Helsinki records zero traffic deaths for full year

Don't let anyone tell you that better things aren't possible

Sure, but it's also paved with bad intentions, and neutral intentions. I would say that intentions have very little effect on the overall outcome of actions in general. Also good and bad are relative.

I would say that the road to outcomes are paved with actions. Not as pithy as the original though.

I think that means intentions alone are not enough.

* unnecessarily high speed limits

What are the downsides in this case?

Are you suggesting that facts are useful in public debate? Everyone has an agenda and they will follow it regardless of what you show them.

That's why nothing has ever changed in the history of humanity, because we're born with an agenda and never change it.