The art and technique of reconstructing car vs. bicycle, car vs. pedestrian accidents

Posted at: 09/12/2013 12:00 PM | Updated at: 09/12/2013 7:52 PM
By: Steve Flamisch

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A crash test dummy lays on the pavement Thursday during a training exercise hosted by the New York State Police.

Steve Flamisch / WNYT

ALBANY -- The trajectory of debris, the pattern of a victim's injuries, and what he or she was wearing are all critical clues in determining who is to blame in car-bicycle and car-pedestrian accidents, an expert said Thursday.

Ken Harmon, an adjunct instructor at the University of North Florida's Institute of Police Technology and Management, taught the "art and technique" of collision reconstruction to 35 members of law enforcement during a training program hosted by the New York State Police (NYSP).

"The really complex part in a pedestrian event is: Where was the pedestrian standing at the time he gets hit?" Harmon, a retired Tempe, Ariz. police officer, told NewsChannel 13. "That really illustrates who was probably more culpable for the event, and who was not."

Using a car seized during a NYSP investigation, and a crash test dummy, Harmon simulated a series of accidents in a closed parking lot on the W. Averell Harriman State Office Campus. After each collision, the investigators snapped photographs and took precise measurements.

In a real accident probe, they would try to determine if the driver was speeding and/or leaving the lane of travel; the location of the pedestrian at the moment of impact; and whether the driver had enough time to avoid the pedestrian.


Unlike other collisions, a car-bicycle or car-pedestrian accident often yields few physical clues, NYSP Technical Lt. Daniel Bates, the statewide program manager of the NYSP Collision Reconstruction Unit (CRU), told NewsChannel 13.

"It's one of those collisions that has very little evidence so it's probably the hardest type of collision to actually reconstruct because we don't have a lot of damaged parts from the car and other things," Bates said. "So we have to rely on what little evidence is actually at the scene."

If car parts do come off, and if the pedestrian was carrying a cell phone or other belongings, they generally scatter in a "cone of debris" in the direction the car was traveling, Bates said. Debris rarely lands behind the car.

NYSP Trooper Al Piraino, a road trooper assigned to Troop G, noticed an exception during the simulations. The dummy's hat generally shot straight up into the air and landed at the point of impact.

"If a pedestrian or bicyclist is wearing a hat, it’s usually found to be within close proximity of actually where they were struck," Piraino said.

Another clue yielded by the victim's clothing involves the material itself. During the exercise, the dummy's jeans left small blue marks on the hood and bumper of the car.

The victim's injuries often tell investigators whether the driver took evasive action, the experts said. If the driver applied the brakes, for instance, the victim is likely to suffer injuries that are lower on his or her body. The braking action causes the nose of the car to dip forward.


The end game is to determine who is at fault -- the driver, the pedestrian, or both -- and whether any charges should be filed. Investigators seek to determine whether the driver was exceeding the speed limit or drifting out of the lane of travel.

While a pedestrian who is not in a crosswalk or on a sidewalk does not necessarily have the right-of-way, a finding of fault may ultimately rest on whether the driver had enough time to avoid the collision.

"It's based upon the time and distance that the driver had to realize the pedestrian was there," Bates, of the NYSP, said. "That's what this is all about."

The course is funded by a grant from the New York State Governor's Traffic Safety Committee, Bates said. Twenty-three NYSP troopers are participating, along with a dozen members of other agencies including the Albany Police Department and the Warren County Sheriff's Department.



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