Not a lot makes you feel stupider than backing into something. These kinds of collisions don't account for a lot of injuries or deaths, but they are costly. Backup cameras will be required on all new cars in the US starting in May 2018, but there is a lot more tech to help when you are in reverse. It basically fits in three categories.
Rear park sensors are very familiar, dating back about 15 years now. Using ultrasound or radar, they give you a beep that gets more urgent as you close in on something. Some GM cars vibrate your seat as a warning, but the idea is the same.
More recently, those rear sensors have crept around the sides of cars to warn about things approaching from the side you can't see when backing out of a driveway or crowded parking space. Depending on the situation they can be like eyes in the back of your head, or pretty much useless.
The rear cam was the big bang in backup collision tech, so ostensibly compelling that it will be required on all new cars as of May 1, 2018. Most offer simple distance lines, many offer dynamic trajectory prediction lines that show what you'll hit based on where you are currently steering, and some even overlay colors on the image to visualize priority of objects in your path.
In the last handful of years, cars have begun offering 360-degree surround views from a series of cameras around the car that add context to the backing task. Still, if you don't pay attention, they're useless, which begs our final category.
Drivers in cars with sensors and cameras still back into things, so the latest technology simply does their job for them. Reverse automatic braking is just like the forward automatic braking that carmakers will make virtually standard on new US cars by 2022. But today, rear automatic braking remains rare: The Insurance Institute for Highway Safety reports that only five percent of new 2018 cars offer it and less than one percent come with it standard. Still, it's probably where all new cars are headed.
All together now
The IIHS and the Highway Loss Data Institute (HLDI) say all these backup technologies combined seem to have reduced reported backing collisions by nearly 80 percent.
That seems to be a marked improvement from a few years ago when NHTSA data showed that as backup camera availability in new cars went up 112 percent between 2008 and 2011, backup accident injuries only went down eight percent.
Further penetration of all these technologies into the 240 million US cars -- and not just the 17 million new cars sold each year -- will make the biggest difference.