How the 2016 Volvo XC90 Could Reduce Off-Road Crash Injuries

Exploring the Tech Behind Volvo's Off-Road Crash Testing



Here's an off-roading statistic Jeep, Land Rover, and other makers of "serious" four-by-fours don't often mention: In Volvo's extensive 45-year study of real-world vehicle crashes, some 30 percent of them involve leaving the roadway -- unintentionally and often at considerable speed with dire consequences. Such incidents result in a higher likelihood of thorax/lumbar spinal injuries, and vehicle protection against these injuries lags behind the overall injury reduction over the past decade. The Swedish brand's next flagship soft-roader will endeavor to improve those statistics with new features aimed at reducing injuries in such unhappy off-roading incidents.

 

Back in 2007 Volvo devised a test in which the subject vehicle gets towed up to a steady speed of 80 km/h (50 mph) and then veers into a ditch with an angled culvert at the end. The left wheels leave the level roadway first, and then the whole nose hits the angled culvert. This launches the vehicle up into the air, and between that launch and the landing, the vertical load on the occupants' spines can top 10 g -- similar to the forces a fighter pilot experiences when ejecting from a struck plane.

Seven years of research and development involving crash tests like this and g-loading tests performed by an ABB robot (which itself costs about as much as one crash test) have led to a suite of technical solutions. First the myriad sensors currently present on most new cars are taught to recognize when the vehicle leaves the road. When this happens, the electric seatbelt retractors pull the occupants firmly into contact with the seats (just like those fighter pilots, who are always belted in tight). Then the seat designers took a page from the frontal-crash protection playbook and built in crumple zones to absorb the vertical shock.

To do this, they started by moving things out from under the seats -- no more stereo amps, bulky seat motors, etc., live in the area where you'd like your backside to go during a 10g event. This freed up 5.5 inches of space, the last 1.5 inches or so of which are absorbed by a sacrificial steel crush element in each front seat. (The rear seats do not provide this protection -- and owners should refrain from stashing bulky stuff under their front seats!) How much of this combined crush space you might use will depend on your mass and the severity of the impact. The result is a claimed 30-percent reduction in the likelihood of serious spinal injury in such crashes.

Two demonstrations of Volvo's "run-off road" test were staged during a recent press event at the company's Gothenburg headquarters, and the results were dramatic. In the first, the vehicle remained in a straight line and only deployed the frontal airbags. In the second (illustrated here), it came down on an angle and curved sharply left, deploying both the frontal (and knee) bags and the right-side curtains, which stay firmly inflated for roughly six seconds to continually provide protection in the event of multiple rollovers or other subsequent impacts. Exterior damage appeared superficial, and indeed a new enough XC90 involved in such an incident might be deemed repairable, but a completely destroyed left front wheel belies the impact force of the landing.

None of this testing is pursuant to governmental regulations in any market today. It's all in support of Volvo's stated goal of increasing safety to the point where nobody is killed or seriously injured in a new Volvo from 2020 onward.

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