PDA

View Full Version : Smeed's Law


ORAC
10th Dec 2006, 10:57
From an essay by Freeman Dyson concerning OR in Bomber Command (http://www.technologyreview.com/search.aspx?s=Freeman+Dyson&Search.x=34&Search.y=6)in WWII:

.......Smeed also had a fatalistic view of traffic accidents. He collected statistics on traffic deaths from many countries, all the way back to the invention of the automobile. He found that under an enormous range of conditions, the number of deaths in a country per year is given by a simple formula: number of deaths equals .0003 times the two-thirds power of the number of people times the one-third power of the number of cars.

This formula is known as Smeed's Law. He published it in 1949, and it is still valid 57 years later. It is, of course, not exact, but it holds within a factor of two for almost all countries at almost all times.

It is remarkable that the number of deaths does not depend strongly on the size of the country, the quality of the roads, the rules and regulations governing traffic, or the safety equipment installed in cars.

Smeed interpreted his law as a law of human nature. The number of deaths is determined mainly by psychological factors that are independent of material circumstances.

People will drive recklessly until the number of deaths reaches the maximum they can tolerate. When the number exceeds that limit, they drive more carefully. Smeed's Law merely defines the number of deaths that we find psychologically tolerable.

tony draper
10th Dec 2006, 11:06
Watched one of those Nation on Film progs a couple of weeks back, covering the early days of motoring ie twenties to thirties the number of cars on the road was tiny compared to nowadays yet there was a absolute slaughter due to accidents involving motor vehicles,If I recal correctly the year 1934/35 over 7000 deaths,this forced the government to bring in some rules ie Driving tests trafic lights,as I understand it there had been no rules regarding driving to that point.
:uhoh:

seacue
10th Dec 2006, 11:21
While statistics I find seem to disprove the point, I think 1937 was a high point in deaths per mile-traveled or number-of-cars or something in the USA. Many on the cars were pre-Depression and getting old and roads were also pre-Depression - but people had a little more cash and could afford to drive more.

Being considerably older than FSL Draper, I recall as a kid returning from the countryside of a Sunday evening and passing accidents with victims laid out beside the road. That would have been in the 1937-8 time frame.

tony draper
10th Dec 2006, 11:29
Another thing, slightly off topic though ,one recals reading with astonishment that there were no proper roads as such in the USA right up to the outbreak first world war,ie 1917 in their case,they did not have a General Wade or the Scots to deal with on a regular basis I suppose.
:rolleyes:

G-CPTN
10th Dec 2006, 11:38
What about the Romans?
Didn't they have an trans-atlantic expeditionary force?


After all the A1 was built by the Romans (as also was the A5 I believe).

http://upload.wikimedia.org/wikipedia/commons/6/60/Romanbritain.jpg

tony draper
10th Dec 2006, 11:51
Yer we was all roaded up pretty early,some of those Roman roads have just been resurfaced a couple of times since and are still working.
Just as well they was built before those feckin Atrebanties started running the bloody country.
:rolleyes:

Farmer 1
10th Dec 2006, 12:12
Are you sure you're not thinking of Cole's Law?

G-CPTN
10th Dec 2006, 12:14
Nah! coleslaw is more like shredded cabbage.
Ani fule kno that.

Aaaaaaaaaaaaaaaargh!
10th Dec 2006, 15:06
What Roman Atlas? They had a settlement in present day Ambleside called Galava, so how come there's nothing in the Lake District?

TheDesertFerret
10th Dec 2006, 15:19
Aaaaaaaaaaaaaaaargh!

I believe the cartographer was miffed because the mayor of Galava had been merrily shagging his neice without coffing up the dowry of "a lame goat", hence the omission.

Incidentally - road safety in the UK is an unspoken success, 3,000 deaths per yer, less than twenty years ago even though traffic has trebled.

All governments are obliged to not bang on about this though as it would be counter-productive - we need to keep people scared of the road to promote safety awareness - suggesting it is safe won't help.

tony draper
10th Dec 2006, 16:29
They should never have abolished the law that obliged all motor vehicles to have a chap walking in front of with a red flag, horses seldom collide with each other and their exhausts are good for the rhubarb.
:rolleyes:

Loose rivets
10th Dec 2006, 17:24
twenties to thirties the number of cars on the road was tiny compared to nowadays yet there was a absolute slaughter due to accidents involving motor vehicles,
:uhoh:



s'funny, one was thinking about that the other day.

