If you're driving 45 in a 40, that may sound like 12% faster, but once you add traffic, lights, stop signs, turns, etc - you'll find that the 12% all but evaporates. Even if you're really pushing it and going 15 over, at most speeds and for most typical commutes, it saves very little.
Most of the time speeding ends up saving on the order of seconds on ~30 minutes or shorter trips.
Just about the only time it can be noticeable is if you're really pushing it (going to get pulled over speeds) on a nearly empty highway for a commute of 1.5+ hours.
If you're driving 45 in a 40, that may sound like 12% faster, but once you add traffic, lights, stop signs, turns, etc - you'll find that the 12% all but evaporates. Even if you're really pushing it and going 15 over, at most speeds and for most typical commutes, it saves very little.
Most of the time speeding ends up saving on the order of seconds on ~30 minutes or shorter trips.
Just about the only time it can be noticeable is if you're really pushing it (going to get pulled over speeds) on a nearly empty highway for a commute of 1.5+ hours.