Driving Cues
Interim Report, Visual Detection of DWI, 1979
NHTSA · 1979 · 5.4 MB
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Published in 1979, Interim Report, Visual Detection of DWI, 1979 is a NHTSA's research report in the government's underlying science library. It documents the visual driving cues officers are trained to associate with impairment — and their real probabilities. Because it is the government's own source material, it sets the standard a DUI case can be measured against — not a standard the defense invented.
What this document establishes
It sets out the visual driving cues officers are trained to associate with impairment — and their real probabilities. As primary-source material, it lets you compare what actually happened in a case against the written standard, rather than relying on how the procedure is described in court.
How it's used in a DUI defense
The driving-cue guides list the behaviors officers are trained to associate with impairment, along with their own stated probabilities. A single minor cue is not proof of impairment — and the guide's own numbers say so. That distinction between a probabilistic cue and actual impairment is where the reasonable-suspicion and weight arguments live.
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