Russell-

Thanks for posting this.  I was beginning to think that I was the only one
who had considered these points and things along these lines.

I personally feel that there should be 100% passive speeding detection
checkpoints every few hundred feet, everywhere.  A mailbox with 200
tickets after a trip to visit the family would certainly apply the brakes to
those who feel no obligation to obey posted speed limits, and at much
less cost than the corpse of a child.

Basically, I have weighed the options and decided not to risk it.

And now an anecdote...I live in Iowa, Central US, and a prominent
politician in a neighboring state recently struck and killed a motorcyclist
because he was speeding and ran a stop sign.

The man fell apart.  I never saw him that he wasn't weeping.  He
resigned from Congress and is currently serving his penance (I don't
think he got any jail time).  His life is ruined, and I think it's less than
he deserves.

There are numerous records of him saying "If I'm willing to pay the
fine, why shouldn't I speed?"  The man he killed wasn't willing to
pay, nor was his family, but they paying they are.

Look, the long and the short of it is this:  kinetic energy increases
as the square of velocity.  IF you wreck, or hit someone, or
whatever, the difference between 25 whatevers/h and 26
whatevers/h is the difference in scaling KE by 625 or 676.

Let's not even get started on the mass element and what that
shiny new Hummer H2 is going to do to my little car...

Mike H.

