[andor]

That's a rather distasteful argument to make and reminds me of Covid deniers blaming underlying medical conditions for deaths.

Kinetic energy is m*v^2, so yes 20% makes quite a difference.

Also, what's the point of a speed limit of x if 1.2x (or x+19) is tolerated. There is no good reason for a margin.

[choeger]

Oh, come on. First of all, speed limits are chosen conservative for various conditions. Second, cars are usually better than expected. And finally, every rule has margins (see my examples above). There is no reason to consider speed limits special.