When it comes to frontal crash tests, the front-seat passenger in certain cars may not have the same protection as the driver, according to the Insurance Institute for Highway Safety, which says it has observed cars with structural reinforcements on the driver’s side lacking those reinforcements on the passenger side.
Related: Midsize SUVs Get Mixed Results in IIHS Crash Tests
IIHS frontal crash tests simulate hitting a barrier that overlaps 25 percent (small overlap frontal) or 40 percent (moderate overlap frontal) of the width of your car. The agency conducts the tests with the barrier hitting the driver’s side of the front the car, but not the passenger side.
Frontal crash tests from the National Highway Traffic Safety Administration affect the full width of the car, but they’re conducted at a slower speed (35 mph versus 40 mph) and allow a car to spread impact forces more evenly throughout its primary crumple zones. The IIHS small overlap test, by contrast, simulates when a car hits a tree or other narrow object by forcing the impact through the driver’s-side suspension, wheels and firewall. Those areas weren’t traditionally supported by a car’s main crash structure.
Automakers have responded to this IIHS test by widening the frontal crash zones, adding reinforcements to the outer edges of the passenger compartment and redeploying airbags to cover more space, or to deploy sooner.
Such actions help to reduce intrusion and signs of injury on IIHS crash-test dummies. But in some cases — “frequently enough,” IIHS spokesman Russ Rader said — automakers have made changes on the driver’s side only.
The cases are frequent enough to warrant further IIHS tests, Rader said.
The agency “saw that some vehicles have additional structures built into their front ends for crash protection, but only on the left [driver’s] side,” Rader said. “We saw it frequently enough that we decided to do some crash tests on vehicles that performed well in the driver-side small overlap test, and see what would happen if we moved the barrier to the passenger side.”
Cars.com reached out to every major automaker to see if they had made such driver’s-side-only fixes. Fiat Chrysler Automobiles released a statement that it “bases its vehicle designs on real-world [safety] performance, not third-party testing regimens.” Honda said it designs “both sides to reflect our target of protection (for both driver and passenger) for a small overlap crash,” spokesman Steve Kinkade wrote in an email. Kinkade said Honda’s body structures provide “the same level of protection on both the driver and passenger sides of the vehicle.”
GM, Nissan and Ford did not respond, and a Toyota spokeswoman declined to comment because such information “is proprietary.”
Results Matter Most
Even if the driver and passenger side have different crash structures, IIHS’ Rader cautioned that it isn’t “necessarily a telltale sign of a problem” because driver and passenger protection are fundamentally different.
“The passenger gets a bigger airbag, for example,” he said. “There is no steering wheel or pedals on the floor [in front of the passenger] that complicate driver protection.”
Hyundai spokesman Jonathan Wong had a similar sentiment. Hyundai works to “provide equivalent crash safety performance to both driver and passenger, but that may be done in designs that are not symmetrical,” Wong said. “We design vehicles to provide protection to all occupants in all of our vehicles. Design differences from right to left, or from light to heavy mass, will always be there, but the designs are intended to give equivalent performance in the real world.”
In at least one case, however, structural differences mattered. Rader said IIHS has taken two cars that scored well on the driver’s-side small overlap test and retested them on the passenger side for both the small and moderate overlap tests. On one car, IIHS engineers observed similar crash structures for both the driver and passenger sides. It passed the passenger-side tests.
But on the second car, engineers could see that “structural upgrades were obvious on the driver side but not on the passenger side,” Rader said. In a frontal test on the passenger side, that side performed worse than the driver’s side.
Rader would not share the make and model of the car or how much worse it did, because officials “don’t know yet how many more passenger-side tests we will need to do.”
The uneven approach to reinforcing crash structures likely arose after IIHS introduced the small overlap test in 2012. At the time, many cars fared poorly. But by 2014, a lot of them scored much better, and it wasn’t because of a glut of redesigns. Cars like the Buick Encore, Honda CR-V, Mazda CX-5, Toyota Camry and Toyota RAV4 improved their scores with structural changes in the same generation. Others, like the Chevrolet Equinox and GMC Terrain, went untested in the small overlap test until they received structural updates.
“We know that some automakers have needed to a take a short-term Band-Aid approach to upgrade for small overlap protection,” Rader said. “If an existing vehicle was designed before the small overlap test was implemented, and a full redesign is a ways off, the automaker may find it easier and faster to address the issue on the driver side first.”
That may seem like half a solution, but Rader said it’s better than nothing.
“We don’t want to discourage this kind of fix, because there is always a driver in a crash,” he said. “There isn’t always someone in the passenger seat. However, we do want the automakers to know that we expect both the driver and passenger side to offer the same level of crash protection with clean-sheet redesigns.”
IIHS’ collection of the latest federal data indicates that about 17 percent of all vehicle-occupant deaths in 2013 were front-seat passengers. But it’s hard to establish any fatality rate for this seating position because many accidents involve cars with only the driver.
Rader said that the IIHS is looking into whether to make its small overlap frontal test more like the agency’s roof-strength test, where IIHS randomly tests either the driver or passenger side of the roof. That ensures automakers reinforce both sides, not just the driver’s.
When will that happen? IIHS may not push any changes until the 2016 calendar year, or later.