Here’s a frightening list: every month there has been a shooting of multiple people in the U.S. Of course not all are “mass shootings,” but many include the words “open fired” and were at places—like nightclubs, restaurants, NBA games, parties—with crowds: http://www.bradycampaign.org/xshare/pdf/major-shootings.pdf.
The Problem of the Too-Quiet Car
In spite of a government demand for automakers to fix the problem, there is still no consensus on how to warn pedestrians of noiseless vehicles.