Friday, September 3, 2010

Anti Speed Camera Arguments - #2 - Distraction

Cast your mind back, dear reader, way back to yesterday. You'll recall I'm trying to debunk the anti-speed camera arguments put forward by 'Safe Speed'. I started by addressing the supposed correlation between road death trends and the introduction of speed cameras.
Today I'll look at the idea that speed cameras distract drivers. What case do Safe Speed make?

"Accidents happen when people make mistakes. About 75% of those mistakes are carelessness or inattention." 

Depends what you mean by 'accident'. Most 'accidents' are not due to factors outside the control of drivers, and could and should be avoided. Where do they get 75% from? In terms of inattention, 2003 figures attribute 'driver/rider distracted as a factor in 5.5% of accidents. Does 'Going too fast for circumstances' count as carelessness? What about 'Vision Obscured' - if your vision is obscured you should expect the unexpected and proceed carefully, right? You'll notice I give proper sources and citations for my data. That's because I'm a scientist and I don't expect people to take figures on trust. Unlike 'Safe Speed'.

"About 5% of those mistakes involve excessive speed."
Not according to my previously cited government figures. They say 'Going too fast for circumstances' is a factor in 8.4% of crashes and 'Suspected contravention of statutory speed limit' is a factor in 2.2%. Of course, Government stats are only based on STATS19 forms compiled by the police. Maybe Safe Speed have been able to find a more authoritative source, or do their own analysis of thousands of crashes?
Bear in mind that almost all crashes are less severe and many can be avoided if drivers are going slower.  The slower you go the more time you have to react, and the less severe the impact - that's because of Newton's laws (science again you see). Also, the amount of time the police have to analyse crashes is very limited. Many people lie about or at least underestimate how fast they were driving after a crash, and unless the police can gather any evidence to the contrary, excessive speed may not be recorded as a cause. Therefore it seems likely that there is under-reporting of speed as a factor in crashes.

"speed cameras ... alter the things that drivers pay attention to. Too many drivers now spend far too much time considering ... speed limit compliance and the risk of enforcement. Sometimes ... they are spending precious milliseconds worrying about numerical speed while an unseen dangerous situation is developing ahead."
 Sorry, but this is a stretch. Driving is always a multitasking activity. You need to systematically scan the road ahead and to the side, your mirrors and your instrument panel on a continuous basis, and increase or reduce your speed according to hazards that you observe. Some people, incredibly, can listen to the radio as well, or conduct a conversation with a passenger! You need to take notice of road signs and comply with them, You need to plan manoeuvres. It's essential to be setting your speed correctly. If you cannot monitor and control your speed whilst driving, you probably shouldn't be driving. Are we saying that drivers who are incapable of doing that would be safer if they worried less about their speed? Are they in fact capable of setting their speed correctly without the guidance of speed limits or the threat of enforcement?
Now, I'm not going to say that speed cameras are never a distraction. They are. But the question is whether the momentary distraction of seeing a speed camera and checking your speed represents a greater danger than allowing higher average speeds (recall from my citation yesterday that cameras do lower average speeds).
Let's look at some other factors that may mitigate the distraction. 
1. Most cameras are sited on busy roads. What tends to happen most of the time is you get a moving line of traffic, and the line moves at the speed of the slowest vehicle. That speed is controlled by the camera, so in actual fact drivers don't have to worry about their speed. 
2. Many journeys are along familiar roads. Therefore, drivers know both the speed limits and the location of cameras, so they are less likely to be distracted by them as they are on unfamiliar roads.





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