The primary student manual “DWI Detection and Standardized Field Sobriety Testing” published in February 2006 by NHTSA spends less than half a page on its subsection “Visual Detection of DWI Motorcyclists”. It’s in Chapter 5, Phase One “Vehicle in Motion” immediately after the section on visual cue descriptions for auto motorists.

However, in March of 2005 NHTSA published a brochure on the subject entitled “The Detection of DWI Motorcyclists”.

From both sources, the list of driving cues that officers are trained to look for in Motorcycle DWI/DUI cases are listed as either excellent (above 50% chance) or good (30-50% chance):

Excellent Cues

  • Drifting during turn or curve
  • Trouble with dismount
  • Trouble with balance at stop
  • Turning problems
  • Inattentive to surroundings
  • Inappropriate or unusual behavior
  • Weaving

Good Cues

  • Erratic movements while going straight
  • Operating without lights at night
  • Recklessness
  • Following too closely
  • Running stop light or sign
  • Evasion
  • Wrong way

Good fodder for DWI lawyers in motorcycle cases where the defendant is stopped ‘only’ for speeding (which is pretty common)…page 5 of the brochure:

Motorcyclists stopped for excessive speed are likely to be driving while intoxicated only about 10 percent of the time (i.e., 10 times out of 100 stops for speeding). But because motorcyclists tend to travel in excess of posted speed limits, speeding is associated with a large portion of all motorcycle DWI arrests.

In other words, while only a small proportion of speeding motorcyclists are likely to be considered DWI, the large number of motorcyclists who are speeding results in a large number of DWIs, despite the relatively small probability.

In cross examination, this can be used if the stopping officer testifies that speeding is a sign of intoxication (which belies the common sense of the jury as well).

Also, the officer should be crossed on all the things your client did right: no drifting, no trouble dismounting, etc.

DWI lawyers should consider asking the officer whether the dismount itself is a useful sobriety test. Many officers will openly scoff at the notion…that’s fine. Prod him to insist that only the NHTSA field sobriety tests are appropriate for evaluating the likeliness of intoxication or impairment.

Then have him read this paragraph from pp7-8 from the NHTSA brochure:

Trouble with Dismount

Parking and dismounting a motorcycle can be a useful field sobriety test. The motorcyclist must turn off the engine and locate and deploy the kickstand. The operator must then balance his or her weight on one foot while swinging the other foot to dismount. But first, the operator must decide upon a safe place to stop the bike. Problems with any step in this sequence can be evidence of alcohol impairment.

And having absolutely no trouble with the dismount is at least some evidence of a lack of impairment, correct Officer? (Doesn’t matter how he answers; the jury gets the point.)