Many drivers have felt the dread of seeing flashing police lights in the rear-view mirror. But where to pull over? There might be heavy traffic, a guardrail, a snowbank. Stopping immediately might seem dangerous.

But can a driver delay the stop and not get in trouble?

That's the question left dangling by the Minnesota State Patrol's admitted mishandling of a highly publicized incident on New Year's Eve, when a trooper jailed a Hudson, Wis., driver after ramming his van when he didn't stop right away. Instead, he drove a mile and exited the busy freeway.

The patrol admitted that the trooper violated policies, but it also maintained that Sam Salter could have pulled over safely on Interstate 94, despite his concerns that the snow-packed shoulder wasn't wide enough and that he had his children in the back of the van.

While Salter got some vindication, the mixed message put out by the patrol might have left some motorists confused about how much judgment they can exercise when pulling over. The Star Tribune consulted statutes and several experts in an attempt to answer the question with at least a little more clarity.

First, state law is unambiguous. A driver must "immediately" move to the right edge of the road and stop.

But pulling over "immediately," it turns out, does not mean slamming on the breaks, say experts. Nor does it mean stopping in a lane. Nor on a shoulderless bridge, just over a hill crest, nor on a blind curve. Most troopers waiting for speeders look for straight stretches to avoid problems.

Room for common sense

"This all gets back to common sense," said David Schultz, lead instructor of traffic officers at the Minnesota Highway and Research Center in St. Cloud. It involves common sense by both driver and officer. "Most cops use their judgment," he said.

But cops can make mistakes, and Sgt. Carrie Rindal made one on New Year's Eve, according to the State Patrol.

On the hunt for drunken drivers, she saw a van weaving within a lane, going 70 miles per hour in a 55-mph zone, and changing lanes without signaling just east of downtown St. Paul. When Salter didn't stop, Rindal concluded he was fleeing, even though he did not accelerate and signaled as he moved to the right lane. When Salter pulled to a curb on a side street, she rammed his van and arrested him. He spent 37 hours in jail. He registered zero on a Breathalyzer.

Rindal got a letter of reprimand, and the patrol paid Salter $9,500 rather than face a lawsuit.

"It's obvious there was improper behavior on the part of the trooper," said R. Scott McAllen, a retired trooper who was named national trooper of the year in 1990 by the International Association of Chiefs of Police. He is former vice president of the International Association of Accident Reconstruction Specialists.

"I had many people late at night that were really apprehensive to pull over at any spot, and they tried to find places to get out of traffic," he said.

Col. Mark Dunaski, chief of the patrol, said after the Salter case that the law states "immediately," but he added that drivers can "move over as quickly as possible, as quickly as it is safe." However, he said he understood that people at times "do things because they feel this is the right thing to do, and I am not going to fault them."

Be wary at night

Schultz, the police instructor, said he would pull over right away if he felt he could safely do so.

But he's given different advice to his wife: "I always tell [her that] if someone is attempting to pull you over in the middle of the night, turn your four-way flashers on so you are now acknowledging that you see him, and then I tell her to pull to the closest area that is lighted, with other people."

He's also said that she might call 911, to ensure she is being pursued by an officer. "There's probably a 99.9 percent chance it's a cop, but in case this is just some idiot that has got lights on his car, I don't want her to get hurt," he said.

Last Tuesday, Sgt. Curt Thurmes, a state trooper, had a reporter and photographer in his squad car when he clocked a Dodge Caravan going 76 mph in a 65-mph zone on Hwy. 52 in Dakota County. He swerved his Crown Victoria through the median in a 180-degree turn, splattering mud as he roared back up onto the pavement and gunned it, reaching 130 mph to chase down the van.

But once behind it, Thurmes did not turn on his emergency lights for a quarter mile, saying he didn't want the driver to stop in dangerous spots. He passed a curve, a guardrail, a crest of a hill and an intersection before activating the lights. He gave the 24-year-old Lakeville man a ticket.

"I once followed a car for 5 or 6 miles," Thurmes said. "He was talking on the phone, basically oblivious I was behind him. He didn't see the lights or hear the siren."

Bill Elkin, a retired Minneapolis traffic officer, said that when he pulled people over, he wanted them to start slowing down and put on a right turn signal. That let him know the driver knew he was behind and planned to stop.

McAllen, the retired trooper, said police must deal with some "bad people" on the roads. But he added: "The bottom line is we are not fighting Al-Qaida on the highway -- yet. The motoring public is paying our salaries for the service we are rendering these people, and the service should be done in a safe and courteous matter."

Staff researcher John Wareham contributed to this report. Randy Furst • 612-673-7382