July 10, 2008 -- Traffic court in Warren, Mich., is a busy place. Sometimes, the courtroom is so crowded it's standing room only. Clutching their tickets, dozens of people line up at the cashier's windows to pay their fines. Many people are here because a cop said they didn't come to a full stop at a stop sign.
Though some drivers try to dispute the cops' versions of what happened, judges tend to believe the cops.
One police officer, David Kanapsky, generated many of those stop sign tickets.
As one judge explained to a woman who insisted she had come to a full stop, "Both statements cannot be true. I find Officer Kanapsky's testimony to be credible. He is an unbiased witness."
Is Kanapsky really unbiased? The more tickets he wrote, the more overtime he got. Last year, Kanapsky increased his pay by more than $20,000, most of which came from his time in court.
Kanapsky wouldn't talk to ABC News about this, but people he and his fellow officers ticketed did. After paying his ticket for running a stop sign, one man told us, "How do you fight it? It's your word against the cop. ... The judge is gonna believe the cop, not what you're saying."
Tickets for Profit?
In Michigan, cruising through a stop sign is a moving violation -- two points on your record. That drives up your car insurance costs. So to avoid the points, the judges let most everyone plead guilty to a lesser offense, "impeding traffic."
It's like an assembly line. Driver after driver agrees to pay the $135 fine; some even gratefully thank the judge for giving them a break. And then, one after the other, they pay their fines.
Give me a break.
Last year, the city of Warren made half a million dollars from these tickets.
One man who feels he was unfairly ticketed told ABC News, "It definitely seems like a money-making scam to me. If it was anyone other than our city government, it would be considered illegal."
Another man said, "They're just out there for the money. That's the bottom line."
Kanapsky's flood of stop sign tickets got the attention of Detroit's ABC affiliate reporter Heather Catallo. Her WXYZ investigative report on Kanapsky's ticketing blizzard led to a tip from a viewer that the cops weren't following the same rules they enforced on the rest of the city.
So Catallo took her cameras out to see if the cops stopped at the stop signs. Most, it turned out, did not.
"On two different days, we sat at the stop sign for several hours and we saw 25 cop cars roll through the stop sign," Catallo told "20/20." "Almost every cop car that we saw rolled through the sign. There were a few that stopped and there were a few that did what I call sort of a questionable stop, where they paused, and so we sort of gave them the benefit of the doubt. But 25 absolutely rolled through it."
Mayor: 'We Want to Make Sure the Road is Safe'
Her report caused a ruckus in Warren. Recently elected Mayor Jim Fouts, who promised reform if elected, called the ticketing "an unacceptable double standard."
"Citizens have to be treated fairly, and obviously police officers have to understand that they represent the law and they can't be above the law," Fouts told ABC News.
"We're here to enforce the law," he said. "We want to make sure the road is safe for the citizens. But we're not going to engage in trivial pursuit or technical 'gotchas' in order to make revenue."
Fouts hired William Dwyer, a veteran police official, as the city's new police commissioner. Dwyer had been on the job for five weeks when he told me the cops who didn't stop may have been going to the aid of another officer.
"It's not uncommon for an officer to hear a call for service to come out on a disturbance or family trouble. ... That's very common in law enforcement."
"Wouldn't they have their lights on?" I asked.
"Not necessarily. They would go as a backup," Dwyer said. "They don't necessarily have to have their lights and sirens on."
"But the tape showed cars doing it on the way back to the police station. Was there an emergency at the station?"
"I certainly can't justify officers going through a stop sign coming back to the station," Dwyer admitted. "Did some officers make mistakes? Perhaps so."
I also asked Dwyer about the thousands of tickets written by Kanapsky. "Doesn't that make it seem like this is just a moneymaking scam?"
Dwyer said no.
"When you are a traffic officer, that's your primary responsibility, to enforce the traffic code of the state," he said. "So it's not unusual for a traffic officer anywhere, in any department, to write 10 to 20 traffic violations a day, if not more."
Now, Kanapsky's been told not to write any more stop sign tickets. And the stop sign where he wrote so many?
After receiving so many complaints from drivers, the city of Warren conducted a study and concluded the sign's placement was -- surprise -- "incorrect due to the natural traffic flow in that area." The state agreed and the stop sign has now been changed to a yield sign!
According to the police, "A recent check of reported crash reports at that location show that between Jan. 16, 2008, and May 21, 2008, there have been no accidents reported. During that same time frame in 2007, there were four crashes reported. Not only has the sign location been corrected, but it has resulted in less traffic accidents."
That's good news, but it's unfortunate that so many people had to get tickets before it was fixed.
To all those cops who would punish us for doing what they do, I say, "Give me a break."
Producer Frank Mastropolo contributed to this report.