>I feel a moralistic rave coming on.
>But not one without good engineering foundation.
>Fasten your seatbelts, set your cruise controls, we're off ....
>
>After just having suggested offlist to one poster that he may be treading
>on
>politically shaky ground (not that I care, it's not my stooge he was
>talking
>about :-) ) , I'll
>turn to a so far unproscribed area and add my 2 cents worth :-)
>
>I often hear people waxing lyrical over the inequity of speed cameras, red
>light cameras, traffic radar and traffic police in general. I do wonder
>what
>such people (and there is of course a range of opinions) would feel
>genuinely comfortable and happy with? No traffic rules? No speed limits*? -
>or perhaps limits but no enforcement. Maybe limits with very wide
>enforcement margins. (50 mph with 30 mph margin = typically 90 mph in
>town).
>I also wonder what they would do that they don't do now to protect their
>children under such utopian arrangements.
>
>I note that there seems to be a correlation between speed capacity of
>vehicle and probability of radar detectors being fitted. I am aware, of
>course, that radar detectors are fitted by responsible drivers to improve
>the safety of their driving (I just haven't worked out how that works yet).
>I note that a more recent safety improvement is the fitting of GPS and
>waypoint memory to radar detectors so that the driving may be even safer
>again - and I also so far have not been able to muster the intellect
>required to understand the no doubt simple mechanism by which this works.
>
>Social contract (whatever that may mean in this age) says that we give
>ourselves certain rights to kill a certain percentage of ourselves in
>exchange for the rights to expect a certain level of protection from
>ourselves. It's not as if there is some external authority who we are
>trying
>to beat. We are dealing with ourselves. The whole basis for the engineering
>of our environment stands on the social contract we have set ourselves. How
>clean the air, how fast the cars, how good or how often the safety checks,
>how polluted the food or how uncertain we are of what we are ingesting is
>set
>by ourselves. (We know that Mon$anto and their ilk will try and bend the
>rules at every turn in some of these areas, but lets stick to road safety
>in
>this diatribe.)
>
>If we all, or a clear majority, feel that the limits we have set are too
>restrictive, then we have the right and ability (in most countries at
>least)
>to stand up
>and say so and do something about it. If we think that more children should
>die on city streets so that we can get home sooner, or if we think that
>changing our driving behaviour won't change how many children die, or if we
>think that enforcement mechanisms are inefficient or wrongly targeted,
>then we have the right and the ability to do something about it. If we
>think
>we'd rather have arguably safe nuclear power and leave the problems to our
>children's children in place of unquestionably
>unsafe coal power which gives us problems now then we have a right to do
>something about it.
>
>If instead we simply do what we wish, or attempt to, or wish to then we are
>stealing, attempting to steal or wishing to steal the benefit of the agreed
>social contract from ourselves - or from the portion of ourselves who
>don't.
>If we ALL do this then it's just money in the government's coffers, and
>SOMEBODY has to fund us, so who cares. (Less government-ers, tax is
>theft-ers, enclave isolationists and others**  may stand up and be counted
>here :-) ). And of course, more dead children all round, but if we all do
>it
>then we have just modified the social contract and we're all happy.
>
>The major problem is, that the child struck by the car which
>would have been able to stop if it had been travelling at
>agreed-social-contract mph, or the person broadsided by the "why shouldn't
>I run late orange was-that-REALLY-red-officer? lights if I want to"
>free-thinker is usually not the person who has bought into the social
>contract initially. Each year the US kills more of its citizens in road
>"accidents" than died in the whole Vietnam war, over 10 time as many as
>died
>in "911" and far far more than will die in Afghanistan & Iraq, no matter
>how
>many more
>that may yet be. (43,000 auto fatalities USA 2003, almost 3,000,000
>injuries.)
>   (NHTSA early assessment for 2003 - interesting)
>   (    http://www-nrd.nhtsa.dot.gov/pdf/nrd-30/NCSA/PPT/2003EARelease.pdf
>)
>
>But, my constitutional rights, it's only done to fill government coffers,
>everyone does it, radar
>detectors for safety,...  & more mean that's not liable to reduce
>appreciably
>anytime soon.
>
>For a little perspective, the US death rate per car is less than for France
>and half as much as Portugal's. For a bit more perspective, the death rate
>per capita (a more real measure) is worse than for France but not quite as
>bad as Portugal or Greece. I suppose one could be proud of having a better
>death record than Greece. Or Portugal. (Have you ever seen spectators at a
>Portugese rally ? :-) !!!! ).
>US fatalities per capita which are 2.5 times a high as UK suggests (only
>suggests) that the
>unreasonably strict tolerances on speeds on their motorways and their
>obnoxious bobbies MAY just be doing something. So the USAites can laugh,
>NZ's record is slightly WORSE per capita than the USA's.
>_______________
>
>Few people (even engineers) seem to appreciate how much more damage a car
>travelling only "slightly" faster will typically do to a pedestrian.
>
>Fatality rate (McMahon empirical formula) is approx
>
>% killed = V^2/5000%     V in kph or
>% killed = V^2/1800%     V in mph.
>
>Above 100% death is essentially certain.
>eg at 50 kph %death = 50^2/5000 = 50%
>at 70 kph =~ 100%
>
>A car travelling at 70 kph will kill about 50% of the ball chasing children
>that the same car travelling at 50 kph just manages to stop for.
>
>A car travelling at 60 kph will kill over 20% of the ball chasing children
>that the same car travelling at 50 kph just manages to stop for.
>
>What may not be intuitively obvious without having thought about it (even
>to
