Drug-sniffing dogs can give police probable cause to root through cars by the roadside, but state data show the dogs have been wrong more often than they have been right about whether vehicles contain drugs or paraphernalia.

The dogs are trained to dig or sit when they smell drugs, which triggers automobile searches. But a Tribune analysis of three years of data for suburban departments found that only 44 percent of those alerts by the dogs led to the discovery of drugs or paraphernalia.

For Hispanic drivers, the success rate was just 27 percent.

Dog-handling officers and trainers argue the canine teams' accuracy shouldn't be measured in the number of alerts that turn up drugs. They said the scent of drugs or paraphernalia can linger in a car after drugs are used or sold, and the dogs' noses are so sensitive they can pick up residue from drugs that can no longer be found in a car.

But even advocates for the use of drug-sniffing dogs agree with experts who say many dog-and-officer teams are poorly trained and prone to false alerts that lead to unjustified searches. Leading a dog around a car too many times or spending too long examining a vehicle, for example, can cause a dog to give a signal for drugs where there are none, experts said.

"If you don't train, you can't be confident in your dog," said Alex Rothacker, a trainer who works with dozens of local drug-sniffing dogs. "A lot of dogs don't train. A lot of dogs aren't good."

The dog teams are not held to any statutory standard of performance in Illinois or most other states, experts and dog handlers said, though private groups offer certification for the canines.

Civil rights advocates and Latino activists say the findings support complaints that police unfairly target Hispanic drivers for invasive and embarrassing roadside vehicle searches.

"We know that there is a level of racial profiling going on, and this is just another indicator of that," said Virginia Martinez, a Chicago-based staff attorney for the Mexican American Legal Defense and Educational Fund.

Adam Schwartz, an attorney for the American Civil Liberties Union in Illinois, said the innocent suffer from unjustified searches.

"We've seen a national outcry about being frisked and scanned at airports," Schwartz said. "The experience of having police take your car apart for an hour is far more invasive and frightening and humiliating."

Police insist no racial profiling

The Tribune obtained and analyzed data from 2007 through 2009 collected by the state Department of Transportation to study racial profiling. But the data are incomplete. IDOT doesn't offer guidance on what exactly constitutes a drug dog alert, said spokesman Guy Tridgell, and most departments reported only a handful of searches based on alerts. At least two huge agencies — the Chicago Police Department and Illinois State Police — reported none.

The Tribune asked both agencies for their data, but state police could not provide a breakdown of how often their dog alerts led to seizures, and Chicago police did not provide any data.

That leaves figures only for suburban departments. Among those whose data are included, just six departments averaged at least 10 alerts per year, with the top three being the McHenry County sheriff's department, Naperville police and Romeoville police.

Romeoville did not respond to requests for comment, but Naperville and McHenry County authorities insisted there was no racial profiling and defended the performance of their dogs and handlers.

The McHenry County's sheriff's department had the most dog alerts, finding drugs or paraphernalia in 32 percent of 103 searches. In the eight searches on Hispanic drivers, officers reported finding drugs just once.

Since September 2008, Deputy Jeremy Bruketta has handled Sage, one of the McHenry County department's two drug-sniffing German shepherds. Officers sometimes come up empty-handed in searches of vehicles that clearly once contained drugs, he said, recalling a traffic stop in which a man, reeking of pot, had a marijuana stem stuck to his shirt but no drugs were found in the car.

In Naperville, 47 percent of searches turned up drugs or paraphernalia, though searches on Hispanic drivers turned up drugs in only one of 12 traffic stops, for a rate of 8 percent.

Officer Eddie Corneliusen, who handles Kairo, one of Naperville's two police dogs, also cited drug residue and said he's "confident that (the dog) is hitting on the odor of narcotics."

Inconsistent training and standards

Experts and trainers agree that residue could be to blame for some false positives.

In a cavernous, chilly building at the abandoned former Lake County Fairgrounds, Rothacker, the trainer, demonstrated the dogs' ability to pinpoint not only drugs, but also residue.

Rothacker, who works with some 60 area police dogs and handlers at TOPS Kennels in Grayslake, rubbed a bag of marijuana against a cinder block in the wall. Two German shepherds he trained alerted on the block with little hesitation, earning sessions of play with handlers who control the dogs' beloved chew toys.

But Rothacker said false alerts can't be blamed on residue alone.

Rothacker, who trained dogs for both Naperville and McHenry County, said many trainers use suspect methods and some handlers are "very lazy" about training their dogs. After initial intensive instruction for dog and handler, Rothacker offers twice-weekly training to handlers diligent enough to keep showing up, he said.

"The dogs are only as good as the handlers," he said.

Experts said police agencies are inconsistent about the level of training they require and few states mandate training or certification. Jim Watson, secretary of the North American Police Work Dog Association, said a tiny minority of states require certification, though neither he nor other experts could say exactly how many.

A federally sponsored advisory commission has recommended a set of best practices, though they are not backed by any legal mandate.

Illinois state Rep. Jim Durkin, R- Western Springs, sponsored a bill in 2007 that would have created a certification board responsible for setting standards that all police dogs would have to meet, but the bill died in a Senate committee after passing in the House. Durkin, a former Cook County prosecutor who referred to police dogs as "probable cause with four legs," said he may push the legislation again.

"This one makes sense," he said.

State Rep. Monique Davis wants the drug-dog issue vetted by a state panel on racial profiling. Davis, D-Chicago, co-sponsored a 2004 law to collect the police data. Seven years later, she said racial profiling remains a problem.