Speed kills? - A statistical analysis
Discussion
Numbers can be very helpful in establishing the truth about something. Below is a sketched analysis of how much a speeding driver puts other people at risk; it can be helpful if we actually understand the facts about which there is so much prejudice and pontificating. Any refinement of my numerical estimates or other parts of the analysis would be welcome.
The justification for speed limits (and for punishment when they are violated) rests on statistics. In this way speed limits are a rare social injunction. In societies free from tyranny, almost all punishments are the result of actual harm done to another person or his/her property. We normally do not punish a man for the harm to another person that he potentially could do - by lifting a breadknife, for example - but we make an exception for speeding. As the worst outcome of misuse of a breadknife is the same as that of misuse of an automobile, the only justfication for penalising speeding on the basis of its potentiality must be the probability of serious harm.
I have tried to assess what that probability really is.
In the UK in recent times approximately 3500 people per year have died in road traffic accidents. Let us say that that amounts to ten deaths per day. It is now generally agreed that no more than five percent of those deaths are the result of a driver's exceeding the speed limit, so that means one death every other day is the result of someone's exceeding the speed limit.
In as many as forty percent of those accidents, however, the speeder is under the influence of drink or drugs, and presumably incapable of respecting either rules or driving standards. Thus the frequency of fatalities caused by drivers who were consciously exceeding the speed limit is no more than once every three days.
Next we should adjust our fatality rate to account for and deduct those people whose speeding has caused their own death. If someone chooses to do something that may be risky, that is surely his/her business and not the state's. Anti-motoring groups will sometimes interject here that even a person taking only his own life puts emergency services personnel at risk, and that this is an indefensible burden on society. That argument is a silly one, because if we accepted it we would ban sailing, horse riding, cycling, scout hikes and DIY.
My guess is that at least one-third of deaths stemming from speeding are those of the speeders themselves. Thus we might estimate that one person every four-and-one-half days has died as a result of someone else's conscious act of driving over the speed limit.
This brings us to the frequency of speeding itself - how often does this punishable act occur?
My guess is that something like ten million people drive each day, and on average they drive twice a day, which yields twenty million trips. Last year the UK Government reported that more than half of all cars were observed driving over the speed limit. This means that ten million trips per day involve speeding, according to my estimate.
The thing is, a driver who is speeding is not committing a single continuous violation. Rather, he or she is committing a series, probably an extensive series, of discrete violations. If the determinant is the number of times that the speeder is putting another person at risk (and it must be something like that), and we assume as the law presumes that speeding itself creates that risk, then every junction, turning or driveway that the speeder passes and every car that he/she overtakes or encounters must be another risk-creating violation. (Indeed, a series of Gatso's have totted some people up within a mile.) Therefore the speeding driver will usually commit numerous separate violations on a single trip. A very conservative estimate would be fifty violations per trip - the actual number could be in the hundreds.
Fifty violations per trip, ten million speeders' trips per day: that's five hundred million speeding violations per day, five hundred million times daily that drivers have created what the Government deems unacceptable risks, which acts are subject to severe punishment.
If once every four-an-one-half days there is a fatality that has resulted from another driver's consciously violating the speed limit, and there are five hundred million risk-creating speeding violations daily, then speeding creates a LESS-THAN-ONE-IN-TWO-BILLION likelihood of causing a fatality.
The above ignores the substantial proportion of fatal accidents that are caused by (usually young, I am sorry to say) idiots that shouldn't allowed to drive a nail, much less an automobile.
Assuming that these numbers are in the right ballpark, they lead me to conclude that a person who focuses on his or her driving and takes it seriously may be increasing risk to others by speeding, but that incremental increase is truly infinitesimal.
Any thoughts on the analysis?
The justification for speed limits (and for punishment when they are violated) rests on statistics. In this way speed limits are a rare social injunction. In societies free from tyranny, almost all punishments are the result of actual harm done to another person or his/her property. We normally do not punish a man for the harm to another person that he potentially could do - by lifting a breadknife, for example - but we make an exception for speeding. As the worst outcome of misuse of a breadknife is the same as that of misuse of an automobile, the only justfication for penalising speeding on the basis of its potentiality must be the probability of serious harm.
I have tried to assess what that probability really is.
In the UK in recent times approximately 3500 people per year have died in road traffic accidents. Let us say that that amounts to ten deaths per day. It is now generally agreed that no more than five percent of those deaths are the result of a driver's exceeding the speed limit, so that means one death every other day is the result of someone's exceeding the speed limit.
