from the not-always dept
After digging in, it looks like some of this may just be bad reporting by Scientific American's Cynthia Graber. First, she focuses the article on red light cameras, but the actual study she discusses was for speed cameras. I'm surprised that Scientific American would mix up the two, since they're clearly different. Second, as some people pointed out in the comments to Graber's story, the study happened over a two year period during which unemployment in Barcelona shot up drastically, potentially leading to fewer cars on the road, especially during rush hour periods when accidents are most likely. In other words, while this might be some evidence in support of speed cameras, at best, it shows a correlation, and the causal factor may be something entirely different, such as the amount of cars on the road.