How many die later from serious injuries on our roads?
in [UK Drivers]
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From: Doug on 25 Feb 2010 13:08 On 20 Feb, 18:59, "Nightjar <\"cpb\"@" <"insertmysurnamehere> wrote: > Doug wrote: > > On 19 Feb, 02:36, "Nightjar <\"cpb\"@" <"insertmysurnamehere> wrote: > ... > >> As I said ealrier, doubling the danger to half the number of people > >> should mean that the accident numbers remain roughly the same, so the > >> you need to explain the entire 78% reduction. > > > According to your own numbers there are almost 30 million vehicles and > > if you use an average occupancy of 1.6 that is 48million, about the > > same as the entire adult population. > > According to my numbers, there are 400 cars owned per 1000 population. > With an estimated 65 million population, that is 26 million cars owned. > The DVAL figure is 26,208,000. However, cars owned is not the same as > the number of cars in use at any one time. If you assume that the > percentage of cars in use remain roughly constant, then the number of > cars owned is a rough guide to the relative risk levels. However, it > won't work as the basis for working out how many people are travelling > in cars compared to those not. For that, you have to use the numer of > cars in use which, on a busy bank holiday, is around 10 million. Using > your 1.6 occupants per car, that would give 16 million people in car and > 49 million not in cars, almost exactly the reverse of your figures. Of > course, on a normal day, the numbers of cars on the road will be lower > than on a buy bank holiday. Also, you cannot assume that the 0.6 > passenger is someone who would otherwise be a pedestrian. I live in a > predomiantly rural area, so nobody I know does not own a car, from which > it follows that anyone travelling with me is a car owner who is, > temporarily not using their own car. > What you have not factored in is how many pedestrians there are on the streets. Many will be at home or at work. So how many of the 49 million are actually on the streets to be killed or injured by drivers? Obviously, if that number has dropped recently, because they are in cars instead, the streets will appear to be safer. > ... > > >> I think you are making an assumption to support your preconceptions. > >> When I go shopping in one of the nearby towns, parking tends to be > >> charged for and of limited availability or free but time restricted, so > >> I usually park outside the parking control zones, which can involve a > >> half-hour walk to the shops. That usually means I take as long walking > >> to the shopping area as it takes me to drive to the town. The number of > >> cars parked in the outer areas when the shops are open suggests that I > >> am not alone in doing this. > > > Anecdotal. > > OK. I'll put it terms you can understand. Remember all those cars parked > on the roads that you complain about? Every one represents a car owner > who is not being a motorist at the time. > Contrast this with the rush hour and the Saturday shopping rush. > ... > > >> You would have to say that, but the fact is that modern cars are very > >> much less likely to injure a pedestrian at town speeds than ones from 40 > >> years ago. > > > Speculative. > > Proven engineering fact. > Again, then why are the protection ratings so low? > ... > > >>> Let me know when they start fitting thick foam and > >>> airbags to the FRONT of cars and you might then have a point. > >> Neither would be an improvement. Cars already have carefully designed > >> deformable structures that are more effective than foam. By bending and > >> staying bent, they absorbe more energy and don't try to throw the > >> pedestrian off in a random direction, as a resiliant foam might. > > > Then why are their pedestrian ratings so low? > > Because of the inherent difficulties of protecting someone in an > uncontrolled environment. The occupants of the car are strapped inside a > controlled environment, the behaviour of which can be very accurately > determined during an accident. Interactions outside that environment > cannot be predicted in the same way, which means that the same levels of > protection cannot be achieved, even in theory. > It can but it would make cars look ridiculous. > > >> Air bags are effective inside a car because they inflate before the > >> occupants hit the internal structure, which they do by detecting an > >> unusually high deceleration. It would probably be impossible to design a > >> method of deployment that would work for pedestrians, but not go off > >> while braking hard or when parking. However, even if that were possible, > >> the effect would be to push the pedestrian over, where they are > >> vulnerable to being run over, rather than rolling them over the bonnet > >> and out of the way of the wheels, as modern cars are designed to do. > > > If the airbag was placed low it would roll them over the bonnet and > > avoid breaking the legs. It would be deployed whenever the large foam > > bumper encountered an obstacle. > > Which will usually be when parking. As I said, there are serious > practical problems with your suggestions. > Yes its easier to just kill pedestrians than to interfere with motoring. -- UK Radical Campaigns www.zing.icom43.net A driving licence is a licence to kill.
