AARoads Forum

Please login or register.

Login with username, password and session length
Advanced search  


New rules for political content in signatures and user profiles. See this thread for details.

Author Topic: Chicago red light cameras provide few safety benefits  (Read 1744 times)


  • *
  • Offline Offline

  • Posts: 10840
  • Mr. Accelerator is our friend; Mr. Brake is not.

  • Age: 43
  • Location: Joliet, IL
  • Last Login: Today at 07:56:50 PM
Chicago red light cameras provide few safety benefits
« on: December 19, 2014, 09:29:37 AM »

Tribune study: Chicago red light cameras provide few safety benefits

Behind paywall, but here's the gist of the article.

Chicago's red light cameras fail to deliver the dramatic safety benefits long claimed by City Hall, according to a first-ever scientific study that found the nation's largest camera program is responsible for increasing some types of injury crashes while decreasing others.

The state-of-the-art study commissioned by the Tribune concluded the cameras do not reduce injury-related crashes overall undercutting Mayor Rahm Emanuel's primary defense of a program beset by mismanagement, malfunction and a $2 million bribery scandal.

Emanuel has credited the cameras for a 47 percent reduction in dangerous right-angle, or "T-bone," crashes. But the Tribune study, which accounted for declining accident rates in recent years as well as other confounding factors, found cameras reduced right-angle crashes that caused injuries by just 15 percent.

At the same time, the study calculated a corresponding 22 percent increase in rear-end crashes that caused injuries, illustrating a trade-off between the cameras' costs and benefits.

The researchers also determined there is no safety benefit from cameras installed at intersections where there have been few crashes with injuries. Such accidents actually increased at those intersections after cameras went in, the study found, though the small number of crashes makes it difficult to determine whether the cameras were to blame.

Maybe it's all about the $$$.

The finding raises questions about why the city installed cameras in so many places where injury-causing crashes were rare nearly 40 percent of the 190 intersections that had cameras through 2012, the Tribune found.

"The biggest takeaway is that overall (the program) seems to have had little effect," said Dominique Lord, an associate professor at Texas A&M University's Zachry Department of Civil Engineering who led the Tribune's study.

"So the question now is: If we eliminate a certain type of collision and increase the other and overall it stays the same, is there an argument that it is fair to go with the program?" Lord said. "That is a question that I cannot answer.

"Just the elected officials can answer for that."

Emanuel declined interview requests. His top transportation experts acknowledged flaws in the city's statistics but said the Tribune study reinforces their own conclusion that cameras are helping.

Rahm is of course, full of lies and bullshit.

Several national traffic experts consulted by the Tribune called the study a valid examination that largely mirrors the results of similar scientific efforts conducted around the country that found moderate decreases in T-bone crashes coupled with increases in rear-enders as drivers hit the brakes to avoid camera-generated tickets.

The study findings also dovetail with the Tribune's examination of how short yellow light times at Chicago's traffic signals raise the stakes for drivers.

Prompted by Tribune reporting, Emanuel officials recently admitted to the city inspector general that they had quietly dropped the threshold for what constitutes a red light camera ticket, allowing the tickets even when cameras showed a yellow light time just under the three-second federal minimum standard. That shift earlier this year snared 77,000 more drivers and $7.7 million in ticket revenue before the city agreed to change the threshold back.

Now the Tribune has learned that Chicago's long-standing reliance on using the lowest possible yellow light time under federal guidelines is out of step with other major cities in the country and a growing body of research that suggests short yellows and red light cameras are a dangerous combination.

"Of course that is going to lead to more accidents, especially rear-end accidents," said Timothy Gates, a Wayne State University associate engineering professor whose research is being used to set new nationwide guidelines calling for longer yellow lights.

"Since being launched more than a decade ago, the red light camera program has been a critical part of our efforts to improve the safety of our streets," Scheinfeld told the assembled aldermen. "The most recent crash statistics available from the state show that at intersections with red light cameras, the number of dangerous T-bone, angle crashes decreased by 47 percent between 2005 and 2012."

Given those numbers, the effectiveness of red light cameras would be difficult to dispute. But a half-dozen traffic engineering experts interviewed by the Tribune all agree that simple before-and-after comparison is not an effective measure. It doesn't account for changes in traffic flow because of the economic recession, or the improved safety of automobiles or any number of factors that have brought down crash numbers throughout the nation.

And most important, experts say, it doesn't account for any significant changes in the way accidents are reported to state transportation officials.

For instance, in 2009 the Illinois Department of Transportation changed the threshold for reporting property damage accidents to $1,500 in damage from $500, a rule change that prompted accident reports statewide to plummet by nearly 30 percent. That change alone renders the city's safety claims invalid, experts say.

"The city's study is worthless, making no adjustments for any potential bias," said Joseph Hummer, professor and chairman of civil and environmental engineering at Wayne State in Detroit. He also noted that, for some sites, the city used 2005 data in the "before" section of its analysis even though the cameras had been installed there in 2003 and 2004.

The City lying so they could have this system?  Nah, where do you think you are, Chicago?

Ald. Anthony Beale, 9th, chairman of the council Transportation Committee, said the city's numbers come as no surprise: "Those numbers the city uses have never made any sense. Of course they are skewing the numbers."

