IIHS Praises Automatic Rear Braking While Condemning Partially Automated Driving

The Insurance Institute for Highway Safety (IIHS) just praised seven out of eight crossovers it tested with rear automatic braking. This comes as the group has pivoted its focus toward pedestrian safety. However, the Insurance Institute for Highway Safety and the Highway Loss Data Institute (IIHS-HLDI) also published a paper expressing safety concerns over automated driving systems. The takeaway from that piece was that alleged self-driving systems added nothing in terms of safety, but that partially automated safety systems (like automatic braking) were a net positive.

Considering these automated driving systems have things like automatic braking embedded within them, the take is somewhat confusing.

The crossover tests were released on July 18th and promptly shared by Automotive News. Vehicles were tested from a variety of angles with the goal of not making contact with the target while reversing.

From Automotive News:

The Ford Escape, Honda CR-V, Mitsubishi Outlander and Subaru Forester all earned the highest rating "superior." Mazda CX-5, Toyota RAV4 and Volkswagen Taos received an advanced rating and the Hyundai Tucson earned a basic score.

The results come as front automatic emergency braking systems become more common in vehicles as automakers prepare for the systems to become mandatory in 2029. However, rear automatic braking is much less common, standard in only 23 percent of vehicles from the 2023 model year.

However, the IIHS-HLDI had published a paper a week earlier claiming that automated driving systems offered no tangible safety benefits. The opinion was based on examining the crash data of 2017–2019 Nissan Rogues and 2013–2017 BMW vehicles, cross referencing the installed features. But the resulting assertions feel largely speculative and do not include data pertaining to vehicles that used no advanced driving aids, as they’ve effectively been eliminated by the industry. In fact, the data used in the study doesn’t even stipulate what systems were active (or not) during the time of the relevant crash.

“Everything we’re seeing tells us that partial automation is a convenience feature like power windows or heated seats rather than a safety technology,” IIHS President David Harkey stated.

From the IIHS-HLDI:

Jessica Cicchino, senior vice president for research at IIHS, tried to determine if such safety benefits might be hiding in the HLDI data. She compared police-reported crash rates for the same BMW and Nissan vehicles that HLDI studied in 17 U.S. states during 2013-22. Although she also had no way of knowing whether the features were switched on at the time of the crash, she was able to restrict her study to the front-to-rear and lane departure crashes that partial automation could potentially prevent. She looked at crashes on limited-access interstates, freeways and expressways and then looked separately at crashes on other roads.

Like HLDI, she found substantial reductions in crash rates associated with crash avoidance features.

Front-to-rear crash rates were 49 [percent] lower for Rogues with forward collision warning and AEB and 54 [percent] lower for Rogues with forward collision warning, [automatic emergency braking] and [adaptive cruise control] than for vehicles with no crash avoidance features. There was no significant effect on lane departure crash rates from lane departure prevention.

Unlike HLDI, Cicchino found larger reductions associated with partial automation. Front-to-rear crash rates were 62 [percent] lower for Rogues with ProPILOT Assist than for vehicles without any crash avoidance systems. Lane departure crash rates were 44 [percent] lower for Rogues with ProPILOT Assist and lane departure prevention than for unequipped vehicles.

Property damage liability claims were also 8 percent lower on Nissan’s equipped with automatic braking and the group speculated that adaptive cruise control might reduce accident rates because it tends to default toward longer (and therefore safer) following distances. Forward collision warning systems were also supposed to have resulted in minor improvement in liability claims. But these systems are rarely sold individually and tend to come as a series of comprehensive bundles that package numerous features together.

Surprisingly, despite modern vehicles beaming data about your vehicle back to the factory every millisecond you’re driving, the industry doesn’t provide concrete numbers about how these systems perform. That leaves the IIHS to draw a lot of conclusions based on aggregate data.

It’s the author’s assumption that some of the reasoning behind the claims comes down to finances. Insurance companies (which fund IIHS research) would presumably rather keep the onus of any wreck on the driver and automated driving systems blur the line of who is at fault. However, they’re effectively reliant on the same crash-avoidance systems that the IIHS is so eager to praise. The same sensors are in play, as is the hardware that allows the vehicle to intervene.

“With no clear evidence that partial automation is preventing crashes, users and regulators alike should not confuse it for a safety feature,” stated Cicchino. “At a minimum, safeguards like those IIHS promotes through its rating program are essential to reduce the risks that drivers will zone out or engage in other distracting activities while partial automation is switched on.”

Meanwhile, we’ve published numerous articles on how these same systems are a double-edged sword. While something like automatic emergency braking can indeed save an inattentive driver from having an accident, they’re also prone toward dulling the senses of a driver — perhaps raising their likelihood of making a mistake to begin with.

This is not to suggest that the IIHS is totally off the mark, or even wrong, however. While the group failed to point out that lane keeping, adaptive cruise control, and other advanced driving systems are prone toward keeping drivers distracted, it did notice that there were some blind spots in its reporting — one of the biggest being the inability to delineate when these systems are being used.

Automated driving systems tend to come into play while cruising on the interstate at higher speeds. Conversely, things like automatic emergency braking have proven largely ineffective at higher speeds and typically come into play below 35 mph. This has been shown in numerous rounds of testing, including those conducted by the IIHS. Vehicles equipped with partially autonomous systems will also invariably come equipped with things like automatic braking and collision warning systems, making it harder to separate the data into two distinct categories and forcing researchers into making assumptions.

It also needs to be reiterated that fatal accident rates in the United States saw a generalized increase as these systems became commonplace in vehicles. While there are several other factors at play, most notably the increased size of modern SUVs/pickups and the implementation of touch screens, we did not see much of a change as cell phones became popular. That would seem to suggest that advanced driving aids are either not as successful as claimed or that they're simply not enough to offset other factors that have driven up severe automotive accidents.

[Image: IIHS-HLDI]

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