And here is a test

Starting today, a zero blood alcohol limit applies to drivers aged 20 and under.

We'd expect this to show up in the drinking stats as a drop in drinking among folks in that cohort.

Any change in the crime rate (not counting drink driving) for 16-20 year olds relative to 21-25 year olds, and relative to the prior relationship between the two, and barring other anti youth crime initiatives coming on-stream, could then be used as part of an estimate of the elasticity of crime with respect to alcohol use among youths. Get the percent change in alcohol consumption among the cohort and the percent change in crime committed by folks in that cohort.

Give it a couple years...