As of May 2018, it's federal law that all new cars and trucks in the U.S. must be equipped with  rearview monitoring technology. However, that still leaves millions and millions of vehicles produced before two years ago without rear-mounted sensors capable of telling you when you're about to back into a BMW while parking, for [&]

https://boingboing.net/2020/08/24/this-ingenious-parking-sensor.html