In as many as forty percent of those accidents, however, the speeder is under the influence of drink or drugs, and presumably incapable of respecting either rules or driving standards. Thus the frequency of fatalities caused by drivers who were consciously exceeding the speed limit is no more than once every three days.
Next we should adjust our fatality rate to account for and deduct those people whose speeding has caused their own death. If someone chooses to do something that may be risky, that is surely his/her business and not the state's. Anti-motoring groups will sometimes interject here that even a person taking only his own life puts emergency services personnel at risk, and that this is an indefensible burden on society. That argument is a silly one, because if we accepted it we would ban sailing, horse riding, cycling, scout hikes and DIY.
My guess is that at least one-third of deaths stemming from speeding are those of the speeders themselves. Thus we might estimate that one person every four-and-one-half days has died as a result of someone else's conscious act of driving over the speed limit.
This brings us to the frequency of speeding itself - how often does this punishable act occur?
My guess is that something like ten million people drive each day, and on average they drive twice a day, which yields twenty million trips. Last year the UK Government reported that more than half of all cars were observed driving over the speed limit. This means that ten million trips per day involve speeding, according to my estimate.
The thing is, a driver who is speeding is not committing a single continuous violation. Rather, he or she is committing a series, probably an extensive series, of discrete violations. If the determinant is the number of times that the speeder is putting another person at risk (and it must be something like that), and we assume as the law presumes that speeding itself creates that risk, then every junction, turning or driveway that the speeder passes and every car that he/she overtakes or encounters must be another risk-creating violation. (Indeed, a series of Gatso's have totted some people up within a mile.) Therefore the speeding driver will usually commit numerous separate violations on a single trip. A very conservative estimate would be fifty violations per trip - the actual number could be in the hundreds.
Fifty violations per trip, ten million speeders' trips per day: that's five hundred million speeding violations per day, five hundred million times daily that drivers have created what the Government deems unacceptable risks, which acts are subject to severe punishment.
If once every four-an-one-half days there is a fatality that has resulted from another driver's consciously violating the speed limit, and there are five hundred million risk-creating speeding violations daily, then speeding creates a LESS-THAN-ONE-IN-TWO-BILLION likelihood of causing a fatality.
The above ignores the substantial proportion of fatal accidents that are caused by (usually young, I am sorry to say) idiots that shouldn't allowed to drive a nail, much less an automobile.
Assuming that these numbers are in the right ballpark, they lead me to conclude that a person who focuses on his or her driving and takes it seriously may be increasing risk to others by speeding, but that incremental increase is truly infinitesimal.
Any thoughts on the analysis?
possibly
have you seen
www.safespeed.org.uk/
I for one am of the 'apropriate speed brigade'. From my experience, in terms of accident reduction, highway authorities are not interested in speed alone, but in relation to frequency of accidents and reasons. Residents however are 'scared' of speed alone and often request speed reduction measures even when there isnt an accident problem.
In terms of safety camera partnerships I know a business case has to be put forward to the DpT for a camera to be erected.(provided it meet the criteria as well).mmmmmmm.
have you seen
www.safespeed.org.uk/
I for one am of the 'apropriate speed brigade'. From my experience, in terms of accident reduction, highway authorities are not interested in speed alone, but in relation to frequency of accidents and reasons. Residents however are 'scared' of speed alone and often request speed reduction measures even when there isnt an accident problem.
In terms of safety camera partnerships I know a business case has to be put forward to the DpT for a camera to be erected.(provided it meet the criteria as well).mmmmmmm.
) seems fair enough and as you say most of the speed related deaths are caused by young idiots what would you say is the "right" age for young MALES to gain the priviledge of driving ?
I got my license at 18 and drove a car that was capable of 0-100 in 13.8 secs and topped out at 130mph and never came close to killing myself or even close to an accident even though I drove at high speeds (100+) a lot of the time.
I still think that I was too young and impressionable with peer pressure and shouldn't have been allowed to drive until at least 21.
Speed per see, is not the root cause of the accident, I believe ,and many a racing driver agrees, that the skill level of drivers need to be increased and from my own personal position I believe the immaturity of young drivers could be bought to bear by making them drive around a race circuit where they can see for themselves just how little they know about a speeding car and the dynamics that go with heavy bodies in high speed motion.
I intend having my son do all the road safety and racing courses possible as well as having him in karts for as long as I can before putting him at the mercy of the other road users.
