Cross-Examination on Horizontal Gaze Nystagmus in a Drunk Driving Case

Attorney - Sergeant, assume in a given case that you've got an angle of onset before 45 degrees.
Officer - Okay.

Attorney - What does that tell you?
Officer - The subject is probably under the influence of alcohol.

Attorney - Where does the 45 degrees figure come from?
Officer - I don't know.

Attorney - Please feel free to refer to the manual at any time, Sergeant, but aren't there two reasons?
Officer - That sounds familiar.

Attorney - Isn't the first reason that 45 degrees is close to the angle of onset for a person with a .10 percent blood-alcohol concentration?
Officer - Again, that sounds familiar.

Attorney - And what is the second reason for using the nystagmus field sobriety test to determine intoxication?
Officer - I don't recall.

Attorney - (Reading from manual) "...and because it is easy to estimate." Is that correct, Sergeant?
Officer - That's what it says.

Attorney - You mean, nystagmus is used to test for intoxication because it's only close—to how an average person's eyes will react?
Officer - Apparently.

Attorney - And because it's easy for the police?
Officer - Apparently.

Attorney - Sergeant, does the report indicate a third reason for using nystagmus?
Officer - A third reason?

Attorney - Does it say the test should be used because it's accurate?
Officer - Apparently not.

Attorney - Sergeant, do you consider nystagmus an accurate test of intoxication?
Officer - I think it's fairly accurate, yes.

Attorney - But the state of Kansas has not approved it as a blood-alcohol test,have they?
Officer - A blood-alcohol test? No.

Attorney - You've read an article concerning a study of the accuracy of nystagmus, reported in 25 Journal of the Forensic Society 476 (1985)?
Officer - I believe that's one of the things you mailed me.

Attorney - The study was conducted by a law enforcement agency—the Santa Clara County Criminalistics Laboratory, in California?
Officer - I believe so.

Attorney - They analyzed 129 actual cases where nystagmus was given—and compared them with actual BACs, right?
Officer - I believe so.

Attorney - What were the results of that study?
Officer - I believe there was some discrepancy.

Attorney - The officers consistently erred in estimating BAC, correct?
Officer - There was some error.

Attorney - What was the conclusion reached by these researchers, Sergeant?
Officer - They felt there were potential problems with nystagmus.

Attorney - In fact, didn't they conclude that nystagmus cannot be used to predict accurately the blood-alcohol level of a suspect?
Officer - Something like that, yes.

Attorney - You've read ''Psychophysical Tests for DUI Arrest'' by Tharp, a study commissioned by NHTSA?
Officer - Again, counselor, I believe you mailed it to me.

Attorney - Well, didn't that study conclude that some individuals with no alcohol in their systems demonstrated early onset of nystagmus?
Officer - I believe so.

Attorney - In other words, the nystagmus test showed perfectly sober people to be intoxicated?
Officer - Apparently it can happen in isolated instances.

Administration of Test
(Note: The officer demonstrate exactly how he administered the nystagmus test to the client in field.)

Attorney - In the demonstration you just gave, I notice that you didn't ask my client if he was wearing contact lenses?
Officer - It must have slipped my mind.

California DUI: A Drunk Driving Law Guide is intended to counter the political pressures of extremist groups seeking the passage of unfair laws, the erosion of constitutional rights and the eventual return of prohibition. The National Motorists Association sets forth its positions on controversial drunk driving issues, such as unconstitutional roadblocks, overemphasis on breath alcohol tests, unfair criminal penalties and the imposition of "automatic" license suspensions. See also "Responsibility in DUI Laws, Inc.", an organization dedicated to reforming harsh and misdirected DUI laws.

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