>engineers) but which is obvious on reflection, is that if two identical
>vehicles, which have a speed difference of V mph, start braking together,
>then
>when the slower one stops, the faster one will be still travelling at MORE
>than V mph. Possibly much more. This is because the energy in the vehicle
>accumulates with the square of the speed and the extra speed adds
>substantially more than linear energy. As an example, two cars travelling
>at
>70 & 50 kph start braking together. Assume that the brakes can remove
>energy
>  at a constant rate. In practice brake fade etc may make this assumption
>invalid - which leads to a worse result. Car A at 50 kph has 50^2 = 2500
>units of energy. Car B at 70 kph has 70^2 = 4900 units of energy. When car
>A
>has just stopped car B has (4900-2500) = 2400 units of energy left so is
>travelling at sqrt(2400) = 48+ kph (!!!!). ie A 70 kph car will hit at
>about
>50 kph an object that a 50 kph car can just stop for !!!!. Reaction time
>makes this worse as during reaction time car B travels further so has less
>distance to brake in.
>
>As covered in more detail below -
>
>     Car A CANNOT kill the child which it just fails to hit.
>     Car B will kill the child about 50% of the time.
>
>There are some assumptions that vary the end result eg reaction time,
>whether the car can decelerate at constant g or at constant energy
>reduction
>rate or .... . Whatever the assumptions - if a 50 kph car JUST stops a 70
>kph car will hit at around 50 kph - maybe more.
>(Constant energy reduction should be a reasonable assumption. Unless you
>are
>at maximum coefficient of friction point then brakes should be working as
>hard as they can which should be a constant rate until they begin to fade.
>At brake locking point the best that can be achieved is about 1g (depends
>on
>car) so that could also be used as a best case assumption).
>
>At 50 kph impact you kill 50^2/5000 = 50%
>Hey - that's not so bad. 50% odd live!
>But every dead child is one outside social contract. If you ever kill one
>in
>such circumstances you should feel (as you are) responsible for the rest of
>your life. There are, of course, ways to feel better about this.
>Should have looked first, parents didn' bring them up to take care, they
>KNOW people drive fast through here, they shouldn't have been allowed to
>play with a ball on such a busy street, my car had superb performance and
>excellent brakes and my reaction times are so swish hot that an ordinary
>car/driver would have killed them anyway,... .
>
>The social contract, as currently implemented, assumes that all drivers and
>vehicles are equal. It gives good drivers and good vehicles a chance to
>improve the safety of others. I would not like to bet that "good" drivers
>with "good" cars only equal out the equation when they decide to make
>themselves as dangerous as the average car/driver. The velocity^2 energy
>rule brings the BMW into normal territory faster than most would realise.
>(if YOU dispute this - do YOU believe the analysis above that says that 50%
>of people that YOU would have just missed will die if YOU are doing 70
>rather than 50?.)(If not, explain why).
>
>Have I ever hit a person while driving a motor vehicle? Yes and no - I'd
>laid the motorcycle on the road by the time I hit the running child - and I
>wasn't speeding. And they weren't severely hurt. Still doesn't feel very
>nice (for them or me :-) ).
>Do I sometimes exceed posted speed limits? yes. Run the occasional red
>light? - er,
>yes. Make excuses for why I do it? No. It's indefensible.
>Is it safe enough? - often, yes. Aren't there occasions when the posted
>limits don't make sense? - yes, BUT when they don't make sense and then an
>"accident" happens, it's no accident. But of course there are lots of
>explanations.
>How was I to know that there would be a kid there at that time in a
>weekend?! - this place is ALWAYS deserted in weekends !!!
>Who would have thought that anyone would have been coming through that
>intersection at that time of night?
>Hey! - I drive a BMW/Mustang/Lamborghini/Unimog :-) / Have been driving for
>60 years/have a clean
>record / am a Mason (where'd that come from) ...
>
>Dead. My little girl is dead!? What happened???
>Rerun above excuses.
>
>And I wonder how many who feel utterly frustrated by tightly controlled
>speed limits (like our British brethren seem to) have worked out how much
>difference it actually makes to trip time to travel at say 100 kph versus
>120 kph.  Or around town at 50 vs 60 or 70.
>
>In Arizona I'm told that people cruise at 100 mph plus. Didn't see any. May
>have been due to the spotter aircraft signs ?
>
>But, I did like the autobahns * :-)
>
>
>             Russell McMahon
>             (who really hopes he won't now go & do something stupid in a
>car
>and kill anyone  in the next while)
>
>
>_______________________________
>
>For a NZ article that explains that increased speed does NOT result in more
>deaths, see
>
>         http://www.investigatemagazine.com/july00speed.htm
>:-)
>
>______________
>
>* In Germany on the autobahns there are indeed no speed limits. And it all
>looked and felt very safe. When we were there last year, cruising at 130 -
>140 kph (80-90 mph) we had people passing us at 100+ kph deltas (!). Sit in
>the outside lane more than a few seconds too long at 130 kph and you have
>a Mercedes glued on your rear bumper until you pull into the "slow" lane.
>While there are no speed limits, there are definitely rules AND everyone
>seems to abide by them. The roads are built to suit. When they do have
>accidents, and of course they do, the probably have less problems with
>getting people to hospital than we do here. Elsewhere in Germany there are
>very strictly controlled speed limits - some quite conservative. Heavy
>vehicles have their limits for each class of road displayed prominently on
>the back so authorities can see at a glance whether they are doing as they
>are intended to.
>
>** I thought about saying "... other whingers ..." there, but I'll leave it
>to the footnote readers to decide if that was wise :-) .
>
>*** Congratulations if you got this far :-)
>
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