H
hard rain
Random breath testing was introduced in Australia in 1982. Its very common here and not just on fri - sat nights. They will set up on a stretch of road and flag you down. YOu can refuse to be tested but the punishment for this is the equivalent of highest range of alcohol impairment and you will loose your license and get a criminal record. Statistically every licensed driver is tested around every 2 years and for many this is there only contact with police.
I would just like to add that we also have random drug testing in Australia. It is much less common than DUI testing, but they can do a saliva test from cannabis, methamphetamine and MDMA. They don't test for opiates as these are to commonly used in prescribed pain killers.
They often set up tests near large festivals (notably the Nimbin Mardi Grass).