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The objective evidence shows an increase in rear-end crashes but a reduction in injury and fatal crashes, offering a net overall benefit. Council et al., 2005

The objective evidence shows an increase in rear-end crashes but a reduction in injury and fatal crashes, offering a net overall benefit. Council et al., 2005 -- https://www.fhwa.dot.gov/publications/research/safety/05048/05048.pdf https://www.fhwa.dot.gov/publications/research/safety/05048/...

giantg2 7mo ago
This states that there are many variables they were not able to control for, such as the yellow light timing, as I previously mentioned. Warning signs were another major factor. There doesn't appear to be enough investigation into the protected left issue. This is pretty damning, in my opinion. AKA we did some cheap analysis on a small dataset, without confidence or effect size, and just agree with the people running the programs. "The intent of the multivariate regression analysis was to confirm the direction of the effect, not to establish effects with statistical significance or to assess the size of the effect. To undertake analyses for these purer purposes would have required a substantially larger database, much more precision in the estimate of economic effect at each site, and more accurate specification and measurement of the independent variables. For the purposes of this current investigation, it suffices that both the univariate and multivariate analyses are reasonably in accord with the perceptions that are commonly held by those involved in red-light-camera programs."
LorenPechtel 7mo ago
There's a regression to the mean issue at work. Sometimes an intersection simply has bad luck, draws more accidents than anything about it would cause. Put a camera there, you'll see an "improvement".
- SecretDreams 7mo ago
  One might argue the intersection itself is the problem and should be redesigned, as well as adjoining roadways feeding into the offending intersection.
  - LorenPechtel 7mo ago
    If it's consistently high something needs fixing. But accidents are random, there will always be some intersections that by pure chance have more accidents. Put cameras on those, presto, cameras "work".
    - deleted 7mo ago
      [deleted]
    - SecretDreams 7mo ago
      Some intersections having more accidents by pure chance is kind of an oxymoron, imo.
      - LorenPechtel 7mo ago
        What's an oxymoron about it? Let's make a hypothetical city with 10 intersections, all absolutely identical. Watch until you have seen 20 accidents. Do you really think there will be exactly 2 accidents per intersection?? Select the intersection that gets the most accidents, declare it dangerous. Case A: stick a camera on it. Case B: do nothing. Watch another 20 accidents. In both cases you expect to see fewer accidents at the intersection as the original number was just chance. But if you're trying to prove cameras work...

giantg2 7mo ago

This states that there are many variables they were not able to control for, such as the yellow light timing, as I previously mentioned. Warning signs were another major factor. There doesn't appear to be enough investigation into the protected left issue. This is pretty damning, in my opinion. AKA we did some cheap analysis on a small dataset, without confidence or effect size, and just agree with the people running the programs. "The intent of the multivariate regression analysis was to confirm the direction of the effect, not to establish effects with statistical significance or to assess the size of the effect. To undertake analyses for these purer purposes would have required a substantially larger database, much more precision in the estimate of economic effect at each site, and more accurate specification and measurement of the independent variables. For the purposes of this current investigation, it suffices that both the univariate and multivariate analyses are reasonably in accord with the perceptions that are commonly held by those involved in red-light-camera programs."

LorenPechtel 7mo ago

There's a regression to the mean issue at work. Sometimes an intersection simply has bad luck, draws more accidents than anything about it would cause. Put a camera there, you'll see an "improvement".

SecretDreams 7mo ago
One might argue the intersection itself is the problem and should be redesigned, as well as adjoining roadways feeding into the offending intersection.
- LorenPechtel 7mo ago
  If it's consistently high something needs fixing. But accidents are random, there will always be some intersections that by pure chance have more accidents. Put cameras on those, presto, cameras "work".
  - deleted 7mo ago
    [deleted]
  - SecretDreams 7mo ago
    Some intersections having more accidents by pure chance is kind of an oxymoron, imo.
    - LorenPechtel 7mo ago
      What's an oxymoron about it? Let's make a hypothetical city with 10 intersections, all absolutely identical. Watch until you have seen 20 accidents. Do you really think there will be exactly 2 accidents per intersection?? Select the intersection that gets the most accidents, declare it dangerous. Case A: stick a camera on it. Case B: do nothing. Watch another 20 accidents. In both cases you expect to see fewer accidents at the intersection as the original number was just chance. But if you're trying to prove cameras work...