About this work
What does the Crown actually have to prove?
It depends which paragraph is charged, and the two most common ones are proved in entirely different ways. Paragraph 320.14(1)(a) is operating a conveyance while the ability to operate it is impaired to any degree by alcohol or a drug. No reading is needed for that at all. It can be proved on the driving, the officer's observations, and the roadside conduct.
Paragraph 320.14(1)(b) is having, within two hours after ceasing to operate, a blood alcohol concentration at or above 80 milligrams of alcohol in 100 millilitres of blood. Impairment does not have to be shown at all. The reading is the offence.
That two hour framing is worth reading carefully, because it is not the same as the old law. The question is the concentration within two hours of ceasing to operate, not at the moment of driving. Section 320.15(1) then makes failing or refusing to comply with a demand its own offence, punished on the same scale.
A charge frequently includes more than one of these, and they do not stand or fall together. An answer to the reading is not an answer to the observations.