Reducing the BAC to 0.05 and implementing random breath testing has been very effective in reducing road deaths. We reduced the BAC limit to 0.05 in the 90's and this is why Australia has 5.7 deaths per 100,000 people (8 per 100,000 vehicles) and the US has 12.7 deaths per 100,000 people (15 per 100,000 vehicles). Because it sure as shit isn't because Australian's can drive.
For reference, Victoria introduced a 0.05 limit in 1966, NSW in 1980 and Qld in 1985. I'm not sure about the other states, but the only one I can imagine holding out until the '90s would have to be the NT.
It's interesting to hear older folks talk about drink driving in their youth, however. My father (now in his late 60s) worked in insurance and used to do a lot of driving in western Queensland. His habit after finishing his rural appointments was to buy a carton of beer and start the 2-3 hour drive home - he reckons most times he'd be 1/2 to 2/3 through it by the time he rolled into the driveway.
Of course, the roads were a lot emptier back then as well, which probably saved a lot of lives.