Federal Study Shows Red Light Cameras Ineffective

A lot of people who oppose speed cameras actually support red light cameras. On the surface, this makes sense. After all, the danger of running a red light (read my analysis of red light running here) can be envisioned a lot easier that the alleged danger of driving 1 mph above an arbitrary limit. Compared to speeding, a red light violation is a little more clear cut if you have good video. That still doesn’t overcome all of the other weaknesses and problems with red light cameras and photo enforcement, but that’s a topic for another day.

Red Light Crash Data

Red Light Crash Data

Most people don’t know that in 2005 there was a federal study by the Federal Highway Administration that evaluated red light cameras and concluded that red light cameras are ineffective. Numbers from the report are to the right.

As presented, the numbers look compelling. It looks like cameras may be effective. If you treat all accidents the same and all injuries the same though, the numbers do not look as impressive. In the real world, it doesn’t matter if an accident was an angle collision or rear-end, and it doesn’t matter how you get your injuries. So let’s look at the data when you treat all accidents and injuries the same.

Crash Data Totals

Crash Data Totals

Now we can really derive some meaning. Total non-injury accidents declined only 0.1%. Injury accidents declined less than 5%. The effectiveness is truly underwhelming, definitely within a margin of error, and hardly worth the fuss, effort, and overhead.

While some may argue that RLCs are worth it for a 5% reduction in injuries, the logical response would be to ask if there are any other alternatives that offer a better result? The answer is definitely yes! Adjusting the light timing has been proven extremely effective. According to Mesa traffic engineer Alan Sanderson and Brenda Black of the Mesa PD, adding a second of yellow time to traffic lights reduced violations by 73% and lead to a “major drop” in accidents. While some expected the reduction to be temporary until traffic adjusted to the longer times, it was found that the effects were permanent and lasting. This makes sense, as it is my theory that most red light violations are not based on ill intent, but rather bad judgment calls, and an extra second of leeway provides some relief to those of us who don’t always make the best decisions, while making the road safer for everyone.

Revenue Or Safety?

Let’s take a look at the ubiquitous question: Are RLCs about revenue or safety? Clearly if the best case scenario is a mere 5% reduction in injuries, the answer points to revenue. And when you consider that most RLC programs are initiated by city councils and police departments rather than traffic engineers, you have to wonder where the logic is in having people other than traffic engineers decide how to make roads and intersections safer and decide that photo enforcement is the best solution. PRS has yet to encounter a photo enforcement program that was implemented at the behest of a traffic engineering department. Most cities have traffic engineers on staff who are available for consultation and who can do studies and who know what traffic calming measures are available, but instead, these councils and police departments think they know better despite not having the knowledge and training of real traffic engineers. Let’s not fool ourselves, it all comes down to the love affair with “easy” money. When the Redflex or ATS lobbyist comes knocking, the council members can be heard saying, “Stop! You had me at ‘x’ million dollars” instead of, “let me consult our traffic engineering department to see if this is the best solution for our city.”



  1. NO tp 4 Me
    Posted June 27, 2009 at 9:20 pm | Permalink

    you are forgetting that over time…. the behavior will be learned by the residents in the immediate area of the camera and those that work or travel through the area. let’s see the study done after 5 years!! how long after the install was this study done? 1 year?

    • photoradarscam
      Posted June 30, 2009 at 2:52 am | Permalink

      No, you are wrong, many studies have proven this. While people may adapt to the increased time, it does NOT reduce the safety benefit of adjusting the time.

      I know you won’t bother, but here’s another study from the Texas Transportation Institute.

      The study found that improving signal visibility reduced violations 25 percent. Other changes could net between 18 and 48 percent reductions. Yet they found when the yellow signal was 1 second shorter than what the standard ITE timing formula specifies as a minimum, red light violations jumped 110%. Adding an additional second to the ITE minimum yellow yielded 53% reduction in violations, producing the greatest benefit of all the factors studied (2-6). When safety is the main concern, preventing crashes is more important than reducing violations. Yellow signal timing again proved most effective in reducing crashes. An extra second yielded a 40 percent collision reduction.

      The study also found that the vast majority of red light camera tickets are issued within the first second a light is red — in fact, the average ticket is issued when the light has been red for half a second or less. Yet right-angle crashes, which account for the majority of red-light related collisions, “with one exception, all of the right-angle crashes occurred after 5 seconds or more of red” (5-16). In other words, tickets are being issued primarily for split-second violations where collisions are not occurring.

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