California DUI

Horizontal Gaze Nystagmus

Attorney - Well, we don't know, do we? Because you did not check. What was the amplitude of nystagmus at the maximum lateral deviation?
Officer - The what?

Attorney - The degree of eye jerking at the furthest movement of the eye, Sergeant.
Officer - Maximum deviation, yes, there was distinctive jerking at the maximum deviation.

Attorney - But what was the amplitude?
Officer - I didn't really notice.

Attorney - Did you consider "smooth pursuit" as a factor in the nystagmus test?
Officer - I did.

Attorney - And did you consider this an accurate indication of intoxication?
Officer - I did.

Attorney - As accurate as onset?
Officer - Yes.

Attorney - You place a lot of weight on it?
Officer - I suppose so, yes.

Attorney - Then, again, you disagree with NHTSA? (Reading) "Smooth pursuit eye movement... is the least reliable of the three signs."
Officer - My understanding was that all three were equally reliable.

Attorney - Sergeant, what was my client's score on your nystagmus test?
Officer - Score?

Attorney - Yes, what was his total score on the test?
Officer - There's no score, counselor. You either pass or fail. He failed.

Attorney - (Feigning surprise) Then your test is entirely subjective?
Officer - It is based upon my observations.

Attorney - YOU decide whether he passed or failed?
Officer - Of course.

Attorney - Why do you choose not to use an impartial, objective scoring system?
Officer - You can't score a nystagmus test, counselor. Either the jerking indicates intoxication or it doesn't.

Attorney - Are you aware that NHTSA recommends an objective scoring system?
Officer - I am not.

(Attorney has the officer review the report.)

Attorney - Have you now reviewed NHTSA's scoring sheet?
Officer - I have.

Attorney - Apparently, using the objective system, four of six possible points indicates failure, right?
Officer - Apparently.

Attorney - Do you still think it's not possible to use an objective method for deciding whether a person passes or fails the test?
Officer - I suppose it's possible, but it's not how we were trained.

Attorney - Sergeant, you've read the NHTSA law enforcement booklet, Guide for Detecting Drunk Drivers at Night?
Officer - I think that was in the stuff you mailed me.

Attorney - Isn't it true that NHTSA studies indicate that even if nystagmus is administered exactly as recommended, the test has only a 77 per cent reliability factor?
Officer - That's what it says.

Attorney - So, even if the test is done as recommended, you will be right only three out of four times?
Officer - Apparently.

Attorney - Even if you gave the test as recommended, one-fourth of those who "fail" will be... innocent?
Officer - Apparently.

Attorney - And you admit that you did not give the test as recommended?
Officer - I gave it the way I was taught.

The Science and the Law
A resource guide for judges, prosecutors and law enforcement that deals with Horizontal Gaze Nystagmus.

DUI Arrest FAQs
The 20 questions most frequently asked by those arrested for DUI, from a California lawyer.

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California DUI