I believe STUPIDITY is THE largest killer on the road and THAT is indisputable I don't care what anyone else believes. You only have to drive around for 10 mins before you see someone do somehing stupid that in the wrong circumstances WILL cause and accident.
btw I've lost my license 12 times for speeding and had one accident in 32 years of driving (6 months ago) in which I was doing 87kph in a 100kph zone and the car aquaplaned (no courses can help you then) rolled and destroyed itself and myself to some extent.
What irks me most is that they have NO gatsos on this horrific stretch of road where over 300 people have died in the last 10 years according to the local police and they attribute most of the deaths to poor road design and have been lobbying the survivors of accidents on this stretch of road to write to the govt to have the road upgraded (I'll bet then they put gatsos on them and claim they are saving lives !!! ffs) ,these are KNOWN blackspots and there are no scameras but 100 miles down the track on the 8 LANE hwy between Brisbane and the Gold Coast where I live they have mobile scameras on both sides and no blackspots on this stretch yet due to the newness of the road and it is as straight as a die and one of the few decent roads in the country
bugger me I've been ranting but the short reply is I agree, with addendum
I got my license at 18 and drove a car that was capable of 0-100 in 13.8 secs and topped out at 130mph and never came close to killing myself or even close to an accident even though I drove at high speeds (100+) a lot of the time.
I still think that I was too young and impressionable with peer pressure and shouldn't have been allowed to drive until at least 21.
Speed per see, is not the root cause of the accident, I believe ,and many a racing driver agrees, that the skill level of drivers need to be increased and from my own personal position I believe the immaturity of young drivers could be bought to bear by making them drive around a race circuit where they can see for themselves just how little they know about a speeding car and the dynamics that go with heavy bodies in high speed motion.
I intend having my son do all the road safety and racing courses possible as well as having him in karts for as long as I can before putting him at the mercy of the other road users.
I believe STUPIDITY is THE largest killer on the road and THAT is indisputable I don't care what anyone else believes. You only have to drive around for 10 mins before you see someone do somehing stupid that in the wrong circumstances WILL cause and accident.
btw I've lost my license 12 times for speeding and had one accident in 32 years of driving (6 months ago) in which I was doing 87kph in a 100kph zone and the car aquaplaned (no courses can help you then) rolled and destroyed itself and myself to some extent.
What irks me most is that they have NO gatsos on this horrific stretch of road where over 300 people have died in the last 10 years according to the local police and they attribute most of the deaths to poor road design and have been lobbying the survivors of accidents on this stretch of road to write to the govt to have the road upgraded (I'll bet then they put gatsos on them and claim they are saving lives !!! ffs) ,these are KNOWN blackspots and there are no scameras but 100 miles down the track on the 8 LANE hwy between Brisbane and the Gold Coast where I live they have mobile scameras on both sides and no blackspots on this stretch yet due to the newness of the road and it is as straight as a die and one of the few decent roads in the country
bugger me I've been ranting but the short reply is I agree, with addendum
Gazboy said:
Flemke, I posted this somewhere else in SP&L, but now can't find the topic:
3500 deaths on the road per year, if we subtract deaths caused by horses, cyclists and tractors, the drunk, the drugged, the unlicenced, the mot failier, the bloke with dodgy brakes, the dangerous (ie idiots on the wrong side of the road like the one that killed Mr Williams), the underage, the joyriders, the blind, the oaps who have refused to surrender their licence under medical grounds, kids who don't use the GCC and run straight out and foreigners, what is the total? Not many I guess.
Unfortunately I don't think that it's as easy as that - Flemke has roughed out a statistical assessment giving a very low frequency of a speeding driver causing an accident resulting in a fatality.
What is more difficult to negate is the pure physics of collisions - who/what ever is the cause of the accident. Taking Gazboy's list of exclusions above, the absolute cause of an accident may be the horse running out in the road or the drunk going the wrong way up a dual carriageway, but the gravity of the consequences of the accident depend on impact energy and the intrinsic safety in design of the vehicle(s) involved. Kinetic energy = 1/2mv^2 ; this is why the mantra "speed kills" will always be hard to counter - accident consequences are proportional to the square of the impact velocity.
However, none of this is a good excuse for a state run persecution programme such as exists in the UK now. I was brought up there during a period where the approach was educational, so didn't drive when p*ssed and was careful when crossing roads - it worked. Human nature is to trangress prohibitive laws - we seem to get a buzz out of it, e.g. 6 times more alcohol was drunk in Chicago during the prohibition than when alcohol was legal. The more they clamp down on drivers who exceed the speed limit, the more human nature will tend to transgression...
