Professors study dilemmas in sustaining red light camera programs

August 13, 2013, University of Tennessee at Knoxville
This figure shows a list of measures and their effectiveness, safety impacts and efficiency impacts.

It's a common driving predicament: As you approach the intersection, the light is yellow. Do you hit the brakes or face a red light camera fine?

Some municipalities engineer their signals to force drivers into this situation in an effort to generate revenue from the cameras.

Professors at UT have analyzed this issue to determine if traffic control measures intended to boost red light revenue—such as shortening yellow light time or increasing the speed limit on a street—compromise safety.

The study by professors Lee Han, Chris Cherry, and Qiang Yang in the Civil and Environmental Engineering Department is published in this month's issue of Transport Policy journal.

Most municipalities acquire their systems through private vendors and pay for them either through a monthly flat rate or a portion of citations. Thus, the more successful red light programs are at improving safety by decreasing red light running, the less profitable they become. This creates a predicament for traffic engineers—meet financial guarantees to sustain the programs, or increase safety?

"Traffic engineers are facing an of balancing revenue generation to sustain their red light camera programs with their and efficiency goals," said Han. "This is a new conundrum for them."

The authors analyzed prior research related to four traffic signal measures—shortening yellow duration and/or lengthening all-red duration, shortening cycle length, increasing the speed limit and increasing high volume-to-capacity conditions such as with an unwarranted turn signal—and their impacts on red light running, safety, and efficiency.

Among their findings:

  • Shortening the yellow and/or lengthening the all-red, shortening the cycle length, and increasing the speed limit increased the chance of drivers running a red light.
  • Shortening the yellow and increasing the speed limit increased the chance of a crash.
  • Shortening the yellow and/or lengthening the all-red and increasing the speed limit did not impact efficiency of traffic flow.
  • Increasing high volume-to-capacity conditions increased the chances of traffic congestion at a signal but not the chances of running a red light or crashing.

According to the researchers, within the bounds of engineering design standards, there is room for traffic engineers to apply their judgment and develop the best signal-timing strategy. They note that while each strategy has its merits and faults, a combination of the strategies could possibly produce adequate revenue without causing traffic delays or congestion.

"One of the major challenges with implementing red light camera policy is the conflict of matching incentives of tangible revenue for industry and the municipality contrasted with external cost savings such as safety and congestion the value of which is not easily captured," said Cherry. "We hope the public sector and the public use our research to reflect on the motivations for changing signal operations."

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2.5 / 5 (2) Aug 13, 2013
Traffic engineers are facing an ethical dilemma of balancing revenue generation to sustain their red light camera programs with their traffic safety and efficiency goals

This shouldn't be a conundrum for the engineers. Safety first (and screw the managers that demand more reveue). I'm certain there are national standards for this sort of thing - even in the US.

If something happens and it is known that the city optimizes for revenue then the city will be sued (whether it falls in the categories that increased crashes or not won't matter) - and guess who will lose their job if safety was compromised: the engineer.
3 / 5 (2) Aug 13, 2013
I do delivering a lot in the city. The real hassle with lights at intersections is during low traffic circulation:

If one car is at a red light intersection waiting for the signal to turn green to cross the intersection the light will most likely change as the few, other cars are approaching their green light. They will need to wait for that one car to cross safely!!!

All drivers have to take a driving exam with knowledge on rule-of-the-road, including safe driving. As a result, one can figure out how to safely (for all concerned) cross an intersection??? Besides, after a certain hour during the day/night the light can blink red/green appropriately at the intersections. And, with our great "super" technology of cameras to catch speedster we do not have a camera technology to determine traffic flows in an upcoming intersection to vary the signal change as to a smooth flow of traffic???

Municipalities have no concern for drivers safety, smooth traffic flow, or environment impact.
not rated yet Aug 13, 2013
"Traffic engineers are facing an ethical dilemma of balancing revenue generation to sustain their red light camera programs with their traffic safety and efficiency goals," said Han. "This is a new conundrum for them."

Only in the mind of Han and the other ethically impaired.

I note that their findings did not include LENGTHENING the yellow light. The conundrum for the driver is whether there is adequate time to stop safely versus trying to "beat" the light. I believe it has been shown that lengthening the yellow allows drivers to both stop safely and proceed through the light depending upon the distance from the signal when it goes from green to yellow, resulting in fewer people running red lights and fewer intersection accidents. But guess what? Where red light cameras exist, they won't do that.
1.8 / 5 (5) Aug 14, 2013
So, you install something to make things safer... then you make things less safe so you can pay to make things safer...

So, if we generate revenue and fines from, say, litter sensors from people dropping things in areas other than trash receptacles, we should make sure to make the trash receptacles inaccessible to guarantee a certain minimum of garbage needed to avert just above that minimum of garbage...

So, if we generate revenue and fines from poorly manufactured pharmaceuticals, we should reduce inspections and oversight to increase the chance that malfeasance occurs so fines can be used to pay inspectors...

It sounds stupid no matter what the example.
1.5 / 5 (6) Aug 18, 2013
GMR, this is two for two that we agree upon today........What's up.... have you joined the conservative side????
not rated yet Aug 20, 2013
GMR, this is two for two that we agree upon today........What's up.... have you joined the conservative side????

I don't think of issues as "liberal" or "conservative," actually - I try and consider each issue from my own perspective.

If I end up on one side or the other, it's because somebody else has defined sides. I just have opinions that I try and make sure are considered. And people are free to ask me why I've come to conclusions, or hold certain opinions.

And I try not to hold any grudges. Even Nik could ask me a cordial question, and I'd answer - with him, all too often I find him in the middle of some self-aggrandizing statement, and I find it hard to hold my tongue.

I really should realize it's all a cry for help. People who need that kind of attention and plaudits at a nearly pathological level usually have extremely insecure self-images, covered with a thick layer of bravado.

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