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Message |
Forum: Speed, Safety, Driving and The Law Topic: Degrees of risk |
| ndp |
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Posted: Mon Mar 06, 2006 20:11
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Replies: 94
Views: 36164
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| Weight limits are set for two entirely different reasons - to protect vulnerable road infrastructure that might be damaged by excessive weights, and to keep heavy vehicles away from what are judged to be unsuitable roads. Define "unsuitable". In this context it is whatever councillors feel to be un... |
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Forum: Speed, Safety, Driving and The Law Topic: Degrees of risk |
| ndp |
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Posted: Mon Mar 06, 2006 20:06
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Replies: 94
Views: 36164
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| Of course we know that crash delta V isn't a function of free travelling speed in any realistic sense - but I thought I'd head the argument off at the pass. Of course, we also know that free travelling speed is a large factor in the pain, risk and stupidity function, i.e. the more over the limit yo... |
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Forum: Speed, Safety, Driving and The Law Topic: Non-safety reasons for setting speed limits lower than NSL? |
| ndp |
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Posted: Mon Mar 06, 2006 20:03
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Replies: 140
Views: 57619
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| ndp wrote: And of course, everyone has a different idea of acceptable risk - so we need to define what speed creates unacceptable risk so everyone knows where they stand. Who is the "we"? In my experience, the limits are set by people with no common sense or hardly any driving experience. Royal "WE... |
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Forum: Speed, Safety, Driving and The Law Topic: Non-safety reasons for setting speed limits lower than NSL? |
| ndp |
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Posted: Mon Mar 06, 2006 20:01
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Replies: 140
Views: 57619
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| How does your analysis of the impact of speed cameras in road works take into account variations in the nature of and inflows into road works? Have you read TRL595? That's the only possible starting point. We're not talking about TRL595 or the analysis of TRL... Is that a 'no' then? A convenient do... |
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Forum: Speed, Safety, Driving and The Law Topic: Degrees of risk |
| ndp |
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Posted: Mon Mar 06, 2006 19:57
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Replies: 94
Views: 36164
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| If you don't know, why do you suppose the setting of weight limits is so different than the setting of speed limits? What I don't know is the exact criteria they use. If, for example, they want a road surface to last x number of years, they'll calculate a figure based on expected volumes of heavy v... |
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Forum: Speed, Safety, Driving and The Law Topic: Degrees of risk |
| ndp |
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Posted: Sun Mar 05, 2006 21:07
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Replies: 94
Views: 36164
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| Do you know how weight limits are set? Not exactly, but I do know that a commonly-used measure for road life is the ESAL (equivalent standard axle load), calculated as (axle weight / 8.2 tons) ^ 4.2. The design life of a road surface is then expressed in ESALs. If you don't know, why do you suppose... |
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Forum: Speed, Safety, Driving and The Law Topic: Degrees of risk |
| ndp |
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Posted: Sun Mar 05, 2006 21:04
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Replies: 94
Views: 36164
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WildCat wrote: (perfectly sound comments re: risk)
Agreed - but surely where others have to face a risk posed by others they should have some say in how much risk should be posed? |
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Forum: Speed, Safety, Driving and The Law Topic: Degrees of risk |
| ndp |
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Posted: Sun Mar 05, 2006 21:01
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Replies: 94
Views: 36164
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| Of course we know that crash delta V isn't a function of free travelling speed in any realistic sense - but I thought I'd head the argument off at the pass. Of course, we also know that free travelling speed is a large factor in the pain, risk and stupidity function, i.e. the more over the limit yo... |
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Forum: Speed, Safety, Driving and The Law Topic: Degrees of risk |
| ndp |
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Posted: Sun Mar 05, 2006 20:56
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Replies: 94
Views: 36164
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| Do you know how weight limits are set? Not exactly, but I do know that a commonly-used measure for road life is the ESAL (equivalent standard axle load), calculated as (axle weight / 8.2 tons) ^ 4.2. The design life of a road surface is then expressed in ESALs. If you don't know, why do you suppose... |
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Forum: Speed, Safety, Driving and The Law Topic: Non-safety reasons for setting speed limits lower than NSL? |
| ndp |
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Posted: Sun Mar 05, 2006 20:53
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Replies: 140
Views: 57619
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| But we've been here before - surely the point of speed limits is to provide one mechanism to discourage inappropriate speed and deal with those who use speed inappropriately? Yes. But that only applies to a minority of drivers - mostly inexperienced ones. Cite? The problem is that most cases of ina... |
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Forum: Speed, Safety, Driving and The Law Topic: Non-safety reasons for setting speed limits lower than NSL? |
