Utah cops train to investigate auto-pedestrian hit-and-runs

Cops from police departments around the valley gathered at the end of a lonely road in west Salt Lake City on Wednesday to watch a crash test dummy get repeatedly pummeled by old cars.

It was part of a class on "accident reconstruction," the forensic science that allows investigators to determine exactly what happens in the chaotic moments right before a car crash.

Propped up on a length of PVC pipe, the crash test dummy, clad in a collared T-shirt and blue jeans, waited with its eyes closed, ready for impact. An old black Toyota Corolla, donated by a local towing company, came tearing down the road at 36 mph and skidded headlong into the dummy.

The impact was so violent that it knocked the dummy's boots clean off its feet and sent it soaring some 40 feet through the air.

When the Corolla finally skidded to a stop, a dozen cops, mostly accident reconstructionists in training, scurried across the road toward the car. They marked the pavement with bright green spray paint, collected evidence from the vehicle and examined the dummy's body.

This training session and others like it are designed to help accident reconstructionists investigate real-world accident scenes when they don't have the benefit of having seen the accident take place.

Accident reconstruction has become an increasingly important job in recent years as the hit-and-run rate in auto-pedestrian collisions has jumped, said Salt Lake City police Sgt. Tom Potter, one of the experts teaching the class.

Arriving at the scene of a hit and run, an accident reconstructionist will measure the length of the skid marks and the distance a body travelled from the collision, information he can use to prove that a hit-and-run driver was speeding, for example.

Potter has been an accident reconstructionist for 12 of his 16 years on the force.

"I'm kind of a bookworm, kind of a math geek," he said. "Most police officers don't become police officers to do math or applied physics, but the ones that do need to be good at what they do."

Earning accident reconstructionist accreditation requires officers to spend hundreds of hours studying math and physics. "You have to be good at math. You have to be able to apply it," said Officer Tim Stumm, a student at the class who is one of eight accident reconstructionists in the Salt Lake City Police Department.

"I like piecing it all together," added Stumm, who was part of the investigation into the hit-and-run crash that critically injured a 5-year-old girl last month.

The girl was crossing 400 South at 1000 West at about 9:40 p.m. on May 30 when she was struck by a vehicle, which did not stop, according to police.

The identity of the driver is still unknown; the girl remains in intensive care at a hospital.

hstevens@sltrib.com

Twitter: @Harry_Stevens —

Ouch!

O Check out video of the crash tests online. > sltrib.com.