"Well, actually, no, officer, I wasn't speeding. You see, while you clocked me at 90mph [c] between toll booths [atoms], once you factor in time at the booth, you'll see that I am actually driving much more slowly."

But equating decrease in velocity with "slowing down" would be confusing for most laypeople, at least.

Nobody would say that they slowed down if they increased their speed as they went through a turn.