A Maple Valley man convicted of vehicular homicide has won a new trial after the state Court of Appeals dismissed a computerized accident-simulation program used in the trial.

"This is wonderful. It's fabulous," said John Rolfing Muenster, attorney for Michael Lee Sipin, who was convicted in 2002 after a traffic accident that killed his friend, David Taylor.

At issue was PC-Crash, a computer program distributed by Vancouver, B.C.-based MacInnis Engineering Associates. The program recreates traffic collisions using simulations and reconstructions.

"PC-Crash had not been validated for the purpose for which the evidence was offered, simulation and prediction of multiple-occupant movement within a vehicle during a multiple-collision accident," the Court of Appeals said in ordering a new trial. "There is no general acceptance in the relevant scientific community of the use of the PC-Crash program for the purposes to which it was put."

The court also ruled that the PC-Crash program can't be used in future cases "until such time as the relevant scientific community may reach consensus with respect to the validity and reliability of the PC-Crash program for the specific purposes here at issue."

The case involved a 2000 accident that occurred while Sipin and Taylor went for a ride around Maple Valley in Sipin's new sports car.

Witnesses said Taylor was driving when they left Sipin's house; the car hit a mailbox and a tree, ejecting both men. Taylor died soon after the accident, and Sipin suffered permanent brain damage.

Sipin was charged with vehicular homicide and convicted, despite his assertions that Taylor had been driving at the time of the accident. In the trial, PC-Crash was introduced as a computer simulation of the crash.

Muenster said the appeals court ruling "hit the nail on the head. This was the heart of it."

"PC-Crash had not been validated. It was not appropriate to use PC-Crash to decide who the driver was, and the identity of the driver was key to the case."

But Amy Freedheim, King County prosecutor in the felony traffic division, said the PC-Crash simulation was just a small part of the case and that it had been widely accepted that PC-Crash could be used in all kinds of cases.

"The jury was not blown away by the simulation. It was not the major thing in the trial," she said.

The major factor that led to the conviction, Freedheim said, was that the passenger door had melted onto Taylor's pants, indicating he was the passenger in the car.

She said the King County Prosecutor's Office will decide whether to retry the case. Sipin already has served about 18 months in jail, about half of his sentence.

Dennis McCurdy, the prosecutor who represented the county in the appeal, said he expects the case will be retried. At the time of the trial, he said, there had been no published court cases involving PC-Crash.

Bill Cliff, a senior engineer with MacInnis Engineering, said PC-Crash, built in Austria, has been in use in North America since 1996 and about 300 copies are used in the U.S.

"A lot of people have [PC-Crash], including the Washington State Patrol," he said, speculating the computer program might have been used incorrectly in this case.

He pointed out that the Court of Appeals ruled in another case involving PC-Crash in October, upholding the computer program.

But Boyd Allin, with MacInnis, said the PC-Crash program had not been validated for use in modeling what happens to those inside a car in a crash and that the use in this case was "an overextension of the capabilities of the model."

Susan Gilmore: 206-464-2054 or sgilmore@seattletimes.com