ARLINGTON — A gentle nudge can cause a dizzying spin.

At 25 mph, the force of it almost passes for a parking mishap, a brief shudder in the car on contact. And that’s just the practice bump.

At 45 mph, it’s a full, stomach-churning spin-out with squealing tires and flying mud.

Every year, Snohomish County sheriff’s deputies must undergo refresher training on the PIT maneuver, also known as a pursuit intervention technique. It involves a targeted tap from a patrol car to the back bumper of a fleeing vehicle, designed to make the other driver lose control.

Pursuits are one of the most dangerous, high-risk and high-liability operations in police work. Police departments around the county have adopted stricter pursuit policies after fatal crashes and expensive lawsuits, including the cities of Everett and Bothell.

The sheriff’s office is reviewing all of its policies related to driving, spokeswoman Shari Ireton said.

A PIT maneuver is meant to stop a pursuit as soon as possible, with minimal injuries and property damage, said Sgt. Vince Linnell. Officers also can call off a pursuit for safety reasons, or have others deploy spike strips.

Linnell has run training on emergency driving operations for the sheriff’s office since 1994, and PIT maneuvers since 1998. He’s used PIT on seven drivers in his career, he said. Many longtime deputies have done more than that, though the maneuver is less common today than in past decades, he said.

“It’s all physics,” he said. “Everything rotates around the center of gravity.”

During a chase, deputies are allowed to use a PIT maneuver at their discretion up to 40 mph. Beyond that, they need a supervisor’s approval.

For practice Friday at the Arlington Municipal Airport, they used old patrol cars outfitted with steel bumper-covers. The tarmac was watered down to minimize the wear-and-tear on tires.

“It’s not violent if it’s done right,” Linnell said. “The goal is to put them, hopefully, in a ditch back-end first so they can’t get out.”

When it comes to the bump, there’s “about a foot of sweet spot you’re trying to hit,” he said. Gravity takes over once the fleeing car is moved about 20 degrees off path.

“In neither car do you feel a lot of trauma,” he said — if the technique is correct.

The training runs counter to a driver’s natural instinct to avoid a car crash at all costs, deputy Daryl Hansmann said. The faster the speeds, the deeper the spin, he said.

Deputy Judith Saarinen played the part of the would-be getaway driver. It was old hat for her, doing the runs over and over, but she advises her passengers not to jump in right after lunch. Everyone wears helmets and heavy-duty seat belts.

Part of the trouble is guessing where the impact will send the other vehicle, Linnell said. They can’t PIT someone off a bridge or into pedestrians. They also don’t want to end up with their back to a suspect.

“It’s all part of the training, and the real world,” he said.

Rikki King: 425-339-3449; rking@heraldnet.com.