New crash testing of six popular 2017 vehicles shows that rearview cameras, parking sensors, and automatic rear braking can really save your behind when it comes to parking lot collisions.

The Insurance Institute for Highway Safety, or IIHS, performs much of the crash testing that makes the news, along with giving awards and ratings based on vehicle safety. This latest series of tests put rear crash prevention systems through their paces. Instead of measuring how the crash affects the occupants, this test rates the ability to avoid them altogether.

It's the first time that the institute has tested these features. "Some days we all could use help backing up, whether that's in a garage with pillars that obscure your view, in a crowded mall parking lot or on a busy downtown street," says David Zuby, IIHS executive vice president and chief research officer. "Collisions while backing up don't usually result in serious injury, but they still lead to some injuries and expensive repairs."

The testing puts the most weight on rear autobrake. That's when the vehicle automatically stops when it detects an impending impact while reversing. IIHS research says that it has the biggest impact on reducing impacts. The feature is a requirement to score a Superior rating on the test but is optional on just five percent (and standard on just one percent) of all 2018 model year vehicles.

The new rear crash prevention test assigns three ratings: Basic, Advanced, and Superior. To score a Superior, the rear autobrake system must be able to stop the vehicle from 6.5 km/h (4 mph) before hitting the target or reduce the vehicle speed to under 1.6 km/h (one mph). Vehicles that are only able to reduce speed, but not to under 1.6 km/h in all scenarios, score in the Advanced group, and vehicles that have only parking sensors and rear cross-traffic alert score Basic.

The six vehicles evaluated to launch the new tests were all 2017 models: the BMW 5 series, Cadillac XT5, Infiniti QX60, Jeep Cherokee, Subaru Outback, and Toyota Prius. All six were equipped with autobrake, cross-traffic alerts, and rear parking sensors.

The highest-scoring vehicles were the XT5 and Subaru Outback. They scored five out of six possible points, meaning that they had rear autobrake, parking sensors, and rear cross-traffic alert, and that they were able to reduce speed sufficiently or stop in every scenario. The 5 series, QX60, Cherokee, and Prius all rated Advanced, with two out of six points. That means that they had the features, but were not able to stop or reduce speed in every test scenario.

An IIHS study of GM vehicles showed that the trio of backup features reduced crashes while reversing that were reported to police by 78 percent. That suggests that they greatly reduced the number and severity of the backup crashes.

The IIHS said that rear cross-traffic alert is standard on just 11 percent of 2018 vehicles, with parking sensors on 33 percent. Rearview cameras become mandatory in Canada on new cars starting this May.