Small Overlap Crash Test
The influx of all the amazing new electronic safety aids and crash avoidance systems found on-board new cars has been exceptional. There is no doubt that these systems are helping save lives and minimising injury. There has been one part of the latest car crash testing regime that the Insurance Institute for Highway Safety (IIHS) has brought in as part of their testing in order to help make cars safer.
The IIHS is an independent, non-profit scientific and educational organization dedicated to reducing deaths, injuries and property damage from motor vehicle crashes through their ongoing research and evaluation, and through the education of consumers, policymakers and safety professionals. The IIHS is funded by auto insurance companies and was established back in 1959. Its headquarters is in Arlington, Virginia, USA. A lot of what the IIHS does is crash test cars in a variety of ways to gather data, analyse the data, and observe the vehicles during and after the crash tests to quantify how safe each car is. The results and findings are published on their website at IIHS.org. Car manufacturers have been forced to take these tests seriously because, at the end of the day, these results matter and will affect car sales as the public become informed about how safe their cars will likely be in the event of an accident.
Since 2012, the IIHS has introduced a couple of new tests that they put the vehicles through to see how safe they are in an event of small overlap collision. The driver-side small overlap frontal test was brought about to help encourage further improvements in vehicle frontal crash protection. Keeping in mind that these IIHS tests are carried out using cars with left-hand-drive, the test is designed to replicate what happens when the front left corner of a vehicle collides with another vehicle or an object like a tree or utility pole. This crash test is a challenge for some safety belt and airbag designs because occupants move both forward and toward the side of the vehicle from the time of impact. In the driver-side small overlap frontal test, a vehicle travels at 40 mph (64 km/h) toward a 5-foot-tall rigid barrier. A Hybrid III dummy representing an average-size man is positioned in the driver seat. 25% percent of the total width of the vehicle strikes the barrier on the driver side.
Most modern cars have safety cages encapsulating the occupant compartment and are built to withstand head-on collisions and moderate overlap frontal crashes with little deformation. At the same time, crush zones help manage crash energy to reduce forces on the occupant compartment. The main crush-zone structures are concentrated in the middle 50% of the front end. When a crash involves these structures, the occupant compartment is protected from intrusion, and front airbags and safety belts can effectively restrain and protect occupants.
However, the small overlap frontal crashes primarily affect a vehicle’s outer edges, which aren’t well protected by the crush-zone structures. Crash forces go directly into the front wheel, the suspension system and the firewall. It is not uncommon for the wheel to be forced rearward into the footwell, contributing to even more intrusion into the occupant compartment, which often results in serious leg and foot injuries. To provide effective protection in these small overlap crashes, the safety cage needs to resist crash forces that haven’t been amplified, concentrated on one area or aren’t tempered by crush-zone structures. Widening these front-end crash protection structures does help.
The IIHS also performs the passenger-side small overlap frontal test. The passenger-side test is the same as the driver-side test, except the vehicle overlaps the barrier on the right side. In addition, instead of just one Hybrid III dummy, there are two — one in the driver seat and one in the passenger seat.
Automotive manufacturers initially responded to these driver-side small overlap test results by improving vehicle structures and airbags, and most vehicles now earn good ratings. However, IIHS research tests demonstrated that those improvements didn’t always carry over to the passenger side. Discrepancies between the left and right sides of vehicles spurred the IIHS to develop a passenger-side small overlap test and begin issuing passenger-side ratings in 2017.
It is good that vehicle safety always seems to be on the improve and, with each new model, the new-car buyer can expect a safer vehicle. Thanks to crash testers like the IIHS, ANCAP and Euro NCAP, we are experiencing safer cars on our roads.
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