Very interesting analysis,however as has been pointed out, "speed kills" is a quick, easy to remember, emotive soundbite which has become a favourite with the hard of thinking.
We need to counteract this with soundbites of our own.
It is an undoubted fact that car ownership has liberated the masses (yes that includes working class people like me, and even the majority of Labour voters), and the creation and use of the road network has changed the face of Britain and our culture beyond recognition, and for the better.
For me, the mass introduction of speed cameras is part of a wider programme to create a more anti-car culture, fast sports cars have been one of the pinacles of aspiration for all levels of society for the last 50 years, and so far this hasn't changed (we must learn to love Max Power louts, united we stand etc.).
So lets start the ball rolling to create our own soundbites to remind people of what they stand to lose if they ignor what is going on.
"Cars Liberate" is one that springs to mind.
"Speed Matters" is another,
over to you more creative folks, ideas please.
We need to counteract this with soundbites of our own.
It is an undoubted fact that car ownership has liberated the masses (yes that includes working class people like me, and even the majority of Labour voters), and the creation and use of the road network has changed the face of Britain and our culture beyond recognition, and for the better.
For me, the mass introduction of speed cameras is part of a wider programme to create a more anti-car culture, fast sports cars have been one of the pinacles of aspiration for all levels of society for the last 50 years, and so far this hasn't changed (we must learn to love Max Power louts, united we stand etc.).
So lets start the ball rolling to create our own soundbites to remind people of what they stand to lose if they ignor what is going on.
"Cars Liberate" is one that springs to mind.
"Speed Matters" is another,
over to you more creative folks, ideas please.
The same kind of question has been examined by that statistician who created the formula for deciding the outcome of cricket matches when a natural conclusion isn't possible (don't ask me about cricket). His conclusion was that there is the same probability of dying in a road accident during your lifetime as there is of dying from an an accidental fall. I think this can be summed up as naff all percent of a tiny number. As suggested by Flemke's analysis.
4000 people die each year from accidents in the home but there's no draconian legislation, no big brother spy cams, and the gov't are to stop collecting stats on this - presumably as it embarrasses them regarding their motorist vilifying over-reaction to having the safest roads in the world...until the speed kills brigade came along our roads were getting even safer.
>> Edited by turbobloke on Tuesday 7th September 10:30
4000 people die each year from accidents in the home but there's no draconian legislation, no big brother spy cams, and the gov't are to stop collecting stats on this - presumably as it embarrasses them regarding their motorist vilifying over-reaction to having the safest roads in the world...until the speed kills brigade came along our roads were getting even safer.
>> Edited by turbobloke on Tuesday 7th September 10:30
Thanks for your considered replies.
A couple of comments:
Gazboy - Your numbers on drink- and drug-related RTA fatalities, which make up 20% of the total, must be accurate. I wonder, however, if there is more to the bare statistics than face value. Recently Paul Garvin, Chief Constable of Durham, was quoted as saying, "Drug-taking is becoming more of a problem. In 40% of fatal road accidents in this area one or more of the people involved have drugs in their system."
nel - Yes, we must acknowledge that damage increases as speed does, a correlation that commences as soon as there is any motion at all. The only way to prevent all road casualties is to prevent all road travel.
In the 19th century, in London alone there were more than 3,000 deaths per year caused by horses.
Perhaps I am mistaken, but I thought that my analysis encompassed your point. By counting fatalities themselves, I was restricting my survey to only the most extreme consequences. It was a worst-case analysis.
By the way, I believe that you are located or spend much time in France. This morning a friend of mine, driving on UK plates, was stopped for speeding near Lyon. While one gendarme was writing him up, the other searched for a radar detector by passing some sort of sensing device all over the front bumper, grille, and interior of the car. Have you heard anything about these detector detectors?
A couple of comments:
Gazboy - Your numbers on drink- and drug-related RTA fatalities, which make up 20% of the total, must be accurate. I wonder, however, if there is more to the bare statistics than face value. Recently Paul Garvin, Chief Constable of Durham, was quoted as saying, "Drug-taking is becoming more of a problem. In 40% of fatal road accidents in this area one or more of the people involved have drugs in their system."
nel - Yes, we must acknowledge that damage increases as speed does, a correlation that commences as soon as there is any motion at all. The only way to prevent all road casualties is to prevent all road travel.
In the 19th century, in London alone there were more than 3,000 deaths per year caused by horses.
Perhaps I am mistaken, but I thought that my analysis encompassed your point. By counting fatalities themselves, I was restricting my survey to only the most extreme consequences. It was a worst-case analysis.
