Seat belts and helmets

[swansonj]

(Lifted from a different thread because this is a change of subject)

Front seat belt laws are largely paternalistic, but quite apart from uclown's point, there is no comparison to be drawn, because there is no right to drive a car on the public highway in the first place, so whatever reasonable restrictions we choose to place on it are fair enough, especially restrictions which can be demonstrated to reduce deaths and serious injuries.

Are we sure? Compared to cycle helmets, the physics whereby seat belts should reduce deaths and injuries is much clearer, so there is certainly an expectation that seat belts should save lives, once an accident has happened. But risk compensation applies to seat belts as well as to helmets. This graph comes from John Adams:

You can see a downward blip coinciding with the introduction of the breathalyser in 1967 (though not any obvious long-term effect), but it would be a determined person who claimed any noticeable effect of the massive increase in seat-belt use following the legislation in 1982 [edit - legislation passed 1982, came into force 1983].

To me, that is a pretty powerful suggestion that risk compensation is indeed at work (with extra evidence coming from the increase in cycle/pedestrian injuries), but I'd be interested if anyone else has an alternative explanation or a critique of Adams' arguments or statistics.

Mind you, if it's hard work trying to persuade people to be be led by evidence rather than assertion on cycle helmets, just imagine trying to do that for seat belts...

 

[MontyVeda]

what happened in the late 1940's? that appears to be the start of the decline.

 

[Ern1e]

Just to add another dimension onto this ! take a look at how vehicles have been engineered to absorb impacts and crumple to also save the occupants inside them i.e. air bags front side etc so now not only just seat belts the whole vehicle is now a moving saftey zone.So what as the humble bicylist got ? yep a styro foam helmet oh deep joy how safe do these items make me feel ?

 

[Wobblers]

Just to add another dimension onto this ! take a look at how vehicles have been engineered to absorb impacts and crumple to also save the occupants inside them i.e. air bags front side etc so now not only just seat belts the whole vehicle is now a moving saftey zone.So what as the humble bicylist got ? yep a styro foam helmet oh deep joy how safe do these items make me feel ?

Ah, you forget: a helmet's purpose isn't to make you feel better, it's to make the motorist feel better about not giving you enough space...

 

[MontyVeda]

here's another graph... it's quite different* to the one in the OP as it shows a steady increase from 1945ish-1965ish

source: wiki-innit

what caused the sharp decline circa 1990? ABS brakes maybe?
and another around 2007ish... more and more airbags?

I'm just guessing by the way.

*it should be pointed out that it's just figures, not per billion Km as shown in the OPs chart

 

[Ern1e]

Ah, you forget: a helmet's purpose isn't to make you feel better, it's to make the motorist feel better about not giving you enough space...

Ah thankyou @McWobble for clearing that issue up so simply ! I shall now ride with a refreshed feeling of "Impending Dome" also is it helpful if one's lid has a little light on the back of it ?

 

[theclaud]

Are we sure?

No. I just took a punt on it. From the point of view of the restriction of freedom, I don't think driving freedoms matter much. If it gives the illusion of being a significant safety measure when it isn't, then that is a problem. There's a joke that surfaces on the forum occasionally that drivers should have a spike in the steering column to focus their minds - I wouldn't go that far but I think there's a case for reducing the feelings of invulnerability of those who present a danger to others.

 

[ufkacbln]

If brakes have improved, then why do we need to have high friction surfaces at virtually every junction?

 

[swansonj]

No. I just took a punt on it. From the point of view of the restriction of freedom, I don't think driving freedoms matter much. If it gives the illusion of being a significant safety measure when it isn't, then that is a problem. There's a joke that surfaces on the forum occasionally that drivers should have a spike in the steering column to focus their minds - I wouldn't go that far but I think there's a case for reducing the feelings of invulnerability of those who present a danger to others.

I have certainly advanced the metal spike argument before. I used to argue it would eliminate all road arguments. I now tend to think it wouldn't. The logic of Adams' arguments and his statistics is that risk compensation by drivers is almost perfect - whatever measures are introduced, they will adjust their driving behaviour to return to the same (progressively decreasing) level of risk. Thus, seat belts, ABS*, better road surfaces etc have all been seamlessly absorbed, presumably leading to faster driving or taking less care, but not significantly impacting on risk; and logically, spikes in steering wheels would be expected to lead to slower journeys but no great lasting change to risks for drivers.

And there's the nub - it's risks for drivers that drivers adjust their behaviour to control. Every (or at least most) safety measure for cars allows drivers to drive faster, or with less care, without increasing their own risk - but thereby significantly increasing the risks for vulnerable road users, cyclists and pedestrians. Unless someone can come up with an alternative explanation of the statistics, it seems to me entirely possible that the introduction of mandatory seat belts has barely saved a single driver's life but has killed quite a few cyclists and pedestrians.

*Adams cites some research in America suggesting that the introduction of ABS led to a reduction in rear-ending collisions, particularly in bad weather, but that this was entirely eaten up by an increase in leaving-the-highway accidents, presumably as people were tempted by their feeling of invulnerability to drive faster, beyond the capacity of ABS to retrieve the situation.

 

[srw]

no great lasting change to risks for drivers.

But your graph shows that there has been a significant change to risk for drivers...

but thereby significantly increasing the risks for vulnerable road users, cyclists and pedestrians. Unless someone can come up with an alternative explanation of the statistics, it seems to me entirely possible that the introduction of mandatory seat belts has barely saved a single driver's life but has killed quite a few cyclists and pedestrians.

I'm not going to go searching now, but my memory is there has also been a commensurate reduction in deaths of cyclists and pedestrians.

Yours is an easy hypothesis to test, and the data is easily available. If making driving safer for drivers has made it more dangerous for others, then when you divide pedestrian and cyclist deaths by billion vehicle kilometres you ought to see an upward trend. I don't think you will.

 

[srw]

Driving is a simple, overlearned skill now, not a special skill that people hone and practise with pride. There's a mindset of lack of care inherent in that - a kind of absent-mindedness, because mindedness isn't demanded by the cars we drive. They even talk to us now and tell us where to go.

Which, in my book, is a good thing. An automatic subconscious process is far less likely to go wrong than one which requires constant attention, and makes it easier to give that attention at the point it's needed.

 

[snorri]

If brakes have improved, then why do we need to have high friction surfaces at virtually every junction?

Because measures introduced to improve safety are regarded by drivers as measures which enhance performance.
I can well remember the glee when radial tyres were introduced to a light van fleet and drivers discovered they could go round familiar corners faster than with the old cross-ply tyres. 'These radials are like being rails' was a familiar expression at the time.

 

[ufkacbln]

Because measures introduced to improve safety are regarded by drivers as measures which enhance performance.
I can well remember the glee when radial tyres were fitted and drivers of a fleet of commercial vans discovered they could go round familiar corners faster than the with the old cross-ply tyres. 'These radials are like being rails' was a familiar expression at the time.

Yep....

Which proves the point about driving safety

You can improve safety, efficiency, engineering, and the muppets will simply drive at the edge of the new advance making it as dangerous as before

Better tyres, better brakes, and beter grip on the road, yet if you still speed up toa junction and brake at the last minute then you will not always stop in time.

 

[swansonj]

But your graph shows that there has been a significant change to risk for drivers....

Do you think you can discern a reduced risk attributable to the step change in seat belt use in 1983, as opposed to the general decline in risk with time?

I'm not going to go searching now, but my memory is there has also been a commensurate reduction in deaths of cyclists and pedestrians.

Yours is an easy hypothesis to test, and the data is easily available. If making driving safer for drivers has made it more dangerous for others, then when you divide pedestrian and cyclist deaths by billion vehicle kilometres you ought to see an upward trend. I don't think you will.

I'm all for testing hypotheses (I'm currently sitting in an EU scientific meeting in Athens where the current speaker must have mentioned "hypothesis" twenty times so far). But the test is not "has there been an increase or decrease in cycling risks over time?", the test is surely "do the statistics on cycling/pedestrian risk show any change associated with the step change in seat belt use in 1983?"

 

[StuartG]

Do you think you can discern a reduced risk attributable to the step change in seat belt use in 1983, as opposed to the general decline in risk with time?

AFAIR there was no step change. Seatbelts were introduced and then made mandatory on new cars. So it took around 10/15 years for most of the nation's car fleet to have drivers who could belt up. The usage of belts grew voluntarily prior to mandation which, in any case only applied to cars with seatbelts. Arguably Jimmy (cough) Savile did more with the clunk click campaign a decade earlier. Later auto adjustable seatbelts would become more effective than the earlier ones. We didn't suddenly go from a non-seatbelt to a seatbelt world. Or from two seats to all seats. It was much smoother than that.