Prosecutor Western Justice has an amusing – so amusing it’s possibly fake? – video up on his website from a DWI arrest. Basically, it’s the falling over type.

WJ introduces the video with this thought:

Defense attorneys always make a big deal that the walk and turn test is on an imaginary line! (gasp). Well,

The NHTSA DWI Detection and Standardized Field Sobriety Testing Manual has a chapter devoted to “DWI Detection Phase One: Vehicle in Motion”. A list of 24 driving cues which “police officers may use to detect nighttime impaired drivers” is the meat of the chapter.

These same 24 cues are also listed in NHTSA’s booklet “The

In Chapter 8 of NHTSA’s “DWI Detection and Standardized Field Sobriety Testing” Manual is a subsection entitled “Overview of Nystagmus”:

Nystagmus is defined as an involuntary jerking of the eyes. Alcohol and certain other drugs cause Horizontal Gaze Nystagmus.

Categories of Nystagmus

There are three general categories of nystagmus:

1. Vestibular Nystagmus is caused by movement

Vestibular Nystagmus is caused by movement or action to the vestibular system.

A. Types of vestibular nystagmus:

Rotational Nystagmus occurs when the person is spun around or rotated rapidly, causing the inner fluid in the ear to be disturbed. If it were possible to observe the eyes of a rotating person, they would be seen to

Nystagmus can result directly from neural activity:

Optokinetic Nystagmus occurs when the eyes fixate on an object that suddenly moves out of sight, or when the eyes watch sharply contrasting moving images. 

Examples of optokinetic nystagmus include watching strobe lights, or rapidly moving traffic in close proximity. The Horizontal Gaze Nystagmus test will not be influenced