From: Marie on 25 Feb 2010 13:21 On Feb 25, 6:08 pm, Doug <jag...(a)riseup.net> wrote: > On 20 Feb, 18:59, "Nightjar <\"cpb\"@" <"insertmysurnamehere> wrote: > > > Doug wrote: > > > On 19 Feb, 02:36, "Nightjar <\"cpb\"@" <"insertmysurnamehere> wrote: > > ... > > >> As I said ealrier, doubling the danger to half the number of people > > >> should mean that the accident numbers remain roughly the same, so the > > >> you need to explain the entire 78% reduction. > > > > According to your own numbers there are almost 30 million vehicles and > > > if you use an average occupancy of 1.6 that is 48million, about the > > > same as the entire adult population. > > > According to my numbers, there are 400 cars owned per 1000 population. > > With an estimated 65 million population, that is 26 million cars owned. > > The DVAL figure is 26,208,000. However, cars owned is not the same as > > the number of cars in use at any one time. If you assume that the > > percentage of cars in use remain roughly constant, then the number of > > cars owned is a rough guide to the relative risk levels. However, it > > won't work as the basis for working out how many people are travelling > > in cars compared to those not. For that, you have to use the numer of > > cars in use which, on a busy bank holiday, is around 10 million. Using > > your 1.6 occupants per car, that would give 16 million people in car and > > 49 million not in cars, almost exactly the reverse of your figures. Of > > course, on a normal day, the numbers of cars on the road will be lower > > than on a buy bank holiday. Also, you cannot assume that the 0.6 > > passenger is someone who would otherwise be a pedestrian. I live in a > > predomiantly rural area, so nobody I know does not own a car, from which > > it follows that anyone travelling with me is a car owner who is, > > temporarily not using their own car. > > What you have not factored in is how many pedestrians there are on the > streets. Many will be at home or at work. So how many of the 49 > million are actually on the streets to be killed or injured by > drivers? Obviously, if that number has dropped recently, because they > are in cars instead, the streets will appear to be safer. Wriggle, wriggle. > > > ... > > > >> I think you are making an assumption to support your preconceptions. > > >> When I go shopping in one of the nearby towns, parking tends to be > > >> charged for and of limited availability or free but time restricted, so > > >> I usually park outside the parking control zones, which can involve a > > >> half-hour walk to the shops. That usually means I take as long walking > > >> to the shopping area as it takes me to drive to the town. The number of > > >> cars parked in the outer areas when the shops are open suggests that I > > >> am not alone in doing this. > > > > Anecdotal. > > > OK. I'll put it terms you can understand. Remember all those cars parked > > on the roads that you complain about? Every one represents a car owner > > who is not being a motorist at the time. > > Contrast this with the rush hour and the Saturday shopping rush.> . Sigh ... > > > >> You would have to say that, but the fact is that modern cars are very > > >> much less likely to injure a pedestrian at town speeds than ones from 40 > > >> years ago. > > > > Speculative. > > > Proven engineering fact. > > Again, then why are the protection ratings so low? Sigh sigh > > > ... > > > >>> Let me know when they start fitting thick foam and > > >>> airbags to the FRONT of cars and you might then have a point. > > >> Neither would be an improvement. Cars already have carefully designed > > >> deformable structures that are more effective than foam. By bending and > > >> staying bent, they absorbe more energy and don't try to throw the > > >> pedestrian off in a random direction, as a resiliant foam might. > > > > Then why are their pedestrian ratings so low? > > > Because of the inherent difficulties of protecting someone in an > > uncontrolled environment. The occupants of the car are strapped inside a > > controlled environment, the behaviour of which can be very accurately > > determined during an accident. Interactions outside that environment > > cannot be predicted in the same way, which means that the same levels of > > protection cannot be achieved, even in theory. > > It can but it would make cars look ridiculous. More rubbish posted by Doug. > > > > > >> Air bags are effective inside a car because they