Seems to me the cheapest solution is to glue old playing cards to the tire rims so that they smack something as the wheel turns. A variation of this worked on my bike when I was a kid. ...although I would still run into people occasionally ;-)
Bert, you're absolutely correct. And re-reading the NHTSA reduction estimate quote, they see the reduction over the life of the various models... which ends up being a very small number on a year-by-year basis.
Replay available now: A handful of emerging network technologies are competing to be the preferred wide-area connection for the Internet of Things. All claim lower costs and power use than cellular but none have wide deployment yet. Listen in as proponents of leading contenders make their case to be the metro or national IoT network of the future. Rick Merritt, EE Times Silicon Valley Bureau Chief, moderators this discussion. Join in and ask his guests questions.