Talk:Smeed's law
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[edit] Edits 13 June 2006
"to the cube root of car ownership" changed to "to motor vehicle registrations and population". "and appears still to hold today" deleted. "Smeed's law raises the conclusion that "accident statistics do not measure safety or danger; as traffic increases, the death toll is contained, and sometimes reduced, by behaviour that avoids danger rather than removing it." (Adams, 1995)Thus even modern, "safe" vehicles driven in countries with low rates of car ownership generate a death rate that can be predicted by Smeed's law. Neither safe vehicles nor safe roads can reduce the death rate, but rather people adjusting to the dangers of motor vehicles." deleted.
"However, the validity of Smeed's Law has also been disputed by several other authors (for example Andreassen 1985, Oppe 1991, Ammen & Naji 2000)." added.
See below for complete justification of these changes:
Smeed's 'Law' does not relate "casualties" to "car ownership". First, it specifically concerns deaths; whereas casualties can refer to injuries and property damage only accidents as well. Second, the 'Law' also relates deaths to population.
Also, Smeed's 'Law' does not 'appear to hold today'; there are a number of academic articles which dispute said 'Law' (e.g. Andreassen 1985 Engineering & Control pp 547-549, Oppe 1991 Accident Analysis & Prevention 23(5) pp 401-412, Ameen & Naji 2000 Accident Analysis & Prevention 33 pp 547-561); and if one is to examine current data for any state in the U.S. one its innaccuracy is apparent. For example; according to Smeed's 'Law'; there should have been around 4700 motor vehicle deaths in the state of New York (Registered vehicle data from NYS DMV[1], population data from BEA[2]) -- however, there were only 1493. When the formula is applied to other years of the past decade, an average difference between the model formula results and the actual number of deaths of 3000 is arrived at.
Finally, the statement "Neither safe vehicles nor safe roads can reduce the death rate, but rather people adjusting to the dangers of motor vehicles." is highly debatable (and is likely a misinterpretation of Smeed's hypothesis). In Smeed's famous article, he states that "It is probable that as the population accident rate becomes higher the urge to do something about it becomes greater, and that something is in fact done. In addition, as the number of motor vehicles increases, which is in practice as time goes on; people are growing up and becoming more used to dealing with the situations which motor traffic causes." (Smeed 1949 Journal of the Royal Statistical Society 112(1) pp. 1-34 -- italics mine). This suggests that factors other than people driving more safely may very well also lower accident rates.
[edit] Link removed 26 Dec 2005
- Smeed and beyond, sceptical of the Smeed Law
This appears to be a monograph by somoene with no recognised expertise in the field of statistical analysis or road safety policy. Please name the reputable sources which have presented this argument. - Just zis Guy, you know? [T]/[C] AfD? 14:01, 26 December 2005 (UTC)
- I have reviewed the link. While the authorship is not clear, and the link has a barrow to push, there seems no reason not to include the link. Why should safespeed.org.uk not be reputable? I have reincluded it.--A Y Arktos 21:22, 3 January 2006 (UTC)
- Because they have made many claims which are clearly bunk, none of which have eben peer-reviewed, they also assert that many reliable sources (e.g. the Transport Research Laboratory) are "flawed" or "fraduluent". The site has no academic credibility, and a history of writing "research" from the conclusions backwards, with proof by assertion being their major tool. - Just zis Guy, you know? [T]/[C] AfD? 22:00, 3 January 2006 (UTC)
- I am certainly very wary of the barrow about speed cameras and thus am happy to concur with your concerns.--A Y Arktos 22:09, 3 January 2006 (UTC)
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- I have removed the POV discrediting of the source, and left the fact, I hope. Rich Farmbrough. 12:03, 18 February 2006 (UTC)
Here's the text:
It has been suggested that improvements in safety of roads and cars have contributed to the reduction in road fatalities and that in Great Britain from 1966, although the Smeed relationship predicted fatalities would continue to rise, real road deaths have fallen quite reliably, such that by 2000, the Smeed prediction was about 4 times too high. The organisation putting forward this data was supporting an argument that "one third of roads fatalities are due to speed cameras (and the policies that support them)."[3]
The problem here is that the Smeed law does not state that fatalities would continue to rise, quite the opposite - the continuing rise in numbers of vehicles means that Smeed predicts the numbers will fall. Also, the source making the claim is so far short of reliable as to make the claim's inclusion problematic for me. The "one in three" argument advanced by that group is complete bollocks for a number of reasons, not least the fact that the purported loss of trend applies solely to motorcyclists, and is based on comparing fatality figures for individual years (which is invalid due to stochastic noise) and also because there was a change in the reporting mechanism, cited in the source of the figures, which makes the comparison invalid. No claim made by this source has ever been submitted for publication in a peer-reviewed jounal. I am certian there are reputable traffic safety professionals who have spoken out against the Smeed law, let's see if we can't find one of them instead of someone blatantly pushing an agenda. Just zis Guy, you know? [T]/[C] 
13:38, 18 February 2006 (UTC)
[edit] Formula
ISTM the formula is cube root, not inverse square. Please revrt if I'm going mad. Rich Farmbrough. 12:03, 18 February 2006 (UTC)s
[edit] Confused
I have to say that in trying to avoid pushing a point of view, editors have made Sneed's point of view incomprehensible. Can we state clearly what Sneed or people who cite his law are getting at, and then point out that other people challenge the validity of his statistics? Nareek 21:10, 1 September 2006 (UTC)