inflate before the > > >> occupants hit the internal structure, which they do by detecting an > > >> unusually high deceleration. It would probably be impossible to design a > > >> method of deployment that would work for pedestrians, but not go off > > >> while braking hard or when parking. However, even if that were possible, > > >> the effect would be to push the pedestrian over, where they are > > >> vulnerable to being run over, rather than rolling them over the bonnet > > >> and out of the way of the wheels, as modern cars are designed to do. > > > > If the airbag was placed low it would roll them over the bonnet and > > > avoid breaking the legs. It would be deployed whenever the large foam > > > bumper encountered an obstacle. > > > Which will usually be when parking. As I said, there are serious > > practical problems with your suggestions. > > Yes its easier to just kill pedestrians than to interfere with > motoring. Oh look, a bit more bollox posted by Doug at the end. > > -- > UK Radical Campaignswww.zing.icom43.net > A driving licence is a licence to kill. Marie
From: "Nightjar "cpb" on 25 Feb 2010 16:34 Doug wrote: > On 20 Feb, 18:59, "Nightjar <\"cpb\"@" <"insertmysurnamehere> wrote: >> Doug wrote: >>> On 19 Feb, 02:36, "Nightjar <\"cpb\"@" <"insertmysurnamehere> wrote: >> ... >>>> As I said ealrier, doubling the danger to half the number of people >>>> should mean that the accident numbers remain roughly the same, so the >>>> you need to explain the entire 78% reduction. >>> According to your own numbers there are almost 30 million vehicles and >>> if you use an average occupancy of 1.6 that is 48million, about the >>> same as the entire adult population. >> According to my numbers, there are 400 cars owned per 1000 population. >> With an estimated 65 million population, that is 26 million cars owned. >> The DVAL figure is 26,208,000. However, cars owned is not the same as >> the number of cars in use at any one time. If you assume that the >> percentage of cars in use remain roughly constant, then the number of >> cars owned is a rough guide to the relative risk levels. However, it >> won't work as the basis for working out how many people are travelling >> in cars compared to those not. For that, you have to use the numer of >> cars in use which, on a busy bank holiday, is around 10 million. Using >> your 1.6 occupants per car, that would give 16 million people in car and >> 49 million not in cars, almost exactly the reverse of your figures. Of >> course, on a normal day, the numbers of cars on the road will be lower >> than on a buy bank holiday. Also, you cannot assume that the 0.6 >> passenger is someone who would otherwise be a pedestrian. I live in a >> predomiantly rural area, so nobody I know does not own a car, from which >> it follows that anyone travelling with me is a car owner who is, >> temporarily not using their own car. >> > What you have not factored in is how many pedestrians there are on the > streets. Many will be at home or at work. So how many of the 49 > million are actually on the streets to be killed or injured by > drivers? Around three times as many as there would be using your calculations. > Obviously, if that number has dropped recently, because they > are in cars instead, the streets will appear to be safer. Not to a large enough extent as to explain the drop in pedestrian casualties. >> ... >> >>>> I think you are making an assumption to support your preconceptions. >>>> When I go shopping in one of the nearby towns, parking tends to be >>>> charged for and of limited availability or free but time restricted, so >>>> I usually park outside the parking control zones, which can involve a >>>> half-hour walk to the shops. That usually means I take as long walking >>>> to the shopping area as it takes me to drive to the town. The number of >>>> cars parked in the outer areas when the shops are open suggests that I >>>> am not alone in doing this. >>> Anecdotal. >> OK. I'll put it terms you can understand. Remember all those cars parked >> on the roads that you complain about? Every one represents a car owner >> who is not being a motorist at the time. >> > Contrast this with the rush hour and the Saturday shopping rush. There are still a lot of parked cars during those periods. On Saturdays mine will be among them in a nearby town. >> ... >> >>>> You would have to say that, but the fact is that modern cars are very >>>> much less likely to injure a pedestrian at town speeds than ones from 40 >>>> years ago. >>> Speculative. >> Proven engineering fact. >> > Again, then why are the protection ratings so low? Explained in my next paragraph. >> ... >> >>>>> Let me know when they start fitting thick foam and >>>>> airbags to the FRONT of cars and you might then have a point. >>>> Neither would be an improvement. Cars already have carefully designed >>>> deformable structures that are more effective than foam. By bending and >>>> staying bent, they absorbe more energy and don't try to throw the >>>> pedestrian off in a random direction, as a resiliant foam might. >>> Then why are their pedestrian ratings so low? >> Because of the inherent difficulties of protecting someone in an >> uncontrolled environment. The occupants of the car are strapped inside a >> controlled environment, the behaviour of which can be very accurately >> determined during an accident. Interactions outside that environment >> cannot be predicted in the same way, which means that the same levels of >> protection cannot be achieved, even in theory. >> > It can but it would make cars look ridiculous. Remind me which university granted you a degree in engineering? >>>> Air bags are effective inside a car because they inflate before the >>>> occupants hit the internal structure, which they do by detecting an >>>> unusually high deceleration. It would probably be impossible to design a >>>> method of deployment that would work for pedestrians, but not go off >>>> while braking hard or when parking. However, even if that were possible, >>>> the effect would be to push the pedestrian over, where they are >>>> vulnerable to being run over, rather than rolling them over the bonnet >>>> and out of the way of the wheels, as modern cars are designed to do. >>> If the airbag was placed low it would roll them over the bonnet and >>> avoid breaking the legs. It would be deployed whenever the large foam >>> bumper encountered an obstacle. >> Which will usually be when parking. As I said, there are serious >> practical problems with your suggestions. >> > Yes its easier to just kill pedestrians than to interfere with > motoring. Your suggestions would not have any significant effect on motoring, but neither would they have any significant effect on pedestrian safety. Colin Bignell
From: Doug on 26 Feb 2010 01:58 On 25 Feb, 21:34, "Nightjar <\"cpb\"@" <"insertmysurnamehere> wrote: > Doug wrote: > > On 20 Feb, 18:59, "Nightjar <\"cpb\"@" <"insertmysurnamehere> wrote: > >> Doug wrote: > >>> On 19 Feb, 02:36, "Nightjar <\"cpb\"@" <"insertmysurnamehere> wrote: > >> ... > >>>> As I said ealrier, doubling the danger to half the number of people > >>>> should mean that the accident numbers remain roughly the same, so the > >>>> you need to explain the entire 78% reduction. > >>> According to your own numbers there are almost 30 million vehicles and > >>> if you use an average occupancy of 1.6 that is 48million, about the > >>> same as the entire adult population. > >> According to my numbers, there are 400 cars owned per 1000 population. > >> With an estimated 65 million population, that is 26 million cars owned.. > >> The DVAL figure is 26,208,000. However, cars owned is not the same as > >> the number of cars in use at any one time. If you assume that the > >> percentage of cars in use remain roughly constant, then the number of > >> cars owned is a rough guide to the relative risk levels. However, it > >> won't work as the basis for working out how many people are travelling > >> in cars compared to those not. For that, you have to use the numer of > >> cars in use which, on a busy bank holiday, is around 10 million. Using > >> your 1.6 occupants per car, that would give 16 million people in car and > >> 49 million not in cars, almost exactly the reverse of your figures. Of > >> course, on a normal day, the numbers of cars on the road will be lower > >> than on a buy bank holiday. Also, you cannot assume that the 0.6 > >> passenger is someone who would otherwise be a pedestrian. I live in a > >> predomiantly rural area, so nobody I know does not own a car, from which > >> it follows that anyone travelling with me is a car owner who is, > >> temporarily not using their own car. > > > What you have not factored in is how many pedestrians there are on the > > streets. Many will be at home or at work. So how many of the 49 > > million are actually on the streets to be killed or injured by > > drivers? > > Around