Have you ever really thought about it? Say you travel at 10-15 MPH over the speed limit? On a typical trip of 10 miles on a 45 MPH street, theoretically you will save between 2 1/2 and 3 1/2 minutes. And because many traffic signal along highways are preset for vehicles to travel at or below the speed limit, you will probably find yourself stopping at more lights and thus your actual gain would be reduced or even eliminated. Thus, speeding for short distances on a non-controlled access highway does not really save you any time.
Check out this chart we prepared for you: