Cycle helmets - major study

Tony Raven said:

Gonzalez <[email hidden]> wrote:

Quoted message said:

Quoted message said:

Who would you rather travel as a passenger with: a tired driver hacking down the motorway at 95
mph, or a tired driver cruising down the motorway at 65 mph.

Quoted message said:

The former because the journey will be over with quicker. A crash is going to hurt some at either
speed so I'll go for the shorter exposure time ;-)

That's one factor... Which driver is more likely to fall asleep per unit time?
--
Paul Smith Scotland, UK safespeed.org.uksafespeed.org.ukOpen ↗ please remove "XYZ" to reply by email speed
cameras cost lives

Mohammed Saeed Al-Smith said:

The best place to look for elevated inattention is where we've forced a driver to travel at a speed
significantly slower than the one he judges to be safe. He's bored and disinterested in his task.

Ah, yes, the driver decides that it's definitely safe to go much faster than he's allowed so the
driver decides he need not pay attention and kills someone. The hallmark of good and competent
drivers everywhere, obviously. The observed fact that most drivers overestimate their own skills is
not, of course, to be taken into account.

Sadly this kind of crass idiocy is now enshrined in road "safety" policy to the extent that the
Government's official remedy for SMIDSYs is to encourage their victims to drive more carefully.

Frankly anybody commuting by car is bored and disinterested most of the time anyway. I can't think
of anybody I know who commutes by car who regards it as anything other than a monumental pain in the
[censored]. They should try cycling - much more stimulating.

Guy
===
** WARNING ** This posting may contain traces of irony. chapmancentral.comchapmancentral.comOpen ↗ (BT ADSL and
dynamic DNS permitting)
NOTE: BT Openworld have now blocked port 25 (without notice), so old mail addresses may no longer
work. Apologies.

Gonzalez said:

I have frequently driven at 30 in lane 3 of a motorway, especially the M6 around Birmingham.

You lucky [censored]! I can't remember the last time I saw it move that fast!

Guy
===
** WARNING ** This posting may contain traces of irony. chapmancentral.comchapmancentral.comOpen ↗ (BT ADSL and
dynamic DNS permitting)
NOTE: BT Openworld have now blocked port 25 (without notice), so old mail addresses may no longer
work. Apologies.

Mohammed Saeed Al-Smith said:

It's extremely likely that the tired 65mph driver could improve his safety and alertness by
speeding up to 95mph, as long as to do so was within normal safety margins (i.e. vision, traffic,
capability etc).

Not half as much as he could improve his safety (and that of all those around him) by pulling off at
the next opportunity and sleeping for 15 minutes, rather than ploughing on and hoping he didn't
become another Gary Hart.

And any driving instructor, advanced or otherwise, who doesn't agree with this is incompetent.

Guy
===
** WARNING ** This posting may contain traces of irony. chapmancentral.comchapmancentral.comOpen ↗ (BT ADSL and
dynamic DNS permitting)
NOTE: BT Openworld have now blocked port 25 (without notice), so old mail addresses may no longer
work. Apologies.

you know? said:

Quoted message said:

It's extremely likely that the tired 65mph driver could improve his safety and alertness by
speeding up to 95mph, as long as to do so was within normal safety margins (i.e. vision, traffic,
capability etc).

Quoted message said:

Not half as much as he could improve his safety (and that of all those around him) by pulling off
at the next opportunity and sleeping for 15 minutes, rather than ploughing on and hoping he didn't
become another Gary Hart.

Tiredness is somewhat relative isn't it? It's perfectly OK to drive when tired, but we all must stop
before we are too tired.

Quoted message said:

And any driving instructor, advanced or otherwise, who doesn't agree with this is incompetent.

I couldn't agree more except that tiredness isn't absolute.
--
Paul Smith Scotland, UK safespeed.org.uksafespeed.org.ukOpen ↗ please remove "XYZ" to reply by email speed
cameras cost lives

you know? said:

Quoted message said:

Unnecessarily slow speeds become dangerous when they are soporific or when the means of reducing
speed distracts drivers or otherwise reduces their concentration or distorts their priorities.

Quoted message said:

Luckily, 30mph (and lower) speed limits around towns are completely necessary, and amply justified
by an examination of the probabilities of death when pedestrians are hit at various speeds. So
that's all right then.

30mph speed limits are amply justified on some roads, especially town roads.

But that doesn't tell us that lowering speed limits or increasing enforcement will make the
roads safer.

As far as pedestrian impacts are concerned it's quite clear from an examination of the facts that
impacts at free travelling speeds are rare, and we should be looking at the factors which already
mitigate 99%+ of such impacts and their severity to find further improvements.
--
Paul Smith Scotland, UK safespeed.org.uksafespeed.org.ukOpen ↗ please remove "XYZ" to reply by email speed
cameras cost lives

Quoted message said:

Quoted message said:

My experience playing rugby tells me that as soon as I start

breathing

Quoted message said:

Quoted message said:

hard, my mental capacity diminishes.

Quoted message said:

You are confusing two effects: mental capacity dimishes *as you start playing rugby* <gd&r>

Quoted message said:

Guy
===

Oh. I thought you were going to say mental capacity must be diminished BEFORE one decides to
play rugby.

Paul Smith said:

The Italian Government agrees and has recently raised the motorway speed limit "to improve
alertness".

So all those overhead gantry signs have got it wrong...

Instead of saying, "don't drive tired, take a break", they should say, "Feeling tired? Then
speed up!"
--
remove remove to reply

Gonzalez said:

Quoted message said:

The Italian Government agrees and has recently raised the motorway speed limit "to improve
alertness".

Quoted message said:

So all those overhead gantry signs have got it wrong...

Quoted message said:

Instead of saying, "don't drive tired, take a break", they should say, "Feeling tired? Then
speed up!"

30% of accidents on some UK motorways are believed to be sleep related. I would have thought that a
proper basket of measures would be appropriate. Nevertheless I don't think it's sound advice to
speed up if you feel tired.

On the other hand, driving at a decent speed suitable for the conditions may delay the onset of
significant tiredness. This could well be a valuable lifesaver.
--
Paul Smith Scotland, UK safespeed.org.uksafespeed.org.ukOpen ↗ please remove "XYZ" to reply by email speed
cameras cost lives

Paul Smith <[email hidden]> wrote in :"]news:[email hidden]:

Quoted message said:

On the other hand, driving at a decent speed suitable for the conditions may delay the onset of
significant tiredness. This could well be a valuable lifesaver.

We've heard some real bull [censored] from you so many times, but this takes top marks! Do us all a
favour, when you're next due to fall asleep, go out an get some hard evidence for us. Drive at 90mph
along a deserted road and see if it wakes you up. You might get woken up by the sudden adrenaline
rush just as you realise you're headed for a tree, but you'll at least have the satisfaction of
knowing you're right.

Graeme said:

Paul Smith <[email hidden]> wrote in :"]news:[email hidden]:

Quoted message said:

Quoted message said:

On the other hand, driving at a decent speed suitable for the conditions may delay the onset of
significant tiredness. This could well be a valuable lifesaver.

Quoted message said:

We've heard some real bull [censored] from you so many times, but this takes top marks! Do us all a
favour, when you're next due to fall asleep, go out an get some hard evidence for us. Drive at
90mph along a deserted road and see if it wakes you up. You might get woken up by the sudden
adrenaline rush just as you realise you're headed for a tree, but you'll at least have the
satisfaction of knowing you're right.

There's no need to attack me because you don't have a clue.
--
Paul Smith Scotland, UK safespeed.org.uksafespeed.org.ukOpen ↗ please remove "XYZ" to reply by email speed
cameras cost lives

Graeme said:

We've heard some real bull [censored] from you so many times, but this takes top marks! Do us all a
favour, when you're next due to fall asleep, go out an get some hard evidence for us. Drive at
90mph along a deserted road and see if it wakes you up. You might get woken up by the sudden
adrenaline rush just as you realise you're headed for a tree, but you'll at least have the
satisfaction of knowing you're right.

I know its not the acceptable thing to agree with anything Paul says in this newsgroup but I'm going
to stick my neck out. I used to travel a lot internationally so two to four times a month I was
dealing with significant jet lag from 6-12hour time shifts. I found the best way of dealing with it
was to keep myself busy during the normal day wherever I was. As long as I was mentally occupied I
could function quite normally and wouldn't feel tired although my judgement and attention span was
not up to scratch for which I made a concious allowance. The moment there was a lull in proceedings
the tiredness would catch up with me and I would struggle not to take a nap.

I am absolutely certain from personal experience that mental concentration can ward off the effects
of tiredness very effectively and its backed up by research. NASA have a team (the Fatigue
Countermeasures Group or "Z team" ) who specifically study this particularly for flight operations.
An interesting quote from the US Navy Flight Surgeons Manual chapter on fatigue says "Interesting
tasks with relatively simple motor skills are resistant for periods as long as 60 hours, but routine
monotonous tasks show a rapid decrement after 18 hours without sleep."

So while I don't agree with driving tired, it is much better if you are doing a challenging task for
a shorter time than a boring one for the same time or longer if you are going to be doing it.

Incidentally there is a factor in the airline industry called "sleep inertia" which is the first 30
mins after being woken are equally risky while you transition from sleep to fully awake. If you are
going to nap keep it short (<45 mins) because once you get into deep sleep, sleep inertia will add
to your problems for 30 mins after you wake. I always allow a good 30 mins in the morning between
getting up and driving.