By the way, I believe that you are located or spend much time in France. This morning a friend of mine, driving on UK plates, was stopped for speeding near Lyon. While one gendarme was writing him up, the other searched for a radar detector by passing some sort of sensing device all over the front bumper, grille, and interior of the car. Have you heard anything about these detector detectors?
nel said:
Kinetic energy = 1/2mv^2 ; this is why the mantra "speed kills" will always be hard to counter - accident consequences are proportional to the square of the impact velocity.
And you point would be? Just because a car has a larger kinetic energy it does NOT mean it it more likely to crash. What about a 38 ton HGV doing 55mph? A 1 ton car would need to do SQR(38*55^2)=339mph to carry the same kinetic energy. Should we therefore increase the speed limits to Mach 0.5 or perhaps limit trucks to 11.3mph to ensure they carry no more kinetic energy than a car doing 70mph?
As you can see any argument involving 1/2mv^2 laws is irrelevant. It may utlimately determine the outcome of an accident, but cause them? No, only people do that.
flemke said:
It is now generally agreed that no more than five percent of those deaths are the result of a driver's exceeding the speed limit,
Hello, this is not meant to detract from an excellent post I am just curious about the accuracy of the above statistic as it underpins the argument.
If it is a published/attributable figure it would make an argument more credible and less easy to undermine.
Also, judging by the length of time others have spent trying to uncover solid statistics on the subject if you could answer this it would save me a lot of time.
Thanks
custardtart said:
It is now generally agreed that no more than five percent of those deaths are the result of a driver's exceeding the speed limit,
Hello, this is not meant to detract from an excellent post I am just curious about the accuracy of the above statistic as it underpins the argument.
If it is a published/attributable figure it would make an argument more credible and less easy to undermine.
Also, judging by the length of time others have spent trying to uncover solid statistics on the subject if you could answer this it would save me a lot of time.
Thanks
Check the www.safespeed.org.uk website for the TRL document which illustrates the 5% figure.
308gt4 said:
I got my license at 18 ... I still think that I was too young and impressionable with peer pressure and shouldn't have been allowed to drive until at least 21.
Several friends and myself had small 50 and 125cc motorcross bikes when we were in our early teens, and tbh speeding in a car at 17 or 18 didn't hold the same appeal after that.
I guess the same could be said for those that played with karts as kids.
Maybe the answer is to start earlier, they could get kids on scooters at 14 or 15 with proper training at school (US style driver Ed.)? It'll surely make them better and more considerate drivers later.
>> Edited by rsvnigel on Tuesday 7th September 15:30
flemke said:
By the way, I believe that you are located or spend much time in France. This morning a friend of mine, driving on UK plates, was stopped for speeding near Lyon. While one gendarme was writing him up, the other searched for a radar detector by passing some sort of sensing device all over the front bumper, grille, and interior of the car. Have you heard anything about these detector detectors?
Nope - not heard about detector detectors - the sneaky gits. On a french Porsche forum that I frequent there is much talk about fitting of "systèmes embarqués" where the gizmo is properly integrated into the car to avoid visible evidence of a radar detector. I will look into it though as I was considering the option myself!
Mr2Mike said:
Kinetic energy = 1/2mv^2 ; this is why the mantra "speed kills" will always be hard to counter - accident consequences are proportional to the square of the impact velocity.
And you point would be? Just because a car has a larger kinetic energy it does NOT mean it it more likely to crash. What about a 38 ton HGV doing 55mph? A 1 ton car would need to do SQR(38*55^2)=339mph to carry the same kinetic energy. Should we therefore increase the speed limits to Mach 0.5 or perhaps limit trucks to 11.3mph to ensure they carry no more kinetic energy than a car doing 70mph?
As you can see any argument involving 1/2mv^2 laws is irrelevant. It may utlimately determine the outcome of an accident, but cause them? No, only people do that.
If you'd bothered to read my post rather than shooting from the hip you'd have noted that I never said that speed causes accidents, rather it determines the impact energy and hence the consequences.
If you were to walk out of a pub blind drunk into the path of a vehicle (hence drunken pedestrian is the cause of the accident), would you rather be hit by a car doing 25 mph or 50 mph?
nel said:
[quote=Mr2Mike]
[quote=nel]
If you were to walk out of a pub blind drunk into the path of a vehicle (hence drunken pedestrian is the cause of the accident), would you rather be hit by a car doing 25 mph or 50 mph?
