So how do these work? Are they regular checkpoints you run into where you get swabbed or something? Sounds highly invasive and frankly not something any nation should put up with.
They tried at times to do that shit in the US, we responded by protesting and in some cases folks would post up down the road with signs warning people. They don’t try them anymore.
-GC
In Vic (and elsewhere) they set up booze buses, which are basically what they sound like, a bus where they do booze and drug tests. They block the carriageway and RBT people (not everyone is tested, to avoid queues, but everyone passes the cops through the same lane) driving through selectively. If you fail the roadside (count to ten to detect alcohol and sometimes a drug wipe which takes a few mins to indicate), they stick you on the evidential machine, which is pass or fail. If you pass alcohol, you're ok, if you pass drugs then they'll send the sample away for lab analysis and you could still be summoned to court at a later date (but you can drive off and keep your licence at that time).
If you fail either roadside, immediate 24h licence suspension (for drugs) or ticket for drink driving and suspension for x duration (depending on low/med/high range). 0.05-0.08 used to just be a fine in Victoria, but since 2018(?) it's a minimum 3(? I think) month loss of licence.
Just the rules here, you agree to them by holding a licence I guess. In the UK they can't breathalyse you unless they suspect you're under the influence, but they can stop vehicles for any reason. Here they can test you for impairment for any reason. Also in the UK, even if you fail massively, you can only get your licence disqualified by a court, so you can drive away from the cop shop as soon as they release you - they advise you not to for a fair while, and people have been breatho'd leaving the station and subsequently charged a second time (as they're once again DUI), but you can still legally drive until a court bans you, whereas in Aus the cops can suspend your licence roadside.
Going off topic now, but it's the same with speeding - do 150km/h on a freeway here, and you're looking at a suspension (although if it's only 25-30km/h over it usually commences in 28 days, but they can immediately suspend for "excessive speeding" which is something like >45km/h over the limit). Do 200mph in the UK, you'll get a summons to court but can drive away from the scene and continue driving for a while - there's even a chance (not at 200mph, you're probably going to jail at that speed, but say 100mph, or 30mph over the limit (70mph on dual carriageways/Motorways), which is usually a ban) that you'll be fined and receive points for exceptional circumstances, which can include needing to drive to do your job (not commuting) - no such leniency here...