SoylentNews is people
SoylentNews
Speed cameras have been the focus of motorists' anger and frustration for years, although we are told repeatedly that they are an effective means of reducing death and injury on the roads. But is this really the case?
Whether speed cameras actually do save lives seems an easy assertion to test: measure the numbers of casualties at a site over a period, say two years; introduce a speed camera; re-measure the number of casualties over an equal period, and any reduction is due to the camera. But it's not really that simple. Many other factors are at play that might make cameras appear to be more effective than they really are. And these factors are often ignored when evaluating the performance of speed cameras at improving road safety.
Do speed cameras actually save lives?
[...] In road safety data, there is a general tendency for collision incidents at a site to reduce anyway following a short-term rise in their number, without any treatment (such as a speed camera) being applied. In statistics, this is known as regression-to-the-mean (or RTM). We also know that the long-term trend in collisions has generally been downward due to factors such as improved vehicle safety and better driver education[PDF].
So if we observe a reduction in casualties at a site following the installation of a camera, we need to ask how much of this reduction would have happened anyway (the RTM effect)? How much is due to general trends in road safety? And how much can we actually attribute to the camera itself?
[...] To make matters worse, half of the UK's fixed speed cameras may not even be turned on. So the situation is far from simple.
Methods to accurately account for RTM and trend often require knowledge of advanced statistics which may not always be available within a road safety team, and so it is likely that these confounding factors are not being considered consistently across the country.
[...] So, do speed cameras save lives? The answer is almost certainly yes, but probably not always to the extent that people are led to believe.
https://theconversation.com/do-speed-cameras-really-save-lives-87701
(Score: 0) by Anonymous Coward on Tuesday November 21 2017, @09:10PM (2 children)
Unless the yellow lights had previously been extended in an effort to prevent t-bone crashes and the final length is reasonable, there's no problem with that.
Times get cut on yellow in order to increase throughput on the intersection. During a yellow light you're not supposed to enter the intersection unless you can't safely stop. It exists because it takes a moment for somebody to register a change in the light and going to yellow is less problematic than going to red in all directions while the traffic clears the intersection. Because there's not supposed to be any vehicles in the intersection when the light is yellow, it makes for a period that's wasted in terms of traffic movement, so it gets shortened when possible.
(Score: 0) by Anonymous Coward on Wednesday November 22 2017, @08:29AM (1 child)
That's not even half of it. Even if you could register the change instantly, you'd need Star Trek level brakes ("Full stop, Mr. Zulu") to go from 45 to 0 when you do register the change one foot before entering the intersection.
And even if you did have Star Trek level brakes, just imagine the number of cars rear ending you because they don't have Star Trek level brakes.
(Score: 0) by Anonymous Coward on Wednesday November 22 2017, @03:42PM
http://memory-alpha.wikia.com/wiki/Hikaru_Sulu [wikia.com]