| ndp |
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Posted: Sun Mar 05, 2006 18:18
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Replies: 140
Views: 57619
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| It is important to remove bias or hidden agenda when evaluating effectiveness of a speed camera or SCP. Surely you agree with that? Of course. How do we propose we do that? A good start would be to stop SCPs from analysing their "own" statisics and reviewing their "own" performance. Surely even if ... |
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Forum: Speed, Safety, Driving and The Law Topic: Degrees of risk |
| ndp |
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Posted: Sun Mar 05, 2006 18:03
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Replies: 94
Views: 36164
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| Of course we know that crash delta V isn't a function of free travelling speed in any realistic sense - but I thought I'd head the argument off at the pass. Of course, we also know that free travelling speed is a large factor in the pain, risk and stupidity function, i.e. the more over the limit yo... |
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Forum: Speed, Safety, Driving and The Law Topic: Degrees of risk |
| ndp |
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Posted: Sun Mar 05, 2006 17:54
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Replies: 94
Views: 36164
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| I cannot think of another 'black and white' traffic law that is endlessly grey in practice. If there was one, I'd probably make the same suggestion. Drink driving re blood alcohol levels? Weight limits? But in neither case do the police routinely turn a blind eye to what they know to be offending i... |
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Forum: Speed, Safety, Driving and The Law Topic: Non-safety reasons for setting speed limits lower than NSL? |
| ndp |
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Posted: Sun Mar 05, 2006 17:52
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Replies: 140
Views: 57619
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| Most speed enforcement occurs where speeding is least dangerous. And you base this on what? Study this: http://www.safespeed.org.uk/rules.html We've done that one before. Why exactly would speed cameras be needed if people are obeying the limit? What purpose would it serve? Maybe the fact people pe... |
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Forum: Speed, Safety, Driving and The Law Topic: Non-safety reasons for setting speed limits lower than NSL? |
| ndp |
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Posted: Sun Mar 05, 2006 17:49
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Replies: 140
Views: 57619
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| And what do you do if a significant proportion of drivers are simply driving too fast? Too fast for what? Apologies for missing this - but it happens I answered this when Peter asked this: Too fast being that their speed presents an unacceptable risk of an accident occuring and/or that the conseque... |
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Forum: Speed, Safety, Driving and The Law Topic: Degrees of risk |
| ndp |
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Posted: Sun Mar 05, 2006 17:44
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Replies: 94
Views: 36164
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| Weight limits? Exceeding weight limits will generally result in an unacceptable level of road wear or risk of structural damage. The life expectancy of a road surface, for instance, is almost directly (inversely) related to around the fourth power of axle weight - which leaves little in the way of ... |
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Forum: Speed, Safety, Driving and The Law Topic: Non-safety reasons for setting speed limits lower than NSL? |
| ndp |
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Posted: Sat Mar 04, 2006 23:31
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Replies: 140
Views: 57619
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| As for the "engineering changes to the road", I have no problem with narrowing roads with stout iron or concrete bollards, as they have done in London. These are far scarier to perps than road humps, and many of them have lots of paint on them, showing that they creating employment in bodyshops! Th... |
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Forum: Speed, Safety, Driving and The Law Topic: Non-safety reasons for setting speed limits lower than NSL? |
| ndp |
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Posted: Sat Mar 04, 2006 23:29
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Replies: 140
Views: 57619
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| From Simonet & Wilde on risk homeostasis: . . . Quoted some time ago by "teabelly", don't have original reference - search for his post. But thats all expectation - what has actually happened? It just shows that it's a recognised behavioural phenomenon. Granted - but thats it. And it does seem ... |
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Forum: Speed, Safety, Driving and The Law Topic: Non-safety reasons for setting speed limits lower than NSL? |
| ndp |
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Posted: Sat Mar 04, 2006 23:21
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Replies: 140
Views: 57619
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| And what do you do if a significant proportion of drivers are simply driving too fast? Too fast for what? Apologies for missing this - but it happens I answered this when Peter asked this: Too fast being that their speed presents an unacceptable risk of an accident occuring and/or that the conseque... |
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Forum: Speed, Safety, Driving and The Law Topic: Non-safety reasons for setting speed limits lower than NSL? |
| ndp |
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Posted: Sat Mar 04, 2006 23:17
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Replies: 140
Views: 57619
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T2006 wrote: It is important to remove bias or hidden agenda when evaluating effectiveness of a speed camera or SCP. Surely you agree with that?
Of course.
How do we propose we do that?
Quote: I don't think sheep, goats or even squirrels have anything to do with statistical analysis.
Whoosh! |
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