The ongoing saga of THE SILENT KILLERS continues to unfold. Today we encounter researchers at Stanford University demonstrating their external speaker system for the Toyota Prius, designed to warn the blind, children and other susceptible parties that an unusually silent vehicle is on the prowl.

Congress is currently evaluating a bill that would establish minimum sound levels for all vehicles and potentially make these two Stanford students very, very rich. Or at least the Chinese company that makes a knock-off version for a fifth the price. [NewScientist]