4 mph speed-limits would be the norm (was Why gravity helps people work fas)

How fast was the Lunar Rover?

The answer is: faster than 4 MPH. It was in fact 8 MPH, and hit 11.2 MPH at one point. Designed and built in the 1960s.

I suspect that we can do even better with five decades between then and the early 2020s. And when the 2030s get here, oh wow.