They can already use this. What do they do with the information? If they have a passive detection device that says there's alcohol somewhere, what do they do then? When would they use this? If they haven't witnessed overt bad driving or erratic driving, and it there's no smell of alcohol on the breath or in the car, why would they use this device? What would give them the notion that they should use it?
On October 18th, 2016. See this statement in context.