Law often eschews dividing "lines" though, in favor of fuzzy gray areas.

Somebody will inevitably reply that I'm wrong, and then I'll still travel slightly over the speed limit with no consequences for ~5 hours today.

It often does, and it also often avoids doing so. And there is a debate within the legal community about which approach is better.

See https://en.wikipedia.org/wiki/Bright-line_rule for a starting place to learn more about this.

Sure, but if you get pulled over while doing so the "Law" will be well within it's right to issue you a ticket despite your protestations of fuzzy gray areas. The law is quite clear here the fuzziness is purely in the discretion we grant enforcers of that law.

I wasn't drawing a distinction between the law as written and the law as enforced, because the latter is the one that matters in a practical sense. So sure, if you make that distinction, my comment doesn't make much sense.

The discretion police use is a huge gray area that is often problematic, but probably less problematic than not having a gray area.