Bob
This discussion topic has developed into a very interesting debate.
Australia certainly is unique and has many good reasons to apply a
different approach to problems. However it is my understanding that
the Australian horse is roughly the same size as the Canadian and
therefore I would expect the horsepower calculations to be similar.
For the 14 volt and 8 amp current figures you have selected, the HP
estimate of 1/2 is too high by a factor of about 3. HP= (volt x amp x
eff)/748
As you say it is important to separate the safety benefit attributed
to a certain action from the costs. However it is equally important
to examine ways of reducing the costs to make the safety initiative
viable. For example, taking you point about power consumption as
stated, there may be a case for the development of low power diode
lights for use in DRL applications. They have been used by the
bicycle industry for years now with good success. Could this be a
practical technology for DRL needs?
John Woodrooffe
-----Original Message-----
From: The list is for the use of academics and others interested in
technical, op [mailto:[log in to unmask]]On
Behalf
Of IS Edit
Sent: Tuesday, September 10, 2002 3:38 AM
To: [log in to unmask]
Subject: **SPAM** Re: Daytime running lights
Hi Robert and Phillip.
The case has not been clearly made for daytime running lights in
Australia.
And regulation is not always the answer.
There is the problem that DRLs suitable for use in dull climates
(which
often have darker vegetation than most of Australia) might not be
effective
under Australian (for instance) conditions.
There is the issue that hot filaments are less durable than cold
filaments
and anyone that thinks that is not worthy of consideration has not
spent
much time on Australian roads (rough).
On a 14 volt system it takes about 8 amps just to run headlights (if
they
were to be the ones to use in a bright, light coloured landscape).
That uses
up about 1/2 horsepower.
Figuring about 125,000 litres per year fuel consumption for a
reasonable
longhaul truck in Australia, daytime running lights (assuming the
truck is
running during the day) would cost somewhere around $250 per year in
fuel.
That's about 1/4 of one percent of fuel at 100kmh which is where
trucks
cruise in most of Australia. Heavy vehicles are a small percentage of
the
total number of vehicles on the road but they have high exposure and
use a
lot of fuel.
And by nature they are conspicuous in the first place.
We don't need to argue that a car is more easily seen with lights on,
but we
need to quantify cost and benefit to see if it is worth imposing yet
another
regulation and another requirement on motorists and commercial vehicle
operators. If such a move requires a Regulatory Impact Statement,
you'll
have to prove it is cost effective, anyway.
Your sarcasm about putting yet another shilling in the electric meter
cracks
me up (did you used to live in Earl's Court, too?). I haven't seen too
many
academics or regulators yet (or anyone else either) with a good
batting
average for getting another shilling or two out of government
treasuries for
roads and infrastructure improvements in the interests of public
safety.
It seems some of them spend an inordinate amount of time imposing or
trying
to impose additional requirements on vehicle operators to achieve
safety
gains because it is too hard to get governments to return sufficient
funding
from road taxes of various sorts for maintenance and improvements.
Regulation isn't the universal panacea, either. The US FMVSS121 and
its
premature imposition of anti-lock brakes comes to mind, as does the
Australian regulation specifying a certain 7 pin trailer connector for
heavy
vehicles that was designed for car utility trailers and which had a
rated
capacity less than half of that required for many combination vehicles
common on Australian roads. Seems Australian regulators when
specifying the
connector chose what the Europeans call a 12 volt plug (meaning a car
plug
because all their trucks are 24 volt) because most of our big trucks
being
US technology based have 12 volt systems. Uh huh.
Where, pray tell is common sense really common, Phillip? I haven't
found
that place in 56 years.
I spoke up because this old DRL issue has been around more times than
a
Melbourne tram and I still haven't seen any convincing argument in
favour
for Australia. Because I did so colourfully, it got a response, some
of them
very illuminating (pun intended).
Much more and we would beat it to death.
Cheers,
Bob Murphy
----- Original Message -----
From: "Robert A. Douglas" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, September 10, 2002 11:34 AM
Subject: Re: Daytime running lights
> I cannot believe the amount of email traffic this has generated.
Why is
so much being
> made from this? Clearly, with lights on, a vehicle is more easily
seen,
even in daylight.
> We need to argue this? And what is the problem with having them on,
are
people afraid
> they'll have to put another shilling in the electric meter or
something?
>
> The ONLY sensible complaint I've heard about cars running with
headlights
on during
> the day is that it makes MOTORCYCLES (which typically run with
lights on)
somewhat
> less visible themselves.
>
> R.A. Douglas
>
> Robert A. Douglas, BASc(CE), PhD, PEng
> Senior Lecturer, Director of Studies (Forest Engineering)
> geotranz - Natural Resources Geotechnique
> and Transportation Engineering
> New Zealand School of Forestry
> University of Canterbury
> Private Bag 4800
> Christchurch, New Zealand
> tel +64-3-364 2117
> fax +64-3-364 2124
> http://www.fore.canterbury.ac.nz/
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