78 kph/48 mph isn't that fast honestly, I think the biggest problem was that she was fucking wasted. If you can't keep your shit together at 50 miles an hour you probably shouldn't be driving.
The fact you're converting to mph makes me think you might not be familiar with speed laws in Australia and what the expected traffic speed is on the average street.
35m stopping distance is quoted for 50km/h. 78 km/h is 65m, or 10 car lengths. from the standard calculator, which assumes normal, non inebriated reactions. This bloke is cooked.
This is the problem; if we don't respect any speed over 10km/hr as being fast then it's easy for us to speed. Sure doesn't feel fast when you're driving, but 50km/hr can look pretty intimidating from the ground.
I recognize that, and maybe I'm just desensitized to it, but I live next to a road with a 30 mph speed limit and people blow by at 45 or 50 all day. Maybe the Australians are more desensitized to drunk driving than me, but I still think the bigger problem was her being wasted rather than speeding.