I think it had a lot to do with the luckless pedestrian's brains not being able to calculate the speed of the hardware bowling down on them. Now we often see stuff heading our way at frightening speeds.

flowman
10th Dec 2006, 17:30
Incidentally - road safety in the UK is an unspoken success, 3,000 deaths per yer, less than twenty years ago even though traffic has trebled.

It's probably precisely because traffic has trebled that road deaths have gone down. It's difficult to do much damage when you are shuffling along at 1kt or less most of the time. :*

tony draper
10th Dec 2006, 19:01
If they could figure out a way of taxing pedestrian for the use of the pavement they would prolly look after them better.
:uhoh:

Capt.KAOS
10th Dec 2006, 19:20
People will drive recklessly until the number of deaths reaches the maximum they can tolerate. When the number exceeds that limit, they drive more carefully. Smeed's Law merely defines the number of deaths that we find psychologically tolerable.Wherez the factor that modern cars are much safer these days in the equation?

con-pilot
10th Dec 2006, 19:35
Another thing, slightly off topic though ,one recals reading with astonishment that there were no proper roads as such in the USA right up to the outbreak first world war,ie 1917 in their case,they did not have a General Wade or the Scots to deal with on a regular basis I suppose.
:rolleyes:

Too true Mr. D., not only did the native population of the Americas never conceive the concept of the wheel, they didn't adopt the use of the wheels for many generation after the wheel was introduced to the Americas by the invading European hordes. (Well except for those pesky Romans of the past, we got the pasta generation.)

When I was 15 I asked my great-grandmother why 'her' people never invented or used the wheel.

She looked at me with her old wise eyes, full of wisdom and many memories and said, "Great-grandson, it is not 'my' people, you are my blood, the blood of 'our' people and the blood of all of those who has passed before us."

Then she hit me in the head with a big wooden spoon and said, "Now don't ask any more damn fool questions!"

I didn't. :\

tony draper
10th Dec 2006, 19:50
Oddly enough the Aztecs did know of the wheel, childrens toys have been found that have wheels,suppose their bailywick was a bit lumpy with more up and down than flat for the wheel to be of much use to em.
:cool:

stagger
10th Dec 2006, 22:52
Approximately...

UK population 60,000,000
UK cars 30,000,000

Smeeds law predicts 14,287 annual road deaths.

Actual annual road deaths around 3,000.

So Smeed's prediction is wrong by around a factor of 5 - i.e. actual deaths are about 80% less than predicted.

con-pilot
10th Dec 2006, 22:56
Actual annual road deaths around 3,000.

Hmm, maybe you are not trying hard enough. :ooh:

ORAC
11th Dec 2006, 17:46
Wikipedia - Smeed's Law (http://en.wikipedia.org/wiki/Smeed's_law) with some references. Didn't take someone long to put in the link to the article... :)

Rainboe
11th Dec 2006, 20:20
I think Smeeds Law is a very vague, blunbt instrument that is not borne out in reality. What I think is amazing is the low number of UK road fatalities compared to the startlingly higher figures for similar European countries, France, Spain, even Portugal. It is either better driving education (which I can't believe) or the fact that the UK road congestion is so severe nobody can speed so dangerously anyway! The discrepancy is amazing. It used to be double the fatalities in the UK- 20/day instead of less than 10 now.

G-CPTN
11th Dec 2006, 21:23
I'm still astounded by the number of collisions reported daily on the traffic news (major roads only). Why don't drivers just AVOID each other? Why must vehicles on motorways crash into each other? It can't be THAT difficult to keep away from the vehicle in front of you, can it?

Of course, silly young men will still drive at excessive speeds along minor roads and collide with oncoming vehicles or through hedges into trees, but these represent a self-eliminating risk to others (albeit involving injuries or deaths to the unfortunate few who get in their way). :ugh:

But WHY do other motorists (including truck drivers) crash into each other?

tony draper
11th Dec 2006, 22:28
We drive on the correct side of the road Mr Rainboe.:rolleyes:

Aaaaaaaaaaaaaaaargh!
12th Dec 2006, 00:21
What I think is amazing is the low number of UK road fatalities compared to the startlingly higher figures for similar European countries, France, Spain, even PortugalI think it's simply empirical proof that SPEED CAMERAS SAVE LIVES!!! :ok:

TheDesertFerret
12th Dec 2006, 00:26
We've always had an excellent road safety record - it was so way before speed cameras.

Now we've got most drivers driving safely now we can concentrate on stopping them driving like ar$eh*les. Subtle distinction I know.