Earning a Top Safety Score From IIHS Just Got Much Harder – Here’s Why

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One safety group continues to make top ratings harder. This time it is side-impact testing.

Back in the bad old days of auto safety, the only thing between a driver’s left ear and the bumper of a pickup truck about to hit the drive rin a side impact was a pane of glass. And it wasn’t even Tesla shatterproof glass. the Institute For Highway Safety (IIHS) developed a way to test vehicles consistently for side-impact safety back in 2003. The first years the test were conducted only about 20% of the vehicles earned a Good rating. To their credit, automakers responded – big time. Today, 99% of the vehicles that IIHS has tested earn the IIHS’ Good rating, enabling them to qualify for the Top Safety Pick Award. A 2011 study of a decade of crash data found that the driver of a vehicle rated Good by IIHS is 70 percent less likely to die in a left-side crash than a driver of a vehicle rated poor. So, the crash ratings and real-world crash studies correlate well.

Now that every car has decent side-impact protection, IIHS wants to up the ante. The group has done this in a number of ways over the past decade, consistently challenging automakers to improve safety, rather than become complacent. “This is an opportunity to build on what we’ve learned in more than 15 years of side testing,” says IIHS Senior Research Engineer Becky Mueller. “We’ll update the things that need updating, but we don’t need to throw out the things that still work well.”

The IIHS test involves a small female dummy in a vehicle being hit from the side by a movable barrier that simulates a pickup truck of full-sized SUV hitting it smack in the driver’s door and window. Automakers have strengthened the “B-pillar” between the doors in a sedan, and they also added fast-acting side-impact torso and head/neck airbags. These airbags are the fastest to deploy in a car, since they have so little time to be effective.

The crash energy or force of a vehicle hitting another is represented by the formula F=1/2 MV². As you can see, the best way to add energy to the crash test would be to just make the side-impacting sled go faster. And IIHS has done exactly that, increasing the sled speed from 31 MPH to 37 MPH. Because they are engineers and don’t like half measures, IIHS is also making the sled heavier. The new sled weighs 4,200 pounds, which is what a Ford F-150 actually weighs. The last change being considered is to change the barrier that hits the vehicle. Currently, it is a honeycomb structure that was developed to mimic the front of a turck or SUV. However, these types of vehicles still use the older (and deadlier) body-on-frame constructed that the Model T was built on. Cars and crossover all use more advanced unit-body construction without these frame rails. The frame rails have a tendency to localize the energy and possibly punch-through a car. Also, in tests comparing the sled to a real truck or SUV, IIHS noticed the crash movement is a bit different. So IIHS is looking at ways to better mimic that real-world effect they have observed.

The scientists at IIHS will make this test harder in every possible way and have endeavored to make it as realistic as they can without sacrificing a $50K truck as the impacting vehicle. We’d like to tip our hat to the folks at IIHS. We look forward to seeing which manufacturers will most quickly improve the safety of their vehicles in response to this new standard for automotive safety.