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Comment by mjamesaustin | Hacker News Reader

Red light cameras increase the rate of rear ends, sometimes dramatically, as drivers unsafely brake to avoid the fine.

My understanding is that this sort of rear-end crash generally tapers off as a sufficient number of local drivers become accustomed to driving safely instead of racing to make it through a yellow light.

But even if it doesn't, it might still be a reasonable tradeoff. A higher number of minor rear-end crashes (typically between unsafe drivers) might be acceptable if it helps to reduce more t-bone crashes that are more likely to be fatal.

In Pasco county FL it didn't taper off. We just had a huge increase in collisions until they took the cameras down.

https://www.tampabay.com/opinion/editorials/red-light-camera...

Fatalities seems like a more relevant safety metric than collisions.

"IIHS research examining large U.S. cities with red light camera programs found significant reductions in citywide fatal red light crash rates (and fatal crash rates of all types) at intersections with traffic signals, including intersections that didn’t have a camera. ... Cities that discontinue their programs tend to feel the sting. The fatal crash rate was 30% higher in cities that shuttered their red light camera programs." https://www.amica.com/en/resources/auto/safety/ways-red-ligh...

But the data do indicate that the benefits of automated traffic enforcement vary widely by community. I suspect any of poor road design, reckless driving culture, or local corruption that prioritizes income over safety can lower their net utility, and some combinations of those might even make their utility net negative.

No, if it increases the rate of rear end collisions, it means that drivers are unsafely following too close to react to the driver in front of them, behind the drivers that are planning to unsafely and illegally run the red light and then changing their mind late in reaction to the camera.

Surgery increases your odds of dying during surgery. It also saves far more lives than it costs.

Unless you've seen data that says otherwise, I think this is the same.

For that to be true, how fast must they have been going through the yellow?

It just requires that the driver behind them was unsafely and illegally failing to maintain a safe following distance (and/or failing to pay attention to the car in front of them.)

That's true of all rear-ends, but for the ones that are influenced by the presence of a red light camera, it must also mean that the crash wouldn't have happened without a camera-induced behaviour shift in the leading car. So it requires not only an unsafe following car, but also the lead car going too fast towards a yellow and then braking suddenly, upon remembering that they'll lose money for going through a red light. Still the fault of the car in the rear of course, but if the car in front is driving reasonably in the first place, then the red light camera won't have any effect. The ones who get rear-ended are the ones who were going to anyway, camera or not.

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