[svandamme]

I would think for the most part roads by now have been designed so it's blatantly obvious that you're going down an exit way in the wrong direction.

At this time you either have to be blind drunk, sky high, senile or suicidal to go the wrong way.
At least it is here in Belgium.. And yes it does happen, but if you ask me how to fix it, I would say, put more cops on the roads to patrol and get bad drivers OFF the road before they do harm.

And it's not that difficult to spot them.. just drive around and you see em everywhere.
swerving from lack of attention (phone) or lack of ability (old age) or lack of sobriety, or lack of driving skill (bought or foreign or cheated drivers license)..

But at least here in Belgium you have a bigger chance of winning the lottery then finding a cop on the road doing patrol (instead of finding cop on his way to some kind of intervention/meeting/whatever)
I know, because I'll admit since moving back to Belgium my driving has gotten worse , speeding etc , the chance of getting caught is next to nothing if you keep your wits about. In Holland driving was better because you'de see the cops pull folks over regulary.. that keeps you honest.