Thursday, November 26, 2015
NHTSA post stop clues.PDF
AnacapaS ciencesIn, c.: AppendixE
DWI Detection at BACs Below 0.10
Eight post-stop cues wer€ recommended unchanged:
Cae29.2, Leaning on vehicle or object
Ctl,e 29.3, Fumbling with DL/registration (includes dropping, not realizing that they have it)
Cue 29.7, Repeating questions/comments
Cue29.l2,Odor of alcohol on breath/facial area/person
Cue 29.26, Slurred speech
Cue 29.33, Dfficulty exiting vehicle
Cue 29.37 , Slow to respond to fficer request/fficer has to repeqt request
Cae 29.40, Dfficulty with motor vehicle controls
In addition, Cues 29.1 nd 29.28 were combined to form the single cue Swaying, unsteady or
balance problems. And, Cues 29.13, 29.14, and,29.16 were combined to form the single cue Provides incorrect
information or claims to haveforgotten personal information, or changes story or qnswers.
None of the other post-stop cues was recommended forthe preliminary field study for a variety
of reasons. For example, the behaviors that relate to attitude provide conflicting guidance--as many
drivers are argumentative as are cooperative. tr'urther, a cheerful attitude should not be a cause for
suspicion of impairment; the implications of reasoning otherwise are chilling. AIso, cues that simply state
the obvious appear to be of little possible utility to officers (e.g., open container). In this regard, we
included the odor of alcohol from the driver (but not from a vehicle), not because it might be useful to
officers to know the obvious, but to provide the basis for including the cue in formal training, which then
will permit olficers to include the cue in their expert testimony.
Finally, some cues were eliminated because they might be indicators more of social class than of
alcohol impairment. For example, officers informed us that a flushed or red face might be an indication of
a high BAC in some people. However, the cue also is characteristic of agricultural, oil field, and other
outside work. Similarly, bloodshot eyes, while associated with alcohol consumptionn also is a trait of
many shift workers and people who must work more than one job, as well as those afllicted by allergies.
A disheveled appearance similarly is open to subjective interpretation. We attempted to limit the
recommendations to clear and objective post-stop behaviors.
BAC Distribution Number of Cases
-E - 10-