That's just right now. Changing the roads will take longer and be way more expensive than building enough AI that cars can self drive on existing roads safely.

That's just right now. Changing the roads will take longer and be way more expensive than building enough AI that cars can self drive on existing roads safely. Arguably, we're nearly there already. Several companies have self driving cars on some of the roads (not even counting Tesla here) and the scope of situations where these can operate safely is expanding. They aren't fixing any roads for this. This is all done in software. Five years is nothing for road construction. There's only so much that happens in such a short time span. However, it's a lot of time for making some software improvements.