Achieved by knocking over 250 traffic cones.
Most easily acquired by exiting out of the game, then opening it back up and going through the first (DMV) area repeatedly, knocking over the cones there.
Probably one of the worst upgrades; the ejected cones can kill pedestrians, but generally speaking it isn't worth using apart from getting the achievement for killing 12 pedestrians with the ejected cones. The Beary Music Box is much better for pedestrian killing purposes.