A similar method is in indeed used in many jurisdictions: https://en.wikipedia.org/wiki/Speed_limit#Operating_speed https://en.wikipedia.org/wiki/Speed_limit#O

A similar method is in indeed used in many jurisdictions: https://en.wikipedia.org/wiki/Speed_limit#Operating_speed https://en.wikipedia.org/wiki/Speed_limit#Operating_speed There are advantages and disadvantages as with everything.