three times as many as there would be using your calculations. > How do you work that out? What source tells you how many are on the streets compared to at home or work? > > > Obviously, if that number has dropped recently, because they > > are in cars instead, the streets will appear to be safer. > > Not to a large enough extent as to explain the drop in pedestrian > casualties. > On the contrary. > > > >> ... > > >>>> I think you are making an assumption to support your preconceptions. > >>>> When I go shopping in one of the nearby towns, parking tends to be > >>>> charged for and of limited availability or free but time restricted, so > >>>> I usually park outside the parking control zones, which can involve a > >>>> half-hour walk to the shops. That usually means I take as long walking > >>>> to the shopping area as it takes me to drive to the town. The number of > >>>> cars parked in the outer areas when the shops are open suggests that I > >>>> am not alone in doing this. > >>> Anecdotal. > >> OK. I'll put it terms you can understand. Remember all those cars parked > >> on the roads that you complain about? Every one represents a car owner > >> who is not being a motorist at the time. > > > Contrast this with the rush hour and the Saturday shopping rush. > > There are still a lot of parked cars during those periods. On Saturdays > mine will be among them in a nearby town. > And there are lots in motion on our roads. > > >> ... > > >>>> You would have to say that, but the fact is that modern cars are very > >>>> much less likely to injure a pedestrian at town speeds than ones from 40 > >>>> years ago. > >>> Speculative. > >> Proven engineering fact. > > > Again, then why are the protection ratings so low? > > Explained in my next paragraph. > The fact that the ratings are low means they are likely to kill or injure a pedestrian. > > > >> ... > > >>>>> Let me know when they start fitting thick foam and > >>>>> airbags to the FRONT of cars and you might then have a point. > >>>> Neither would be an improvement. Cars already have carefully designed > >>>> deformable structures that are more effective than foam. By bending and > >>>> staying bent, they absorbe more energy and don't try to throw the > >>>> pedestrian off in a random direction, as a resiliant foam might. > >>> Then why are their pedestrian ratings so low? > >> Because of the inherent difficulties of protecting someone in an > >> uncontrolled environment. The occupants of the car are strapped inside a > >> controlled environment, the behaviour of which can be very accurately > >> determined during an accident. Interactions outside that environment > >> cannot be predicted in the same way, which means that the same levels of > >> protection cannot be achieved, even in theory. > > > It can but it would make cars look ridiculous. > > Remind me which university granted you a degree in engineering? > Stop wriggling and stick to the point. > > > >>>> Air bags are effective inside a car because they inflate before the > >>>> occupants hit the internal structure, which they do by detecting an > >>>> unusually high deceleration. It would probably be impossible to design a > >>>> method of deployment that would work for pedestrians, but not go off > >>>> while braking hard or when parking. However, even if that were possible, > >>>> the effect would be to push the pedestrian over, where they are > >>>> vulnerable to being run over, rather than rolling them over the bonnet > >>>> and out of the way of the wheels, as modern cars are designed to do. > >>> If the airbag was placed low it would roll them over the bonnet and > >>> avoid breaking the legs. It would be deployed whenever the large foam > >>> bumper encountered an obstacle. > >> Which will usually be when parking. As I said, there are serious > >> practical problems with your suggestions. > > > Yes its easier to just kill pedestrians than to interfere with > > motoring. > > Your suggestions would not have any significant effect on motoring, but > neither would they have any significant effect on pedestrian safety. > Obviously being hit by thick foam or an airbag is much better than being hit by metal but they wouldn't look good on the front of a car for two reasons... a) aesthetic b) makes the source of danger look all too obvious. In other words it wouldn't sell cars despite being safer for pedestrians. -- UK Radical Campaigns www.zing.icom43.net A driving licence is a licence to kill.
