A driver records a breath result well below the per se limit, yet the officer notes weaving, slurred speech and poor divided attention. What is the likely outcome?

Why D is correct

Most jurisdictions provide two distinct routes to proving impairment, and the number is only one of them. The per se route is administrative: reach the stated concentration and the offence is made out. The second is evidential: establish that the driver's ability was genuinely impaired and a lesser tier of impaired-driving offence may still be available at any reading. That distinction explains why someone well under the figure can be arrested on the strength of driving pattern, speech, odour, eye observations and field sobriety performance. A lower number reduces exposure; it immunises nobody.

Why the other options are wrong

A. No case, because the reading came in under the legal limit

Coming in under the stated figure defeats the per se route alone. The separate question of whether this individual was actually impaired remains live and independently provable.

B. Only a warning, since the number is what matters

A low reading does not reduce everything to an officer's discretion either. Documented weaving, slurred answers and failed divided-attention tests are evidence of impairment in themselves, and what may be charged rests on what was observed rather than on what the machine printed out.

C. Automatic dismissal once any medical condition is mentioned

Mentioning a medical condition introduces an explanation to be assessed, not a defence that disposes of anything. Conditions can mimic impairment and can also genuinely cause it.

On the road

A driver is comfortably under the number but cannot walk a line or follow a moving finger. The case does not require a high reading; what was observed is itself the case. That is precisely why two tiers of impaired-driving offence exist in most systems — one for the number, one for the behaviour — and the second does not need the first in order to succeed.

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