for injury and death, one might expect all responsible adults to wholeheartedly support efforts to deter DUI drivers through sound programs. Unfortunately, such is not the case. Witness the persistent and vigorous efforts to prevent use of Horizontal Gaze Nystagmus (HGN) as a roadside sobriety test. To the extent those efforts succeed, traffic officers will have been denied a valid and reliable tool. That will not be a small loss since police officers are a vital link in the chain of events that removes impaired drivers from the roadway. If they are not allowed to use HGN and perform their duties with maximum effectiveness, we all will be more at risk than need be.

This HGN resource guide is a "good news" document, not only for the judges, prosecutors and law enforcement officers to whom it is addressed, but for all safety-minded citizens. The guide brings together a scientific and pragmatic approach to understanding HGN. Not only does it present sound information, it also provides a road map for the effective use of that information. Perhaps it will short-circuit the inaccurate and self-serving view of HGN that is propounded by defense counsel. Just possibly, the false arguments will subside, and traffic court time can be devoted to meritorious issues.

Lest the foregoing seem too harsh an indictment of the HGN challenges (and the challengers), consider the following. First, a very simple fact is often overlooked, perhaps because its simplicity belies its significance. The simple fact is that within a short time a traffic officer must warn, cite, arrest, or release every motorist who is stopped. Making no decision is not an option, nor is deferring the decision to a later time. The officer must make the often difficult decision, basing it on observations of driving, the driver's general behavior, appearance, and statements, and performance of roadside tests. The goal is (or ought to be) the release of non-impaired drivers and the arrest of DUI drivers. Given that goal, common sense dictates the use of roadside tests that have been shown in scientific studies to be the "best." Common sense also asks, "If not these best tests, then what?" It is telling in the extreme that the challengers to HGN offer no alternatives. Their argument is not, "Use Test X , which is a better test, instead of HGN." It is simply, "Do not use HGN."

Secondly and importantly, HGN was selected and recommended as one test within a battery, and officers are trained to use it in that context. It is a sensitive and accurate index of alcohol impairment, but for a skilled traffic officer, it is only one of multiple sources of information. Yet, arguments against it proceed as though it were the only evidence available to the arresting officer. It is true that circumstances occasionally prevent the administration of psychophysical tests, but even then HGN is not the only evidence. The consumption of alcohol may also be revealed from a suspect's demeanor and speech, as well as the odor of alcohol on the suspect's breath. Other factors include the time and place at which the suspect is stopped. (What are the odds of alcohol involvement when a violation is by an elderly parishioner leaving Sunday morning services vs. a young adult in the vicinity of a bar at 0200?). It approaches absurdity to suggest that officers will be able to check suspects' eyes but unable to make any other observations.

Finally, consider validity. If a test measures what it purports to measure, it is a valid test. The claim that HGN occurs in the presence of alcohol or other depressants, inhalants, and phencyclidine and is reliably associated with impairment by those substances has been validated repeatedly by breath, blood, and urine tests. In fact, except for individuals who refuse to provide a specimen, an officer's observation of HGN is routinely subjected to validation. The question which begs to be answered then is, "Why would officers confidently rely on HGN if their observations were not validated?" It is difficult to imagine that they would continue to use a test which repeatedly leads to decision errors.

HGN is not a magic bullet, but it is an excellent tool of investigation. It will be a boon for traffic safety and good fortune for all who use the roadways if police officers are trained and encouraged to use it at roadside. I am hopeful....... no, I am confident, that this resource guide, seriously studied and considered, will serve that objective.