1992 NHTSA

No noticeable differences in Phase I or Phase II. Phase III HGN

The HGN test was fairly revised in this second edition.

It is rather oddly defined. “Nystagmus is the involuntary jerking of the eyes, occurring as the eyes gaze toward the side. Also, nystagmus is a natural, normalphenomenon. Alcohol doesn’t cause this phenomenon, it merely exaggerates or magnifies it[1].” So, on cross examination, just ask the officer if they are looking for something that is always there whether alcohol is present or not.

This manual also elaborates on PAN.

PAN I occurs when the alcohol concentration in the blood is greater than the inner ear fluid. PAN I occurs while BAC is increasing.

PAN II occurs when the alcohol concentration in the inner ear fluid is greater than in the blood stream. This occurs while BAC is decreasing[2].

Good luck asking the officer if the driver was in PAN I or PAN II.

The officer now must check for ability to track together and equal pupil size[3]. (Like the present version). The manual also now explains some different types of nystagmus[4]. If the driver has an artificial eye or obvious abnormal eye disorder, HGN is not recommended[5].

The first part was renamed to its present version Lack of Smooth Pursuit.

Distinct Nystagmus at maximum deviation was still not called sustained, but now the officer checks for “approximately 4 seconds[6].”

The officer also now looks for VerticalGaze Nystagmus (VGN). This is done in the same manner as the present version, except the officer did not need to hold the stimulus at all (unlike the present 4 seconds)[7].

Also, the officer now holds the stimulus slightly above eye level, like the present version[8].

Instead of concluding that 4 out of 6 clues will show someone is drunk or sober, now the officer can guess the driver is “impaired[9].” Again, the research relates to BAC, and not directly impairment, so NHTSA is still lying, but this time with different words.

The officer is informed that conditions that may interfere with a suspect’s performance of the nystagmus test include: one artificial eye, or very weak vision in one eye; wind, dust, etc. irritating suspects eyes; and numerous visual or other distractions impeding the test[10]. The language about one artificial eye, or very weak vision in one eye, is removed in future manuals. Walk And Turn

Instructions and scoring are the same as previous version, except the clue is now renamed: Improper turn[11].

Further, failure to complete test is no longer clue #9. The officer is now to “record failure to complete test as if the suspect failed each of the either validated clues. Cannot do the test is not a validated clue. Consideration should be given to terminating the test if the suspect cannot safely complete it[12].” Oddly, (unfairly) NHTSA did not give officers any guidelines as to when to mark a failure. For example, the previous instructions of steps off line 3 or more times, is in danger of falling, or otherwise demonstrates he or she cannot do the test.

In regard to validity, NHTSA removed the language stating it would be difficult for people with balance issues to do this test. Apparently, anyone with balance issues can now magically do a balance test without any problems. One Leg Stand

Directions: Apparently too many people did well, as the officer no longer tells people not to hop[13]. Further, if the suspect counts too quickly, the officer must have them keep counting[14]. Now, persons with injuries to the legs or inner ear disorders may have difficulty with the test[15]. (How nice of NHTSA to keep changing the guidelines without doing new research).


9.6.6 1995 DWI Detection and Standardized Field Sobriety Testing Student Manual[16]

No important noticeable changes in Phase I or Phase II. Phase III

NHTSA finally removed the language claiming a failure on the test is related to being drunk or impaired. HGN

The officer now checks both eyes during each part of the test before moving on to the next part. The manual also now adds that the officer should use the full 4 seconds while measuring for onset prior to 45 degrees. If the stimulus is moved too fast, the officer may go past the point of onset[17].  The officer is now instructed to face the suspect away from flashing lights, but an artificial eye, or one eye is no longer an issue[18]. VGN

The officer must now hold the stimulus for 4 seconds at maximum deviation[19]. Walk and Turn

The officer no longer marks people off for not walking straight on the line as part of heel to toe[20].In regard to the instruction stance, feet must actually break apart to be counted as a clue[21].

Test conditions: No more visible line, or high line. But “high” is now “hard.” Now the line must be “designated”[22].  But, if the conditions do not exist, the suspect should be asked to perform it elsewhere, or only HGN should be used[23].

NHTSA raised the difficulty due to age to 65 and removed any difficulty due to being 50 pounds overweight (it must be nice to be an authoritative government agency and just replace numbers with ones that are more favorable).

“Walk and Turn requires a high, dry, level, nonslippery surface with sufficient room for the suspect to complete nine heel-to-toe steps. A straight line must be clearly visible on the surface.

Improper turn is now defined as: “The suspect removes the front foot from the line while turning. Record this clue if both feet are removed from the line. Also record this clue if the suspect clearly has not followed directions as demonstrate.[24] One Leg Stand

Instructions and scoring are primarily the same. However, the officer now marks: cannot do test if suspect puts foot down three or more times, and to record as 4 clues[25].

Interpretation – Age for difficulty to do test raised to 65, just like the WAT.

[1]Id at VIII-11

[2]Id at VIII-11

[3]Id at VIII-14

[4]Id at VIII-11 – VIII-12

[5]Id at VIII-12

[6]Id at VIII-14

[7]Id at VIII-15

[8]Id at VIII-16

[9]Id at VIII-15

[10]Id at VIII-22

[11]Id at VIII-18

[12]Id at VIII-18

[13]Id at VIII-20

[14]Id at VIII-21


[16] Hereafter referred to as NHTSA 1995

[17]Id at VIII-16

[18]Id at VIII-26

[19]Id at VIII-18

[20]Id at VIII-20

[21]Id at VIII-20

[22]Id at VIII-20


[24]Id at VIII-20

[25]Id at VIII - 24