At least in the US when I've used it, Apple's lane guidance is pretty comparable to Google's (i.e., mostly but not always on target).

I suspect "bad data" is both a little subjective and, as I mentioned in another comment, very location dependent. It's quite possible that one of the reasons Apple is starting to build their own location data set is because relying on other providers leads hasn't worked out so well for them outside the US. (Although I suspect they're going to still be dependent on those providers for years to come.)