If my maths is correct, altho' at 50, he is only doing 66.6% faster than the speed limit, the force of any collision impact is 178% greater. In the event of a collision, the chances of, say, a pedestrian surviving the impact is close to zero

I'm basing this on dimly remembered formula of F = M * (V sqared), where f = force, M = Mass and V = speed. If I've misremembered it, I fully expect to be corrected very shortly.

By the way, on the subject of speed limits, the city of Hull, in East Yorkshire, England, introduced 118 * 20mph areas and saw fatality rates fall by 90%. Could have something to do with the above formula, but also because, at that speed, most people will survive a collision.

No doubt all you have to do is suggest introducing such a policy in US cities and they will automatically fall in with the logic