Investigators will probably spend several weeks investigating the Wednesday pileup on I-215 that killed three people in dense morning fog.

Among those investigators is a team from the National Transportation Safety Board, which is mostly interested in determining ways to improve driving safety in light of the problems caused by the fog and road conditions. State investigators will concentrate on liability issues to determine if any charges or citations will be filed."On these more complicated kinds of accidents, the troopers take all of the facts from the investigation in and sit down with the county attorney," said Utah Highway Patrol spokesman Gary Whitney.

"In a less complicated accident they might issue citations at the scene, but before doing that in this case they take all of the witness statements and crews look over safety equipment and interview all of the drivers," Whitney said.

A special accident investigation team will reconstruct the accident site. "Sometimes it takes a couple of weeks to finish that," he said.

Five pileups within a two-mile radius tangled 52 vehicles, killing three people. Three others remained hospitalized in critical condition, one in serious condition and one other was listed in fair condition Friday morning.