From: "Nightjar "cpb" on 26 Feb 2010 03:32
Doug wrote: > On 25 Feb, 21:34, "Nightjar <\"cpb\"@" <"insertmysurnamehere> wrote: >> Doug wrote: >>> On 20 Feb, 18:59, "Nightjar <\"cpb\"@" <"insertmysurnamehere> wrote: >>>> Doug wrote: >>>>> On 19 Feb, 02:36, "Nightjar <\"cpb\"@" <"insertmysurnamehere> wrote: >>>> ... >>>>>> As I said ealrier, doubling the danger to half the number of people >>>>>> should mean that the accident numbers remain roughly the same, so the >>>>>> you need to explain the entire 78% reduction. >>>>> According to your own numbers there are almost 30 million vehicles and >>>>> if you use an average occupancy of 1.6 that is 48million, about the >>>>> same as the entire adult population. >>>> According to my numbers, there are 400 cars owned per 1000 population. >>>> With an estimated 65 million population, that is 26 million cars owned. >>>> The DVAL figure is 26,208,000. However, cars owned is not the same as >>>> the number of cars in use at any one time. If you assume that the >>>> percentage of cars in use remain roughly constant, then the number of >>>> cars owned is a rough guide to the relative risk levels. However, it >>>> won't work as the basis for working out how many people are travelling >>>> in cars compared to those not. For that, you have to use the numer of >>>> cars in use which, on a busy bank holiday, is around 10 million. Using >>>> your 1.6 occupants per car, that would give 16 million people in car and >>>> 49 million not in cars, almost exactly the reverse of your figures. Of >>>> course, on a normal day, the numbers of cars on the road will be lower >>>> than on a buy bank holiday. Also, you cannot assume that the 0.6 >>>> passenger is someone who would otherwise be a pedestrian. I live in a >>>> predomiantly rural area, so nobody I know does not own a car, from which >>>> it follows that anyone travelling with me is a car owner who is, >>>> temporarily not using their own car. >>> What you have not factored in is how many pedestrians there are on the >>> streets. Many will be at home or at work. So how many of the 49 >>> million are actually on the streets to be killed or injured by >>> drivers? >> Around three times as many as there would be using your calculations. >> > How do you work that out? You had 48 million people in cars, leaving 17 million not in cars. My figures suggest there will be a maximum, on the busiest days, of 16 million in cars, leaving 49 million not in cars. 49/17=2.88 > What source tells you how many are on the > streets compared to at home or work? You keep confusing ratios with absolute numbers. I said about three times as many as with your calculations. That is a ratio that is justified by the calculation above. >>> Obviously, if that number has dropped recently, because they >>> are in cars instead, the streets will appear to be safer. >> Not to a large enough extent as to explain the drop in pedestrian >> casualties. >> > On the contrary. You would have to keep repeating that view, as to do anything else would mean that you accept that one of your most dearly held prejudices is wrong. However, you are wrong and, to avoid this descending into panto, you can take that as a repeating reply to any protestations you make to the contrary. >> >>>> ... >>>>>> I think you are making an assumption to support your preconceptions. >>>>>> When I go shopping in one of the nearby towns, parking tends to be >>>>>> charged for and of limited availability or free but time restricted, so >>>>>> I usually park outside the parking control zones, which can involve a >>>>>> half-hour walk to the shops. That usually means I take as long walking >>>>>> to the shopping area as it takes me to drive to the town. The number of >>>>>> cars parked in the outer areas when the shops are open suggests that I >>>>>> am not alone in doing this. >>>>> Anecdotal. >>>> OK. I'll put it terms you can understand. Remember all those cars parked >>>> on the roads that you complain about? Every one represents a car owner >>>> who is not being a motorist at the time. >>> Contrast this with the rush hour and the Saturday shopping rush. >> There are still a lot of parked cars during those periods. On Saturdays >> mine will be among them in a nearby town. >> > And there are lots in motion on our roads. The parked cars are still car owners who are being something other than motorists, be it pedestrians, cyclists, bus users, holidaymakers or couch potatoes. >>>> ... >>>>>> You would have to say that, but the fact is that modern cars are very >>>>>> much less likely to injure a pedestrian at town speeds than ones from 40 >>>>>> years ago. >>>>> Speculative. >>>> Proven engineering fact. >>> Again, then why are the protection ratings so low? >> Explained in my next paragraph. >> > The fact that the ratings are low means they are likely to kill or > injure a pedestrian. There are lots of engineers in the motor industry trying to improve pedestrian protection, but the fact remains that they are limited by the fact that the pedestrian is in an uncontrolled environment. Of course, to kill or injure a pedestrian, it is first necessary to hit them and I take the view that it is better to avoid doing that at all. Unfortunately, that would take a strong political will, as it would involve setting higher standards for all drivers (as well as better educating other road users), which would deny a lot of people of what they view as a right to drive. Of course there would be other benefits, such as reducing congestion and increasing demand for public transport, meaning that there could be more investment in improving that. >> >>>> ... >>>>>>> Let me know when they start fitting thick foam and >>>>>>> airbags to the FRONT of cars and you might then have a point. >>>>>> Neither would be an improvement. Cars already have carefully designed >>>>>> deformable structures that are more effective than foam. By bending and >>>>>> staying bent, they absorbe more energy and don't try to throw the >>>>>> pedestrian off in a random direction, as a resiliant foam might. >>>>> Then why are their pedestrian ratings so low? >>>> Because of the inherent difficulties of protecting someone in an >>>> uncontrolled environment. The occupants of the car are strapped inside a >>>> controlled environment, the behaviour of which can be very accurately >>>> determined during an accident. Interactions outside that environment >>>> cannot be predicted in the same way, which means that the same levels of >>>> protection cannot be achieved, even in theory. >>> It can but it would make cars look ridiculous. >> Remind me which university granted you a degree in engineering? >> > Stop wriggling and stick to the point. That is the point. I am a qualified engineer and you are not. >> >>>>>> Air bags are effective inside a car because they inflate before the >>>>>> occupants hit the internal structure, which they do by detecting an >>>>>> unusually high deceleration. It would probably be impossible to design a >>>>>> method of deployment that would work for pedestrians, but not go off >>>>>> while braking hard or when parking. However, even if that were possible, >>>>>> the effect would be to push the pedestrian over, where they are >>>>>> vulnerable to being run over, rather than rolling them over the bonnet >>>>>> and out of the way of the wheels, as modern cars are designed to do. >>>>> If the airbag was placed low it would roll them over the bonnet and >>>>> avoid breaking the legs. It would be deployed whenever the large foam >>>>> bumper encountered an obstacle. >>>> Which will usually be when parking. As I said, there are serious >>>> practical problems with your suggestions. >>> Yes its easier to just kill pedestrians than to interfere with >>> motoring. >> Your suggestions would not have any significant effect on motoring, but >> neither would they have any significant effect on pedestrian safety. >> > Obviously being hit by thick foam or an airbag is much better than > being hit by metal ... It may appear obvious to the uniformed, but, as I have pointed out, you want a material that absorbs energy by plastic deformation (i.e it stays in the shape it bends to), such as metal, not one that absorbs energy by elastic deformation (i.e it springs back to its original shape), such as a resiliant foam. Not only can plastic deformation absorb more energy, which is desirable, but elastic deformation feeds a significant part of the energy it absorbs back into whatever deforms it, which is not desirable when it is a pedestrian who will be thrown off in an unpredictable direction by the recovery. Similarly, air bags are good in the controlled environment of a car interior, but will have unpredictable results if used outside the car, even if the engineering problem of distinguishing between a pedestrian and any other relatively light impact can be overcome. > but they wouldn't look good on the front of a car > for two reasons... > > a) aesthetic > b) makes the source of danger look all too obvious. Both, if real, could easily be overcome by marketing. > In other words it wouldn't sell cars despite being safer for > pedestrians. As I have pointed out, your suggestsions could actually endanger pedestrians more. Colin BIgnell |