The road toll is our fault

In G-S's defence, in my previous car (mazda 626), I would be quite
fatigued after only an hour behind the wheel at 100. At 110 (eg Newell
Hwy), I would last a couple of hours. I find in my commodore I don't
get nearly as fatigued as I used to in the Mazda, but I still find that
about 2 hours at 100 is getting toward my limit. At 110, I can
comfortably go 4 hours and be less fatigued than I would have been from
2 hours at 100. It's just something about driving at 100 - whether it is
the frequency of road noise, the speed the scenery goes by at, or if it
is just that it takes more effort to maintain the car at a near constant
100 than 110, I'm not sure. I also find that at 110, my foot is in a
more comfortable position, even if it is ever so slightly different to 100.

 

Sounds like candidates for falling asleep to me.

 

But then I also suspect sedans cause a lot more road damage too, there's 20
of them for every 4x4.

 

It's a bloody good arguement for legalising 44" balloon like mud tyres on
4x4's

 

Does tyre pressure affect the pressure exerted on the road somehow, 2 tonne
is 2 tonne, whether it's sitting on 4 tyres at 15psi or 55psi. Contact patch
size changes but does that really matter when you compare frictional wear to
point contact wear?

I run 55psi on my 255/85's but mates run 30psi in thei 285/65's

Our Triton work ute, 185/75's must destroy the road by being at 40psi?

 

Or course a 2 tonne vehicle will always exert 2 tonne on the road,
irrespective of tyre pressure. However tyre pressure alters the area in
contact with the ground. 2000lb car with 20psi tyres has 100sq-in of
tyre area on the ground. Inflate the tyres to 40psi and it drops to
50sq-in that is in contact with the ground. Close enough anyway. Other
factors such as sidewall strength and tread pattern will alter this
slightly. If you don't believe me, watch what happens when you inflate
or deflate your tyres - at high pressure, they lift and less touches the
road, at low pressure they are all squishy and more is touching the road.

Someone posted that 4WD's do more road damage, and someone else said
they couldn't because of their greater surface area on the road. Yes
they have a greater surface area, but that surface area is exerting
greater pressure. Clearly however there is more to the equation than
just the pressure exerted on the road. If that was all there is to it,
then my pushbike with it's 90psi tyres would be leaving chewed up
bitumen everywhere I go. Road damage is really a function of total
weight, speed, and shearing forces (acceleration, braking, cornering,
friction caused by the not-perfect rolling action of tyres etc), not
just PSI.
If you still don't believe me that pressure on the road matches tyre
pressure, try this simple test. Put your finger on the road, and have
someone run over it in a falcadore with low tyres. Then have someone run
over it on a pushbike. The pushbike will hurt a hell of a lot more. If
you don't want to go to those extremes, experiment with a garden hose on
concrete. You'll find that the water flow drops much more with your
pushbike than with one tyre of a car on it. You could even try inflating
a tyre while it is parked on the hose and watch what happens to the
water flow.

They exert more pressure per square inch, but that alone is not likely
to cause road damage.

 

"I live in Cairns, and the roads here are certainly not good, get out of the
city and you will find corrugations in the bitumen, pot holes and generally
narrow bad roads, out west it is worse. Many of the roads out there have
only single car bitumen, and when there is a car coming the other way or you
want to pass, it is onto the dirt on the side of the road.

Riding a motorcycle you get jarred from the bad roads all the time.

In parts where there should be no problems, and the limit is 100 Kmh there
is no way you can do that sort of speed because of the conditions of the
road.

A few months ago I went up onto Cape York (The Tip) in a 4 wheel drive. The
trip had 800 Km of dirt road to get up there from Cairns.

Of that there was 160 Km of horror stretch, where you were reduced to first
and second gear driving for long periods. There were washaways both across
the road and running down the road, some of these were sharp trenches 300 mm
deep, hit one that run across the road at any sort of speed and you could
rip out your suspension. It took over 4 hours to negotiate that 160 Km of
road, did I mention that in some parts there were trees down blocking 3/4 of
the road?


The locals tell us that the grader has not been up there for 2 years !!!

Where does all our fuel tax go Mr Howard?

Every time I hear about the road toll, it is always drivers (and riders) at
fault, never our lousy road system.

How many Governments have promised to "Fix" the Hume Hwy, and the Pacific
Hwy, and yet we still have death stretches on them.

Anyone noticed what a fine smooth road there is running between Canberra and
Sydney?

