[mikhailfranco]

Note that linear markers on roads become incorrect when the road is diverted, re-routed or interrupted by new roads. For example, consider a new ring-road constructed to by-pass a town. However, US Interstates have special 3-digit numbering for ring-roads and other connectors.

Luckily for you, America is not building any new infrastructure, so mileposts should be stable for some time.

[paledot]

No new highways is lucky for all of us. Not maintaining the infrastructure you have is a problem, though.