The jury trial for the man whose truck slammed a Greyhound bus killing seven passengers Dec. 18 almost ended in mistrial when an important witness became so stressed by the ordeal that she could not testify.

That, in turn, left the defendant choosing to change his not guilty plea to "no contest" rather than see the ordeal continue.Robert W. Williams, 47, 6885 S. Redwood Road, West Jordan, began in the trial by pleading guilty to one count each of failing to keep a log book and driving on a suspended license. He pleaded not guilty to the third charge of driving too fast for conditions.

A four-member jury was selected to hear the case surrounding the speeding charge but was never told the truck Williams was driving had hit an oncoming Greyhound bus - just that it had gone out of control and left the highway. The jury's charge was to determine whether Williams was guilty of driving too fast for conditions at the time.

A storm that dropped several inches of snow was blowing into the area along I-80 near the Utah/Wyoming border as Williams drove from Evanston toward Salt Lake City at about 9:25 a.m. Utah Highway Patrol trooper Clark Lund said the truck was partially airborne and traveling between 52 and 58 mph as it careened down the embankment in the median toward the oncoming bus. That conclusion was reached from measurements taken the day of the accident combined with observations of conditions at the scene used several months after the accident to determine Williams' speed.

Prosecutors worked to convince the jury that Williams' speed was too fast for the conditions.

Williams said he was going only 45 mph and lost control of his truck when a "blue car," which had more or less paced the truck since Evanston, passed him and began to fishtail, prompting Williams to take evasive action and drive onto the shoulder of the road.

"I left the road on purpose to avoid the car," Williams said, adding that he was knocked unconscious when his semitrailer truck's wheels slipped off the pavement into the mud. The truck then crossed back over the westbound lanes and dove over the steep median embankment into the eastbound Greyhound.

"At the scene, the driver of the blue car said she may have been responsible for the accident," Lund said. But the statement then didn't change the trooper's opinion that Williams had been traveling too fast.

The trial was winding down when deputy Summit County Attorney Terry Christiansen called on Sheila Marshall, the driver of the blue car, to testify. Her attorney approached the prosecutor's table and told 3rd Circuit Judge Edward A. Watson that Marshall was so physically and mentally stressed that she probably could not even walk up the steps to the courtroom.

The jury was excused from the courtroom as defense and prosecution attorneys met with the judge in his chambers and while he spoke to Marshall. "She is emotionally, physically and mentally unable to testify today," the judge said after the recess. The two options were to declare a mistrial and start the proceedings over from scratch or wait possibly two weeks for Marshall to be well enough to testify.

"We would have to have her testimony to have a fair trial, which could take weeks," Watson said.

Both options spelled delay for Williams, who asked the judge to allow him to change his plea on the speeding charge to "no contest," which subjects him to the same sentencing as if he had pleaded guilty without pinning him with any admission of guilt or civil liability.

"This has been weighing on his mind for quite a period of time and he's reached the point where he just needs to have it done," said Williams' attorney, Scott Little.

Restitution may have to be attached to Williams' sentence, the judge said. Watson scheduled the sentencing for May 15 at 11 a.m.