Most people, especially p-platers, forget that p-platers are still learner drivers. I don't mean that in an offensive way, but I know a fair few and having been driving for 6 years longer than them I notice how quick they are to abandon simple, safe rules. Like usually drive at 10 and 2, or at least when maneuvering the car; and braking harder earlier, rather than cutting it close when emergency braking.
I've taken a few L-platers I've had to teach to a quiet, un-used abandoned street and told them to slam on the brakes, there's nothing more important than having some sense of how quick your car will stop, and knowing what abs does and how it helps.
Plenty of drivers fail at even that.
It's not just that, it's that the road is not a race track. It has kids running out and drivers falling asleep. The road a surprisingly dangerous place.