The traffic stop began peacefully three hours into New Year's Day 2010, with the woman driving the SUV telling the officer that she hadn't been drinking and her husband merrily exclaiming he was the source of the alcohol smell.

But the situation soured when Steven Kotlinski, 55, stepped out to watch his wife's sobriety test, provoking the Mundelein officers to order him into the SUV. He reluctantly obeyed, but one officer said Kotlinski had obstructed his efforts. He ordered him back out, then tried to pull him out.

Next came the electric crackle of a Taser, a sound heard far more often in Chicago and many suburbs than it was just a few years ago.

A Tribune analysis shows Taser use has jumped fivefold in the city since 2008 and suburban agencies that were surveyed were on pace to double their use, as departments equipped more officers with the devices. Chicago police were deploying Tasers at a rate of more than twice a day in 2011.

And oversight has not kept pace with the explosion in use. Departments are on their own in developing policies on when and how electroshock devices should be deployed, with no state regulation.

In Kotlinski's case, the engineer at Abbott Laboratories was removed from his SUV and pinned in the snow. He lost control of his body as an "intense burning sensation" accompanied the surreal feeling that he was floating over the ground, he said. He roared about his heart condition, then begged in a faint wheeze for someone to call 911.

"Pain. I've never felt that way in my life," Kotlinski said.

They may bring pain, but the weapons save lives by reducing the use of guns or physical combat, police say. Civil rights advocates and experts on use of force counter that some officers deploy them too eagerly, spurring lawsuits and fomenting distrust of officers. The potential lethality of the weapons remains under debate, but critics point to hundreds of deaths that have followed their use as proof that electroshock devices should be seen as deadly weapons.

"It's a wonderful tool, when used properly," said Geoffrey Alpert, a University of South Carolina criminal justice professor who co-wrote a recent federal report on the weapons.

"But they've just got to be used judiciously, and in many departments, they aren't."

Like almost all states, Illinois does not track the weapons' use by local police, and departments have been left to monitor and govern electroshock devices with a patchwork of policies. In Chicago, the leap in the number of police carrying Tasers coincided with the scaling back of post-shock investigations by the Independent Police Review Authority.

Safety debate

Although no Illinois agency collects data on uses of force by police, figures provided to the Tribune by Mundelein and eight randomly selected suburban departments that use the devices show police are on pace to deploy them roughly twice as often in 2011 as they did in 2008.

Police in those departments used the weapons 35 times in 2008. By fall 2011, they had used them 56 times on the year. If that pace continued through December, the figure for 2011 would fall near 70.

Departments reported deployments at different levels of detail, and it was not clear in every case how a "use" or "incident" was defined. But the trend toward more frequent use was clear.

The rise has been steeper in Chicago. In 2009, officers logged 197 incidents. A year later, after hundreds more weapons were passed out, Chicago police reported 871 incidents. As of fall, the department was on pace for 857 uses in 2011, which works out to 2.3 per day.

The growth in the weapons' use should not come as a surprise, given their rise in popularity.

Several companies make electroshock weapons, which override the target's central nervous system by firing wire-tethered probes that deliver electrical jolts. Arizona-based Taser International makes the most popular models. About 576,000 of the devices are used by more than 16,500 law enforcement and military organizations, nearly all in the United States, said spokesman Steve Tuttle. Only 500 or so agencies used the weapons in 2000, he said.

In Illinois, a little fewer than half of the municipal police agencies that responded to a 2007 survey reported they were using electroshock weapons, according to the Illinois Law Enforcement Training and Standards Board, and more departments have since bought the weapons. Several suburban agencies contacted by the Tribune appear to have started using them in 2008 or 2009.

Taser International and police departments have faced lawsuits over safety. And though many fatalities following electroshock weapon use have been attributed to other causes, human rights group Amnesty International has counted 490 deaths after electroshock device use in the U.S. since 1990, said Debra Erenberg, Midwest regional director for the group. In some 50 cases between 2001 and 2008, coroners listed the weapons as a cause or contributing factor in a death, according to a study by the group.

Tuttle said the company has yet to be informed of a study proving the weapons can directly cause death. A study published last year by the U.S. Department of Justice found "no clear medical evidence that shows a high risk of serious injury or death from the direct effects" of the weapons. But that study also noted more research is needed to determine what role electroshock weapons can play in suspect deaths, especially in the case of unhealthy or intoxicated people.

The same limited study concluded the weapons reduce injury rates among police and civilians, compared with other types of force. But the report cautioned against overuse.

Split-second decision

Kotlinski's confrontation with police — captured on video and microphones — shows that a split-second choice to shock a suspect can sow long-term consequences. Lawyers for Kotlinski and Mundelein recently negotiated an undisclosed settlement to a federal lawsuit, and attempts by the Lake County state's attorney's office to prosecute him ultimately were unsuccessful.