The IIHS (insurance institute for Highway Safety) just released the results of its crash test of sub-compact cars. One of the IIHS’s new tests is actually more difficult than the government crash tests for cars to pass. That new test is the small overlap front crash test, designed to simulate the conditions of a front-corner crash, which can result in particularly severe injuries to drivers. In a front-corner crash, the impact bypasses most of the frontal crush zones designed to absorb some of the impact. So the passenger compartment takes a greater amount of the force of the crash and can buckle and collapse, severely injuring or killing a driver. Click the link to read our FAQ response about impact forces in a crash and how they affect your risk of injury.
Tests were conducted using 40 mph crashes, considerably less than the highway speeds at which many real-life crashes occur. The IIHS vehicle-to-vehicle crash test matched the subcompact cars against midsize cars, rather than against much heavier SUVs or light trucks. But even against the next vehicle size up, the subcompacts fared poorly. Of the 11 subcompact cars tested by the IIHS, only the Chevy Spark passed the test. The Chevy Spark received an “Acceptable” rating. The other 10 cars failed with ratings from “Marginal” to “Poor.” None of them could achieve the safety rating of “Good.” The Honda Fit and the Fiat 500 received the worst ratings.
The subcompact class was reportedly the worst –performing vehicle group so far evaluated for crash safety by the IIHS. Even in the Chevy Spark, the vehicle structure on the subcompacts came apart in the crash test. We note that when the vehicle structure fails in a crash, this greatly increases your risk of serious injury or death.
But other safety features besides the structures of the subcompact cars failed the test as well. Seatbelts failed to adequately restrain the crash test dummies in 7 of the 11 cars tested. And there were problems with the airbags in 9 of the 11 cars. In one of those vehicles, the airbag failed to deploy entirely. In others, the dummies’ heads missed the airbag and hit the instrument panel instead.
The physics and the kinetic energies of the crash situations are the bottom line. The kinetic energy of a vehicle in a crash is determined by its mass and velocity. Larger, heavier vehicles have more mass and therefore have more kinetic energy than a subcompact car, even if they’re going the exact same speed in a crash. The energy is indeed kinetic, and transfers itself onto the smaller vehicle and its occupants in the impact. And with the smaller crumple zones of the smaller vehicles, their occupants suffer the most from a crash. Size and weight do matter.