Slashdot Mirror
Study: Red Light Cameras Don't Improve Safety
An anonymous reader writes: Ars Technica summaries a study by the Chicago Tribune (paywalled) that found red light cameras do not improve driver safety. "[W]hile right angle crash incidents have been reduced, rear-end crashes that resulted in injuries went up 22 percent." Chicago officials recently claimed that the cameras led to a 47% reduction "T-bone" injury crashes, using that statistic as evidence that the program is worthwhile. But the study's authors, who "accounted for declining accident rates in recent years as well as other confounding factors, found cameras reduced right-angle crashes that caused injuries by just 15 percent."
They also noted that the city chose to install many cameras at intersections where crashes were rare to begin with. Chicago has raised roughly $500 million from red light camera tickets since 2002. "[O]fficials recently admitted to the city inspector general that they had quietly dropped the threshold for what constitutes a red light camera ticket, allowing the tickets even when cameras showed a yellow light time just under the three-second federal minimum standard. That shift earlier this year snared 77,000 more drivers and $7.7 million in ticket revenue before the city agreed to change the threshold back.
They also noted that the city chose to install many cameras at intersections where crashes were rare to begin with. Chicago has raised roughly $500 million from red light camera tickets since 2002. "[O]fficials recently admitted to the city inspector general that they had quietly dropped the threshold for what constitutes a red light camera ticket, allowing the tickets even when cameras showed a yellow light time just under the three-second federal minimum standard. That shift earlier this year snared 77,000 more drivers and $7.7 million in ticket revenue before the city agreed to change the threshold back.
Ticket: I have to pay.
Rear ended: His insurance will pay for it.
The choice is obvious. Fuck safety.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
If they really wanted to make money, they should have put the Red Light Cameras in the Red Light District.
"Transparent" is a shit show that trades on every stereotype going. A man in drag is NOT a transsexual.
If you are choosing between "slamming your brakes at the last second" or "running a red light" then you were driving unsafely.***
There is a significant correlation between installing the cameras and shortening the yellow. At the same time, even if the yellow was too short even before the cameras were installed, they increase the risk of accidents since people will no longer be willing to run the very beginning of the red (before traffic the other way starts moving).
"[W]hile right angle crash incidents have been reduced, rear-end crashes that resulted in injuries went up 22 percent." Chicago officials recently claimed that the cameras led to a 47% reduction "T-bone" injury crashes, using that statistic as evidence that the program is worthwhile. But the study's authors, who "accounted for declining accident rates in recent years as well as other confounding factors, found cameras reduced right-angle crashes that caused injuries by just 15 percent."
So the article says rear-end went up 22% and T-bone went down 47%. You have to be suspicious whenever you see a news article that says x went down by y%.
per cent of what? What were the base numbers?
Here's some example situations to show why I say that.
suppose before red light camera we had 100 rear-end crashes and 10,000 t-bone crashes at the intersection (all with injuries)
suppose after red light, we have 122 rear-end crashes and 5,300 t-bone crashes. That's 22% rear-end up and 47% t-bone down
But, the total number of injuries dropped 4,678. That's good isn't it? Redlight cameras must be great!
Or, suppose this:
before red-light camera, 10,000 rear-end and 100 t-bone w/injury
after red-light camera: 12,200 rear-end and 53 t-bone w/injury again, 22% increase in rear-end and 46% decrease in t-bone.
so we had an increase of 2,153 injuries total. Oh my, red-light cameras are killers, aren't they?
I used a wide disparity in the numbers to make my point: you cannot make a useful comparison between percent changes in numbers of two different measurements without knowing the base numbers. That is covered in your freshman "Lying with Statistics 101" class.
So, I read the article in the Tribune (it's free if you give them your email address and live out-of-zone)
If you read the Tribune article (and the accompanied "How the Red Light Camera Study was Done" you may come away with a quite different view than the slashdot summary or the ArsTechnica summary. The Tribune article is not as ridiculous as the slashdot summary.
The article does indeed have some raw numbers:
Quoted from the Tribune:
"In raw numbers at the 90 intersections included in the study, the researchers concluded the cameras prevented as many as 76 right-angle crashes and caused about 54 more rear-end injury crashes. The study said that without the red light cameras about 501 angle crashes would have occurred and only 425 were reported. It also said that there were 296 rear-end injury crashes, and there would have been only 242 had the cameras never been installed."
I've been driving for a few decades and have seen many serious injuries and fatalities, but not a single serious injury or corpse in a rear-end crash.
If you give me a choice between trading 76 t-bones crashes for 54 rear-end crashes, I'd take those numbers. As many other posters have observed, t-bone crashes are much more likely to result in serious injuries and deaths than rear-enders.
The two Tribune articles also covers some of the crookedness associated with Chicago's use of the cameras. They are both a good read and covers a lot of why you should be careful about these numbers and problems associated with the data.
This isn't exactly news, as various cities have been caught illegally reducing the yellow light durations below the federally mandated minimums for the purpose of fund generatiou by entrapment through red light cams.
There have also been several other studies that show that the red light cams actually increase accident rates.
So people who drive that road know they have to stop fast on a yellow even if they can't do it safely.
Ticket: I have to pay.
Rear ended: His insurance will pay for it.
The choice is obvious. Fuck safety.
I think both of you don't understand what it means to stop safely. Hint: It NEVER involves someone behind you. Stopping safely means you pull up before the light and don't end up stopped in the middle of an intersection. You can't stop safely at yellow if it switches to yellow and you're 2m from the intersection doing 40, you simply will end up at the very least in the intersection. But there is absolutely no reason why you can't try if you have the stopping distance.
If at any point you're rear ended (doesn't matter if there's a 40 year old truck behind you, and you're driving a Lotus Super 7 with seemingly unlimited grip and a 2m stopping distance), the person who is behind you was driving unsafely all along.
No one is fucking safety, at the worst you're calling out the douchbag tailgater on his shithouse driving by hitting him in the insurance.