Tony

Robert Goodman said:

The last time I played I was propping and in the 2nd half the ref didn't like the way we were
forming scrums, so he said he'd have us touch & engage on his call. I said, yeah, sure, and then as
we crouched he said, "Touch" maybe 3 times before I realized, "Dummy, he's talking to YOU!" I was
just staring at my immediate opponent waiting for something to happen. I'm sure that wouldn't've
happened if I had a cool head.

I'm trying to keep an open mind about forwards, especially front row ones. ;-))

James

--
homepage.ntlworld.comLarrau.jpgOpen ↗

Robert Goodman said:

Oh. I thought you were going to say mental capacity must be diminished BEFORE one decides to
play rugby.

Beat me to it, Robert.

James

--
homepage.ntlworld.comLarrau.jpgOpen ↗

Robert Goodman said:

Well, yeah, that's probably because you were good!

Not particularly. However, I also used to ski and, thinking about, my brain did used to feel the way
you describe when you were playing in your rugby matches.

FWIW, I was a far better skier than I ever was a rugby player.

James

--
homepage.ntlworld.comLarrau.jpgOpen ↗

Paul Smith <[email hidden]> wrote in :"]news:[email hidden]:

Quoted message said:

There's no need to attack me because you don't have a clue.

I'm attacking you because a) for some reason my killfile seems to have let you slip past and b)
whilst some people may find your contributions mildly entertaining I am one of the many who find
them tedious, generally based on dubious claims and almost entirely unrelated to the subject of
this newsgroup, i.e. cycling. However the main reason is c) you come across as an irritating
little pillock who doesn't have the wit to be able to contribute on anything other than his own
pet subject.

Back in the killfile you go, hopefully you'll stay there and hopefully you won't provoke others into
trying to talk some sense into you. There seems little point.

Graeme

Paul Smith said:

There's no need to attack me because you don't have a clue.

I think they are attacking you because *you* don't have a clue. Subtle difference, I know, but...

Guy
===
** WARNING ** This posting may contain traces of irony. chapmancentral.comchapmancentral.comOpen ↗ (BT ADSL and
dynamic DNS permitting)
NOTE: BT Openworld have now blocked port 25 (without notice), so old mail addresses may no longer
work. Apologies.

Paul Smith said:

Quoted message said:

Quoted message said:

It's extremely likely that the tired 65mph driver could improve his safety and alertness by
speeding up to 95mph, as long as to do so was within normal safety margins (i.e. vision, traffic,
capability etc).

Quoted message said:

Quoted message said:

Not half as much as he could improve his safety (and that of all those around him) by pulling off
at the next opportunity and sleeping for 15 minutes, rather than ploughing on and hoping he didn't
become another Gary Hart.

Quoted message said:

Tiredness is somewhat relative isn't it? It's perfectly OK to drive when tired, but we all must
stop before we are too tired.

Tiredness sufficient to make it difficult to concentrate when driving legally is excessive and
should be dealt with by stopping for a rest of some sort. That much is an absolute.

Guy
===
** WARNING ** This posting may contain traces of irony. chapmancentral.comchapmancentral.comOpen ↗ (BT ADSL and
dynamic DNS permitting)
NOTE: BT Openworld have now blocked port 25 (without notice), so old mail addresses may no longer
work. Apologies.

Paul Smith said:

30mph speed limits are amply justified on some roads, especially town roads. But that doesn't tell
us that lowering speed limits or increasing enforcement will make the roads safer.

No, the figures from areas where average speeds have been reduced do that perfectly well.

Quoted message said:

As far as pedestrian impacts are concerned it's quite clear from an examination of the facts that
impacts at free travelling speeds are rare,

Did you learn nothing from the argument about the Joksch equations? Energy is proportional to speed
squared, so the ability to stop, or at least to reduce speed sufficiently to avoid fatality, is
significantly affected by the initial speed.

Quoted message said:

and we should be looking at the factors which already mitigate 99%+ of such impacts and their
severity to find further improvements.

Instead of apologising for speeders and the terminally clusless, and forcing their victims to take
extra measures to protect themselves. Quite.

Guy
===
** WARNING ** This posting may contain traces of irony. chapmancentral.comchapmancentral.comOpen ↗ (BT ADSL and
dynamic DNS permitting)
NOTE: BT Openworld have now blocked port 25 (without notice), so old mail addresses may no longer
work. Apologies.

Paul Smith said:

Unnecessarily slow speeds become dangerous when they are soporific

Nothing is soporific if one is not tired. Therefore your statement should be translated into "If you
are tired then the excitement of travelling fast may keep you from falling asleep."

--
Chris Malcolm [email hidden] +44 (0)131 650 3085 School of Artificial Intelligence, Division of
Informatics Edinburgh University, 5 Forrest Hill, Edinburgh, EH1 2QL, UK
[dai.ed.ac.ukcamOpen ↗ ] DoD #205