by John Davis
Regardless of what you drive, auto accidents do happen. But figuring out why, and how, they happen, and how to keep them from happening again has never been an exact science. But as our FYI reporter Yolanda Vazquez has found out, we’re getting closer.
YOLANDA VAZQUEZ: Whether it’s a fender bender or a major accident, figuring out who’s at fault-- or who’s being truthful, is often tricky. That’s when accident reconstructionist Greg Sullenberger and Tracie Eckstein come on the scene.
GREG SULLENBERGER: …I generally am called by insurance companies, or law firms, or private individuals who are involved in a crash, or who are litigating a crash…
YOLANDA VAZQUEZ: To give us a better idea of how it all works, they set up a mock accident- in which they simulate a 90-degree collision of two cars at an intersection. Sullenberger gets out his gear-it includes everything from a leveling rod to a prism pole- surveying equipment that’s a must for any professional accident investigator.
GREG SULLENBERGER: …it’s all very basic…it’s 8th grade Newton’s laws of motions and high school mathematics and physics, but then there’s a lot of collision specific training that fully goes into understanding everything…
YOLANDA VAZQUEZ: With the surveying tools, they’re able to document all the evidence at the scene. That includes the braking marks on the roadway, the position of rest of both vehicles, and a braking test using an accelerometer.
GREG SULLENBERGER: … that tells me friction between tires and roadway surface so I can then use that to apply to a formula…
YOLANDA VAZQUEZ: Next, they take a close look at the damage to the vehicles- checking each tire’s tread wear and taking photographs.
A review of the seatbelts lets them know if there was any stretching or deformities present, but the most significant information usually comes from the car itself. Sullenberger plugs into the airbag control module, and its event data recorder. He uses software to analyze the data from the EDR—which can save up to 5-seconds or more of pre-crash data.
GREG SULLENBERGER: …gives me the speed, accelerator pedal position, brake pedal position, seat belt position-possibly several other parameters…
YOLANDA VAZQUEZ: …and other vehicle specifics like the delta v- which is the change in velocity in a crash.
TRACIE ECKSTEIN: …so if you have a Delta V of 30mph, that’s quite severe. If you have a Delta V of 5mph, you may have some neck pain or something like that, but it’s a fairly minor crash…
YOLANDA VAZQUEZ: The National Highway Transportation and Safety Administration recently issued a regulation to standardize all the data recorded by an EDR. This list shows what that includes. And if need be, Sullenberger will put together a 3-D animation to show how the crash occurred.
Accident reconstruction is also useful in developing recommendations for making highways and roads safer. Not to mention improving the safety aspects of future vehicle designs. Sullenberger and Eckstein both have law enforcement backgrounds with nearly 30 years of combined accident recon experience. But, they also emphasize the importance of training.
This video is from a high-speed crash testing seminar held in Pennsylvania last year. More than 300 police officers from 20 states attended-putting their reconstruction skills to the test.
GREG SULLENBERGER: …then we apply all the techniques and formulas and methodologies to confirm that what we learned in the classroom is true, because we do it in a controlled environment and prove to ourselves that we’re doing is correct and accurate.
YOLANDA VAZQUEZ: With cars becoming more and more technologically sophisticated, who knows what the future of accident reconstruction holds…But one thing’s for sure---this critical data is being used to make safety improvements for both motorists and their vehicles.