Auxtin

Do you just like people that have different variations of William in their name?

On desktop if you hover the mouse over the timestamp it gives you the specific date. Looks like your other post was submitted on March 26th, 2016.

arbitrary

based on random choice or personal whim, rather than any reason or system.

Is that wrong?

Except they're not. Speed limits were mandated to 55 mph because we discovered it's the best for gas mileage. This was not some arbitrary number, and it was something that was reached after well-informed debate.

Yes, some states have higher limits, but I really don't get the idea that there was no well-informed debate.

You look at the science, you try to figure out how to balance safety against convenience, you pick a value (a multiple of 5, almost invariably), and you run with it.

That's literally the opposite of arbitrary. If you have reasoning like this, it kind of implies that it's not arbitrary, in the most literal sense...