"That program needs to be stopped. It needs to be frozen to give us time to re-evaluate everything," Beale said. "This is just more proof that this entire program is strictly to generate revenue and always has been."

In an effort to assess the program's effects more realistically, the Tribune collaborated with Lord and another well-known researcher from the Texas A&M Transportation Institute, Srinivas Geedipally, to conduct an analysis using the latest scientific tools.

The $14,000 study used data gathered by the Tribune under the guidance of traffic safety experts around the country. The Tribune's work was also approved by Lord and Geedipally, who have published dozens of analytical papers on traffic safety, including red light camera systems, and worked as consultants to state and federal government.

The Chicago study by Lord and Geedipally acknowledges that the number of injury-causing accidents decreased at intersections after red light cameras were added, but it also notes that this simple comparison fails to account for other factors that affect a region's crash rates, such as changing economic conditions.

To determine the impact of red light cameras specifically, the researchers used a statistical technique called the empirical Bayes method that is commonly employed to evaluate traffic safety interventions. By analyzing data from intersections without red light cameras, they could predict how many crashes would have occurred at camera intersections if the equipment had not been installed.

The study included 90 of the 190 intersections in Chicago where cameras were operating during the study period. All 90 used in the study were four-leg intersections where cameras came online between 2008 and 2009. The Tribune also collected detailed Illinois crash data at each intersection for three years before and three years after the cameras were installed, as well as similar information for a control group of 59 intersections never equipped with cameras.

Lord and Geedipally used that data to conduct their analysis, the largest such study conducted on a single red light camera program in the United States.

The study results showed red light cameras are responsible for "a non-significant increase of 5 percent in the total number of injury crashes, a statistically significant reduction of 15 percent in angle and turning injury crashes, and a statistically significant increase of 22 percent in rear-end injury collisions," the authors wrote.

In raw numbers at the 90 intersections included in the study, the researchers concluded the cameras prevented as many as 76 right-angle crashes and caused about 54 more rear-end injury crashes. The study said that without the red light cameras about 501 angle crashes would have occurred and only 425 were reported. It also said that there were 296 rear-end injury crashes, and there would have been only 242 had the cameras never been installed.

There were 1,064 crashes reported in the three years after the 90 intersections were "treated" with red light cameras, the study noted.

"The analysis results show that if the treatment had not been used, the expected number of the crashes would have been 1,016 crashes," the study said. "In other words, it is estimated that RLCs (red light cameras) increased the crashes by 5 percent."

Because that 5 percent increase was considered within the study's margin of error, Lord and Geedipally said the increase might have happened just by chance.

The Tribune study did not address the cameras' impact on fender benders where no injuries were reported.

Seems as though the cameras really do nothing other than generate revenue.

The results of the Tribune study closely track those of a 2005 analysis of red light cameras commissioned by the Federal Highway Administration that used identical scientific methods to analyze 132 intersections in seven cities throughout the country. That study found a 16 percent decrease in right-angle injury crashes and a corresponding 24 percent increase in rear-end injury crashes.

The federal study went even further and assigned dollar damage estimates to the various kinds of crashes to conduct a cost-benefit analysis between rear-enders and the typically more dangerous T-bone crashes.

"The economic analysis examined the extent to which the increase in rear-end crashes negates the benefits for decreased right-angle crashes," the 2005 study concluded. "There was indeed a modest aggregate crash cost benefit of RLC systems."

Enough for me to say that these systems should be banned on a national level.

Other experts said the Tribune findings make it clear that nothing less than a complete re-examination of the city's program can solve the problems.

"My feeling is that they should conduct a re-evaluation of every intersection where a camera is installed and look at the crash numbers for each of them," said Raghavan Srinivasan, a senior transportation research engineer at the University of North Carolina Highway Safety Research Center. "All the research shows that the higher the rate of right-angle crashes to begin with, the more benefit the cameras provide."

Plus: Study: Safety Effects of the Red-Light Camera Enforcement Program in Chicago, the actual study itself.
"If you think this has a happy ending, you haven't been paying attention." - Ramsay Bolton

Illinois: America's own banana republic.


  • *
  • Offline Offline

  • Posts: 11179
  • Age: 45
  • Location: South Jersey
  • Last Login: Today at 06:51:09 PM
Re: Chicago red light cameras provide few safety benefits
« Reply #1 on: December 19, 2014, 10:08:54 AM »

Tribune study: Chicago red light cameras provide few safety benefits

Chicago's red light cameras fail to deliver the dramatic safety benefits long claimed by City Hall, according to a first-ever scientific study that found the nation's largest camera program is responsible for increasing some types of injury crashes while decreasing others.

I was going to say there's been many studies about red light cameras.  I'm not sure why this is claimed to be the first.  Then the article stated this...

The results of the Tribune study closely track those of a 2005 analysis of red light cameras commissioned by the Federal Highway Administration that used identical scientific methods to analyze 132 intersections in seven cities throughout the country.

So it's not even the 1st ever study, as documented in their own story.

Anyway...the study (or studies) conclude pretty much what has been concluded throughout the country.

NJ recently ended their pilot program, and will not renew it or allow for a permanent program until the study results are published by NJDOT.  There's not much political will, at least for now, to restart the program, which requires the Governor's blessing.


Opinions expressed here on belong solely to the poster and do not represent or reflect the opinions or beliefs of AARoads, its creators and/or associates.