Please allow me this opportunity to jump in and complain about the minority, but not insignificant number, of people that don't seem to be aware that that is even an option (just taking your foot off of the gas/accelerator to slowly decelerate).
Every couple weeks or so I seem to find myself behind someone that's always either accelerating, or braking, with the brake lights repeatedly flashing on momentarily for no apparent reason. It's like they realize that they're going just a little faster than they want, and definitely don't want to accelerate any more, so the only thing they know to do is hit the brake, instead of just taking their foot off of the accelerator. So they've hit the brake and now they're going too slow, so foot moves off the brake and back to the accelerator. Rinse, lather, repeat.
End rant. Thank you for this opportunity to vent.