IIHS Developing Virtual Testing to Prevent Neck Injuries – Safety

Marcy Edwards, senior research engineer of the Insurance Institute for Highway Safety (IIHS), recently announced the institute is developing a path for the long run of IIHS rear-impact testing.

IIHS’ long-term goal of the testing is to give you the option to guage how well each combination of a seat and head restraint protects people in a wide range of seating positions and crash scenarios. 

Getting there may be a multi-step process and would require the usage of virtual testing with computer models in addition to the traditional tools utilized in its original head restraint test.

IIHS added it should need the assistance of scientists developing detailed computer models of the human body and the cooperation of car manufacturers.

How IIHS Got Here

When IIHS began rating head restraints in 1995, it began with the fundamentals. Neck injuries in rear impacts occur when the top lags behind the accelerating seat and torso. This lag can often be prevented by good head restraint geometry, so IIHS’ first evaluations were measurements using a dummy representing a Fiftieth-percentile man.

A restraint needs to be at the very least as high as the top’s center of gravity, or about 3½ inches below the highest of the top. The backset, or the space from the back of the top to the restraint, needs to be as small as possible.

In 1995, only 3% of the top restraints IIHS evaluated received good geometric rankings, while 82% were rated poor. 

IIHS’ rankings led manufacturers to listen to those measurements long before a 2010 government standard made good geometry a legal requirement.

Good geometry is mandatory, nevertheless it’s not sufficient. Seats can differ in other ways too, akin to structure placement, seatback stiffness, and energy-absorbing properties, all of which may affect outcomes for occupants.

In 2004, IIHS added a dynamic test for any vehicle with a very good or acceptable geometric rating to guage how well the seat and head restraint managed crash energy and occupant motion.

This test consisted of a simulated rear impact with the vehicle seat mounted to a sled. A special dummy often called BioRID, which has a practical spine, was buckled within the seat. The heartbeat utilized in the test was such as a rear-end crash with a velocity change of 10 mph, or a stationary vehicle being struck at 20 mph by a vehicle of the identical weight.

The mix of IIHS geometric rankings and its dynamic tests allowed it to discover probably the most effective head restraints. In a study of real-world crashes, injury rates were 15% lower for vehicles with good rankings compared with those rated poor, while long-term injuries, or those lasting three months or more, were 35% lower.

Beyond BioRID

Since IIHS began dynamic testing, manufacturers have gotten superb at designing seats for the ten mph velocity change, and today’s vehicles all perform well in that test. Nonetheless, there are still differences in real-world performance.

Insurance claims data collected by my colleagues on the Highway Loss Data Institute suggest that injury rates in rear-ended vehicles with good head restraint rankings vary widely.

So how can IIHS design a brand new evaluation to raised differentiate amongst restraints?

One relatively easy update it intends to make is so as to add a second dynamic test with a bigger velocity change since many real-world front-to-rear crashes occur at higher speeds.

By adding a 15 mph test on top of the ten mph one, IIHS will give you the option to glean more information and encourage further progress. It plans to launch a brand new rating program based on the 2 tests inside the subsequent yr or two.

Beyond test speed, other variables are harder to tweak. As is the case with all crash test dummies, BioRID has limited capabilities — for instance, it’s only valid for fore-aft motion and lower-severity crashes — and doesn’t represent the variety of the driving population. While it’s a powerful tool with something that closely resembles a human spine, it represents the precise spine of a Fiftieth-percentile male.

Real-world injury data tells IIHS that girls are more likely than men to suffer neck injuries in crashes, nevertheless it doesn’t really know why. Researchers in Sweden are currently developing a female dummy to be used in rear-impact testing, which could someday help evaluate protection for ladies specifically.

Nonetheless, irrespective of how sophisticated, physical dummies can’t capture soft tissue and nerve damage, which can play a job in whiplash injuries and within the differences between men’s and ladies’s susceptibility to them.

Perhaps more importantly, any physical dummy, male or female, represents only one particular body type. 

Alternatively, computer models of the human body, that are currently under development, may very well be more easily varied to represent a spread of body types and injury risk aspects.

Virtual testing with these models could someday soon provide IIHS with the flexibility to see how seats and head restraints function for many various people sitting in numerous positions, based on Edwards.

IIHS’ Path Forward

How can IIHS go from physical tests performed on actual seats to a much wider set of tests performed virtually?

One big challenge is that while IIHS can exit and buy vehicles with physical seats to check, it cannot purchase computer models of those seats. Those models are the mental property of the manufacturers, so IIHS needs its cooperation.

At the identical time, it should must structure this cooperation in order that it doesn’t compromise the independence of the testing program or the trust consumers place in the outcomes.

IIHS allows established manufacturers to conduct tests based on its protocols after which supply it with video and other data in order that it could actually confirm the outcomes and assign rankings. IIHS randomly audits those manufacturer-conducted tests by repeating a few of them in its facility to make certain the outcomes match up.

IIHS said it intends to construct on that model because it branches out into virtual testing.

IIHS is planning to include virtual tests into its head restraint rankings in stages. As a primary step, it should give manufacturers the choice of submitting virtual test data for IIHS’ recent 15 mph test and its established 10 mph test. This phase will help IIHS get accustomed to working with virtual test data.

Later, IIHS will expand the variety of required test scenarios, potentially various things like speed, seat position, and occupant position — for instance, a passenger leaning forward attributable to hard braking or a driver looking down at a phone of their lap.

Its plan is to eventually expand the required virtual tests to incorporate scenarios that may’t be tested in the true world due to the restrictions of the dummies and other tools IIHS has. That is where it should give you the option to guage performance with occupants of various body types and in addition in numerous positions that may’t be achieved by a physical dummy.

To make certain the virtual results for all these different test scenarios match reality, IIHS will conduct physical tests for a few of them. 

Replicating some results after which ensuring the identical seat and dummy or human body models are used throughout the virtual evaluation will help it validate all the outcomes, including those for scenarios it could actually’t physically test.