A set of headphones, similar to noise reduction varieties, but they instead reverse the doppler effect so cyclists can actually understand all those pithy sayings that are shouted at them by passing drivers.

They would also have to remove wind noise, and correct for the weird clipping/directional effects (other than doppler) that occur when something is shouted out a narrow opening that is passing you by at speed.
-- MechE, Feb 24 2011

Just put in a chip, triggered by a metal-detector, so that every time a car passes, it plays the single word "wanker" through the headphones. That would cover about 90% of the times people in cars have shouted out their window at me.
-- pocmloc, Feb 24 2011



random, halfbakery