Just like any other car on the road today, electric cars have to undergo increasingly difficult crash tests at the hands of official testing bodies like the National Highway Traffic Safety Administration (NHTSA) and the Insurance Institute for Highway Safety (IIHS) to prove that they have the safety acumen needed to keep occupants and other road users safe.
Unveiled in 2012, the latest test procedure from the IIHS — known as the small overlap frontal crash test — is the most brutal yet. And while Chevrolet’s 2014 Volt range extended electric car has what it takes to pass the new crash test with adequate scoring, its rival, the 2014 Nissan LEAF, scored poorly.
The IIHS small overlap frontal crash test mimics a crash scenario which is becoming more common on today’s ever-congested roads. As the name suggests, it simulates a 40 mph frontal collision in which just 25 percent of the car’s bumper makes contact with a rigid object.
Instead of the partial overlap test, where the impact occurs over half of the car’s bumper, the small overlap frontal crash focuses all of the impact forces on just a quarter of the car’s bumper, causing far more damage than if the same forces were spread over a larger area. Worse still, impacts of this type often miss the main frontal crumple zone, meaning impact forces are more readily transferred to the car’s cabin and its occupants.
With heavy battery packs on board and thus more inertia than many other cars in their segment, it’s harder for electric cars to pass the small overlap front test with high marks than it is for similarly sized, lighter gasoline cars.
As the video above shows, the Chevrolet Volt managed to adequately protect its occupants from harm during small overlap frontal crash testing, receiving good ratings for occupant injury protection, and adequate ratings for its restraints and kinematics and structure. As a consequence, the IIHS awarded the Chevrolet Volt an ‘Acceptable’ rating in the tough test, translating to an overall safety rating in other IIHS crash tests good enough to give it a 2014 IIHS Top Safety Pick + rating, the highest safety award offered by the organisation.
Like the Chevrolet Volt, the 2014 model year Nissan LEAF was awarded top ratings in the moderate overlap front, side, head restraint and roof-strength tests. But when it came to the small overlap front test, things were dramatically different.
During the force of the simulated impact, the IIHS says the Nissan LEAF suffered major intrusion into the cabin, with up to 16 inches of intrusion in the lower occupant compartment and 14 inches in the upper compartment.
In addition, the steering column, instrument panel and parking brake pedal were all pushed back towards the driver, dramatically increasing the risk of injuries to the driver’s left knee, lower leg and possibly left thigh. This resulted in the all-electric hatchback receiving a ‘Poor’ rating from the IIHS in this particular test but an overall ‘Good’ rating for its model year.
It’s worth noting at this point that in its small car tests, the IIHS noted that very few cars fared well in the small overlap frontal test, with only the 2014 Mini Cooper Countryman managing the top ‘Good’ rating. The Fiat 500L, Nissan Juke and Mazda 5 all received the lowest rating, with the Mazda 5 being the only car tested by the IIHS fro the 2014 model year small cars to fail to achieve an ‘acceptable’ rating in the side impact test.
Despite the LEAF’s poor performance however, the IIHS praised both the LEAF and the Chevy Volt for retaining battery pack cohesion during testing, with neither car showing signs of battery pack damage after the suite of exhaustive safety tests.
To read both crash test reports in full, you can do so by heading to the IIHS website.
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