Flying Lawyer,
No, I'm not confusing two different offences, I am pointing out that the law is confused (and in part) undefined and wrong.
The law specifically identifies impairment of function (Sect 92).
It then quotes absolute levels in breathe, blood and urine making it an offence so to do.
However, urine testing does not demonstrate impairment. Period.
Having alcohol in your urine has no relation whatsoever with your ability to do a function (in the same way that wearing bad ties does not impair your function - just reflects bad taste).
This is so, for simple biological reasons, i.e. urine is not reabsorbed into the body.
In relation to traffic offences, blood/alcohol is generally relied upon, although there are certified breathe test machines too.
Urine is not (these days) used - a blood sample is required.
As I have pointed out, it is possible to be clear on breathe and blood but positive on urine. That makes a fool of the law.
Whether for Sect 92 or Sect 93 Urine testing should not be used.
And the law should be changed, before any damage is done.
This is just bad (and, of course, presently untried) law.
One only has to ask what is meant by "drugs" and what limits apply for each "drug"? If zero tolerance is applied, then this law could get very ugly in application or simply be ignored in practice.
The law in relation to "drugs" is completely undefined.
That IS bad law.