Too much spin, not enough win. That's the takeaway from a Chicago Tribune examination of the safety benefits of Chicago's red light camera program.

A scientific study paid for by the Tribune found that the cameras — there are currently more than 350 throughout the city — have reduced dangerous "T-bone" crashes by 15 percent at those intersections. But it also calculated a 22 percent increase in rear-end accidents involving injuries, typically caused when a driver slams on the brakes to avoid running the red.

That pattern is consistent with other studies across the country.

The Tribune's researchers concluded that Chicago's red light cameras haven't reduced injury-related crashes overall.

Chicago has the nation's largest network of red light cameras, generating $500 million since 2002. But the city hasn't commissioned a similar study of its own to judge the system's effectiveness. Instead, Mayor Rahm Emanuel's administration has relied largely on a cursory before-and-after analysis of state numbers that inflate the program's effectiveness.

A change in the accident reporting threshold caused a 30 percent drop in the recorded number of overall crashes throughout Illinois, beginning in 2009. Using state numbers without making that and other adjustments, the city was able to boast of a 47 percent decrease in right-angle crashes at intersections where the cameras were installed.

Given the constant grumbling about whether the cameras are a safety initiative or a money grab, that was a handy number to have. But it's bogus.

This week's stories by Tribune reporters David Kidwell and Alex Richards also raise questions about how the city decided where to deploy cameras. Experts (and common sense) say the safety benefits are greatest when cameras are placed at intersections where crash numbers are relatively high. But almost half of the intersections in the Tribune study had fewer than four crashes per year before the cameras were installed.

The scientists concluded that cameras provided no safety benefit at low-crash intersections. What they have provided is $140 million in fines.

We have little sympathy for anyone who gets ticketed for running a red light, regardless of how many crashes have occurred previously at that particular intersection. The brake pedal is on the left, people. But if the program is truly about safety, then the cameras should go where they will prevent the most accidents.

Last year, the city's inspector general determined that only 42 percent of cameras were installed at intersections with the worst crash histories. And the Chicago Department of Transportation had no paperwork to show how it decided where the cameras would go. The IG's report called the city's management of the program "fundamentally deficient."

Chicago motorists already had plenty of reasons to be skeptical of the red light cameras. Federal prosecutors have charged a former city transportation official with taking up to $2 million in bribes to steer the red light contract to Redflex Traffic Systems Inc., the city's original vendor. The middleman in that alleged scheme has pleaded guilty.

In July, Kidwell and Richards reported on a series of dramatic spikes in the number of tickets issued by dozens of cameras. The city didn't know about the surges and still can't explain them, but it sure looks like they were caused by someone tinkering with the settings to trap more motorists.

That's all fodder for the money grab side of the debate, and Emanuel's opponents in the coming election are all over it. It's a free, easy shot — and Emanuel has no one to blame but himself.

Experts consulted by the Tribune criticized the city for its failure to conduct a professional evaluation of the largest red light camera program in the nation. The pseudo-analysis used by city officials to defend the program is "frankly embarrassing," one of the experts said.

Public confidence in the cameras depends on assurances that the system is improving safety and that it is fair. City officials don't have the data to make either of those assertions. Instead, they've been merrily spouting rosy numbers they hoped nobody would question. And they've been blindsided repeatedly by evidence that the system can't be trusted.

"They need to reimagine the entire program and do it well," says Joseph Hummer, chairman of the civil and environmental engineering department at Wayne State University. "Do it right this time."

Copyright © 2014, Chicago Tribune