 

So now I'm really confused does my 2 tonne 4x4 do more road adamage at 20
psi or 50psi?
Personally I don't think it matters SFA and I don't think a 2 tonne 4x4
causes more damage than a 2 tonne Falcodore or 4x 500kg Festiva's.
These are roads designed to handle 30-60? tonne Semi trailers.

 

Actually, I'd be inclined to think it'd do more damage at 20psi - only
because at such a low pressure the tyre would have more rolling friction
and would be producing greater shear forces on the road. Realistically
though, it's gonna be bugger all. In a light vehicle, unless you do
stupid things like burnouts, you are unlikely to do significant damage
to the road surface.

Personally, I think you are right. The weight difference between
Festivas, Falcadores & 4x4's is still pretty minimal compared to Semi
Trailers. The much higher weight of a loaded truck (even if the PSI
exerted is less than a pushbike) causes far greater damage.
Additionally, the use of dual and triple axle designs causes
considerable stresses on the road surface when these vehicles are
turning. I've actually seen bitumen being torn up beneath the wheels of
a truck doing a tight turn. Obviously the bitumen must have been in poor
condition to begin with, but in a tight turn the wheels are being pushed
sideways across the bitumen, instead of rolling.

 

And yet we have those here claiming domestic 4WD's are destorying all the
roads , LOL.

 

Nooo
never
12- 14 hours a day isn't long is it?

spent 4 years doing loads that take at least 7 hours and up to 14
hours:-Brisbane-Wandoan-Brisbane, 12 hours:-Brisbane-Miles-Brisbane,
Brisbane-Jandowie-Brisbane, 7 hours:- Brisbane-Dalby_Brisbane,
Brisbane-Maryborough-Brisbane, Brisbane-Brookstead-Brisbane,
Brisbane-Millmerrin-Brisbane

DOH

Kev

 

but again if you have trouble driving at 100 without falling asleep then

That was kinda my point

 

How many accidents are caused by people falling asleep at the wheel?

If you're driving a truck, weighing in at a dickbag of tonnes, then you dont
have much choice BUT stick to 100kph, do you. Damn limiters. Unless of
course you were bypassing yours, which is illegal and naughty Feeling
bitter at all the cars that over took you and got the trip done half an hour
faster?

 

I get paid by the hour
not in my best interest to bypass the limiter


Like I said

I can drive all day long at 100 and not get tired or drowsy
(unless I haven't had anough sleep before I start work)

And not just in the truck either
I've done plenty of long distance drives in my cars and still manage to
stay alert at 100kph

Kev

 

I can't take both hands off the wheel... and even if I did I might not
see that emu when I was so distracted


G-S

 

At some speed point that happens... but it isn't 120 to 130... it would
be somewhere around 140 to 150.

I have a 15 minute work commute


G-S

 

There is a difference between people 'claiming' it and people for whom it is
actually true, and I haven't seen anyone here claiming they were safer
at 250!

Now I know you don't know me from a bar of soap, but I would never claim
250 (or even 150) was safer on our roads than 100... and I haven't made
such an unreasonable claim.

I was speaking only about my experiences, and I have never tried to
claim that other people won't experience different physiological
responses, in fact I went out of my way to mention that fact.


G-S

 

Stopping distance isn't what we were discussing though.

I freely admit stopping distances at higher speeds are longer.

The question is does the increasing risk of falling asleep at 100
outweight the other risks or not... and honestly I don't know the answer
to that.

As is obvious by this thread _not_ everyone can do it. You shouldn't
assume that because you can do something that everyone can... that is a
simple mistake many often make.

People are differnt and they have different skills, skill levels and
responses to stimuli which leads logically to a differing safe speed for
each person.

The problem with the blanket speed limit is that it assumes that people
are not different when in fact they are.


G-S

 

That may be your's, but what you have to realise is for the average driver
(soccer mum, city driver, 45yo) it may be a lot less.

For me 110 is fine, 130 may seem fine for the first hours, with some fast
music going, but then I have to have a break.

Well an extra 20kph isn't going to make much difference to you, much as the
50kph zones in stead have 60 have made bugger all difference to my 5 minute
commute.

 

No, but there are people who because their car can do so, use it as an
excuse to do so, imagine what speeds the average 19yo male would be driving
at in their performance cars, given Toby's stupid arbitrary blanket
derestricted limits.
Sorta like some idiot bikes in traffic using the "if I move fast enough,
they won't hit me" theory.