I'd ratehr not be hit by a car in the first place. If someone gets so incapacitated that they can't control their actions I plainly see it as their own fault. There's been a recent situation like this in Edinburgh, they've closed the Cowgate in Edinburgh since last year late at night, usually after 8pm I think, simply because there were drunks falling into the street and being hit by cars. Rather than install railings or other sensible things, they did the cheapest.
XM5ER said:
Check the www.safespeed.org.uk website for the TRL document which illustrates the 5% figure.
Cheers, had a look and the TRL document - may have been looking at the wrong one as there was mention of a 5% figure but not in the same context as used here.
Thanks all the same though, I'll keep looking.
Dear Flemke
You conclude your analysis with the following:
“Assuming that these numbers are in the right ballpark, they lead me to conclude that a person who focuses on his or her driving and takes it seriously may be increasing risk to others by speeding, but that incremental increase is truly infinitesimal.”
I know that you and I, many of our acquaintances and the majority of people on this forum fall into this category.
Unfortunately “we happy few, we band of brothers” are in the minority, probably to a similar ratio as you conclude in your first post. LESS-THAN-ONE-IN-TWO-BILLION.
I hope it doesn’t sound smug to say that the speeding laws are not directed at us, although there are many that think they are. But at those who don’t fit into the category above. Those poor souls to who, driving is a drudge, a necessary evil, a way of getting from A to B.
Speed limits have been with us from day one and they aren’t going to go away. The best thing we can do is take them as part of the challenge of driving and pray that our loved ones are just a little safer because of them.
I will add that I don’t approve of inappropriate cameras and speed limits. But surely the “sleeping policeman” has to be the most unjust deterrent of all.
Robbie
>> Edited by RobbieMeister on Tuesday 7th September 17:10
>> Edited by RobbieMeister on Tuesday 7th September 17:11
You conclude your analysis with the following:
“Assuming that these numbers are in the right ballpark, they lead me to conclude that a person who focuses on his or her driving and takes it seriously may be increasing risk to others by speeding, but that incremental increase is truly infinitesimal.”
I know that you and I, many of our acquaintances and the majority of people on this forum fall into this category.
Unfortunately “we happy few, we band of brothers” are in the minority, probably to a similar ratio as you conclude in your first post. LESS-THAN-ONE-IN-TWO-BILLION.
I hope it doesn’t sound smug to say that the speeding laws are not directed at us, although there are many that think they are. But at those who don’t fit into the category above. Those poor souls to who, driving is a drudge, a necessary evil, a way of getting from A to B.
Speed limits have been with us from day one and they aren’t going to go away. The best thing we can do is take them as part of the challenge of driving and pray that our loved ones are just a little safer because of them.
I will add that I don’t approve of inappropriate cameras and speed limits. But surely the “sleeping policeman” has to be the most unjust deterrent of all.
Robbie
>> Edited by RobbieMeister on Tuesday 7th September 17:10
>> Edited by RobbieMeister on Tuesday 7th September 17:11
Hmmm, a walk a little too far in the park for my liking. I'm sure the statistical analysis is greeted by the audience for which it was intended, but statistics have a habit of agreeing with their creator.
I sometimes think the police play this game for the benefit of us joe public.
I don't believe it is possible to isolate speed as a causative factor, but it is possible and probably sensible to view it as a contributery.
Therefore to isolate, for example, drugs as a cause and ignore the speed driven by the druggy is simply as bad as the police deciding that speed kills purely because it provides an easily measurable target.
You cannot decide which is the cause on a venn diagram and ignore the obvious overlap to improve your figures.
I'll give you a for instance. I have a patient who is a known heroine drug addict, controlled on a daily maintenance dose of methodone which would probably kill most normal people. Not only does she hold down a quite high power job but she drives as part of it.
Should she have an accident, when would she fall on your venn diagram and would that be the same place the police would place her?
I sometimes think the police play this game for the benefit of us joe public.
I don't believe it is possible to isolate speed as a causative factor, but it is possible and probably sensible to view it as a contributery.
Therefore to isolate, for example, drugs as a cause and ignore the speed driven by the druggy is simply as bad as the police deciding that speed kills purely because it provides an easily measurable target.
You cannot decide which is the cause on a venn diagram and ignore the obvious overlap to improve your figures.
I'll give you a for instance. I have a patient who is a known heroine drug addict, controlled on a daily maintenance dose of methodone which would probably kill most normal people. Not only does she hold down a quite high power job but she drives as part of it.
Should she have an accident, when would she fall on your venn diagram and would that be the same place the police would place her?
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