Calling for Backup: IIHS Unveils New Rear Auto Brake Rating

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CARS.COM — The Insurance Institute for Highway Safety continues to raise the bar, making its crash tests tougher and requiring automakers to include more active safety equipment to receive high scores. Today, that bar goes even higher: IIHS is launching a rear-crash prevention ratings program to help consumers identify vehicles with systems that can prevent or mitigate low-speed backup crashes.

Related: IIHS Toughens Up Crash-Test Standards for 2018

The new rating system uses a three-tier formula: Models with optional or standard rear-crash prevention systems are rated superior, advanced or basic. That score is determined by performance in a series of car-to-car and car-to-pole tests with different approach angles, IIHS said.

Although the focus is on rear automatic braking systems, automakers also get points for parking-sensor-based systems that issue a warning beep or seat vibration when a vehicle is detected, and for rear cross-traffic alert systems that issue a similar warning when traffic is coming from the side of a reversing vehicle’s path. According to IIHS research of GM vehicles, the combination of a rearview camera, rear parking sensors and rear autobrake is reducing backup crashes reported to police by 78 percent.

For a superior rating, a vehicle’s rear autobrake system must avoid a crash or substantially reduce speed in a series of 4-mph tests. Systems are assigned points based on the number of runs that either avoid or barely hit the target, reducing speeds to less than 1 mph. For an advanced rating, a vehicle’s system must avoid a crash or reduce speeds in some of the tests. Vehicles that only have parking sensors and/or a rear cross-traffic alert system earn a basic rating.

In the agency’s first round of testing, it evaluated the rear autobrake systems of six model-year 2017 vehicles: the BMW 5 Series sedan, Cadillac XT5 SUV, Infiniti QX60 SUV, Jeep Cherokee SUV, Subaru Outback wagon and Toyota Prius hybrid hatchback. The Outback and XT5 earned a superior rating when equipped with optional rear autobrake systems, parking sensors and rear cross-traffic alert. The Cherokee, 5 Series, QX60 and Prius earned an advanced rating with the optional equipment.

Rear automatic braking systems aren’t common, and IIHS is hoping that changes in the future, though Russ Rader, IIHS’ senior vice president of communications, told that the backup auto braking system score won’t be factored into whether a vehicle earns the agency’s Top Safety Pick or Top Safety Pick Plus designations.

The system is standard on less than 1 percent of model-year 2018 vehicles and optional on only 5 percent, the agency estimates. Rear cross-traffic alert, however, is more popular; IIHS estimates the feature is standard on 11 percent of 2018 models and optional on 43 percent. Rear parking sensors are most prevalent, with estimates that the system is standard on 33 percent and optional on 59 percent of 2018 models.

“Let’s face it. 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. The systems we rate in our first batch of tests will help reduce the chances of a backing fender-bender,” David Zuby, the institute’s executive vice president and chief research officer, said in a statement.’s Editorial department is your source for automotive news and reviews. In line with’s long-standing ethics policy, editors and reviewers don’t accept gifts or free trips from automakers. The Editorial department is independent of’s advertising, sales and sponsored content departments.

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News Editor Jennifer Geiger joined the automotive industry in 2003, much to the delight of her Corvette-obsessed dad. Jennifer is an expert reviewer, certified car-seat technician and mom of three. She wears a lot of hats — many of them while driving a minivan. Email Jennifer Geiger

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