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

Attorney - In the NHTSA report, didn't it say that contacts can limit lateral eye movement, causing nystagmus?
Officer - That's correct.

Attorney - What type of template did you use in measuring the angle of onset?
Officer - I didn't use a template. No one in the highway patrol uses one.

Attorney - You did not use a template? Well, what kind of device did you use to measure the angle of onset?
Officer - None.

Attorney - None? You simply guessed what the angle was?
Officer - I didn't guess, counselor, I estimated. It was an estimate based upon extensive training and practice.

Attorney - You used protractors to check your accuracy during this training, didn't you?
Officer - Yes.

Attorney - But you didn't use one that night with my client?
Officer - As I said, I don't ever use one, nor does anyone else on the patrol.

Attorney - Sergeant, if we performed a little test right here in the courtroom, do you think you could detect the difference between 38 and 39 degrees?
Officer - I... maybe not.

Attorney - 42 and 44 degrees?
Officer - Maybe, I'm not sure.

Attorney - The accuracy of this test depends entirely on your ability to... estimate?
Officer - Of course.

Attorney - Well, when was the last time you had your accuracy checked?
Officer - Checked?

Attorney - Yes. How often do you get your ability to estimate angles checked for accuracy?
Officer - I'm not aware of any such procedure.

Attorney - Directing your attention to the NHTSA manual again, Sergeant...
Officer - Yes?

Attorney - Don't these federal reliability standards recommend monthly checks with a template to maintain accuracy in estimating the angle of onset?
Officer - I don't recall reading that.

Attorney - Would you like a moment to review the report?
Officer - No, I'm sure it's in there.

Attorney - Do you agree with the recommendation of monthly checks for accuracy?
Officer - I really don't think it's necessary.

Attorney - Are you saying you disagree with the national experts? Or are you saying that your accuracy doesn't need periodic checks?
Officer - I... just don't think it's necessary.

Attorney - You would agree that the accuracy of guessing the angle is critical to the validity of the test results?
Officer - Estimating, counselor, not guessing. And, yes, I would agree. The results depend on the estimate of the angle.

Attorney - As the computer people say, "Garbage in, garbage out," right?
Officer - Yes.

Attorney - Incidentally, Sergeant, do we have any evidence of the angle in this case?
Officer - Evidence?

Attorney - Yes. Besides your testimony: Do we have any corroboration of what the angle was?
Officer - Corroboration...

Attorney - Is there a videotape? Another witness?
Officer - No, of course not.

Attorney - I see. Then this nystagmus test depends entirely on your accuracy...
Officer - Yes.

Attorney - ...and, of course, on your honesty?
(The attorney has him demonstrate the test again.)

Attorney - I notice that you're holding the pen level with the eyes? And about six inches away?
Officer - That's contrary to the procedure recommended by NHTSA, isn't it? Officer - It's how I was trained.

Attorney - (Reading) "The first movement in each direction should be slow.... The second movement should be somewhat faster." Uh-huh.

Attorney - How many degrees per second do you move the pen during the test, Sergeant?
Officer - Degrees per second? I don't do it that way.