The KSC reviewed the HGN test in some detail, including research on the HGN test's efficacy, and concluded that the government was required to show a credible correlation between the HGN test and a blood alcohol level:
One must show that any proffered evidence that is ostensibly based upon scientific principles does, in fact, have some credible correlation to the matter that must be proved. For instance, consider the hypothetical scenario of an officer who testified that the officer had undergone extensive training in the operation of a Ouija Board; that when a Ouija Board is asked if the driver being tested is DUI, the Board's arrow will point at "yes or "no"; that random sampling has shown that the Ouija Board correctly identifies when a driver's intoxication exceeds the legal limit 60% of the time; and that the Board's arrow pointed at "yes" when asked if Molitor was DUI. Should a court allow the officer to base reasonable suspicion upon the Ouija Board test results? Of course not. And at this point in the state of Kansas, the HGN test has no more credibility than a Ouija Board or a Magic 8 Ball.The KSC held that the city had failed to make this showing:
To be operating a vehicle under the influence of alcohol, pursuant to K.S.A. 2010 Supp. 8-1567(a)(1) or (2), the alcohol concentration in the person's blood or breath must have reached the level of .08 or more. If, as the above-referenced California study concluded, the HGN is essentially useless in predicting a person's blood alcohol level, then it is difficult to understand how that test can provide reasonable suspicion that a driver was driving under the influence of alcohol, as opposed to driving after two beers.The KSC majority also disagreed with the COA's holding that, even without the HGN results, the officer had reasonable suspicion:
Granted, the officer here testified that Molitor ran into or onto the curb while stopping his vehicle. Obviously, evidence of unsafe driving can suggest intoxication. But that alleged lapse of coordination must be viewed in conjunction with what followed. After stopping the vehicle, Molitor spoke without slurring his words, produced his identifying documents without difficulty, exited and proceeded from his vehicle without losing his balance, and, most importantly, passed the two admissible [field tests]. In other words, under the totality of circumstances, one could not reasonably suspect that Molitor's balance was impaired by alcohol to the point of being legally under the influence of alcohol.As a result, the Court reversed and remanded with directions to suppress.