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Speed camera's on Northern Ring Rd, Melbourne

Started by LX2DR , Oct 24 2006 12:10 AM

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44 replies to this topic

#26 MRLXSS

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Posted 25 October 2006 - 12:52 PM

Perhaps next time you want to challenge what I post, do some research....then maybe you wont need to challenge it at all

Did my research, i have actaully driven both these cars. Maybe not at the speed difference of 150 and 80. say 100kmph compared to 80kmph. The mercedes has a superior brake package and superior tyres.

With your calculations just show that a mercedes travelling at 150kph will stop faster than a mercedes stopping at 80kmph. because You have not taken into consideration at all that the mercedes brakes work a hell of a lot better than the Hq brakes. You have said that "The merc, lets give it real sticky tyres, deaccel at 0.9g," What about the Hq? i say it stops at about 0.5g. And just using that little calculator the mercedes shit all over the hq.

Its not just the brakes and tyres that make the merc stop so fast, its all the sway bars motion sensors ans shit that make the car firmly stick to the road. the weight is evenly balanced through braking so all four wheels can get the best contact with the road.

Anyway u would have to agree that a mercedes going 90 will stop alot faster than a hq doing 80. Even if you had peter brock behind the wheel of the hq he couldn't get it to pull up any faster.

So why do the Speed cameras go to town on someone breaking the speed limit by 3kmph? there are so many variables that relate to the stopping ability of the car that 3kmph isnt going to achieve much..

And on this point i have never got a speeding fine, or any fine from driving offences. I do the speed limit and respect the law. Been pulled over once in the hq and that was just cos he wanted to see what engine was in it.

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#27 _devilsadvocate_

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Posted 25 October 2006 - 02:16 PM

No one is disputing that mercedes brakes are better than a HQ, just the margin that you believe them to be, why quote numbers like the merc wil stop better from 150 than the HQ from 80 when you really have no idea at all.
0.5g for a HQ, isnt good enough......0.7g is obtainable by a HQ at suburban speeds, given the tyres are up to it. For some time the vic royal auto measured the stopping dist of every car it tested from 100kmh, every car I remember reading about(for the last 35 years ) was able to stop in less than 50m with whatever tyre it was equipped with, that equates to 0.77g.
If we take your 80kmh HQ and the 90kmh merc with values of 0.7 and 0.9g deaccel the stopping distances are basically the same, however, when we add driver reaction distances the merc will need another 3metres.
At speeds of 150kmh, the simulator will give you a number, but what happens in reality......there is brake fade and the high braking effect of just the air to throw in as well,which the simulator knows nothing about for the mercedes or HQ. Id predict that the mercedes number would behave more to theory given that its brakes would not be subject to the same degree of fade as the HQ.

Its not just the brakes and tyres that make the merc stop so fast, its all the sway bars motion sensors ans shit that make the car firmly stick to the road. the weight is evenly balanced through braking so all four wheels can get the best contact with the road.

There are some measures that can be taken to reduce the forward pitch of the car, however, the only way to get balanced four wheel braking under deacceleration is to have the car's centre of mass at axle height, like in a formula one car.
Why have the tolerances so tight? Most people work out over time where 60kmh is on their speedo and do the tolerance above that. When the tolerance was 6kmh or whatever it was, just meant that the traffic flowed at that amount above the speed limit, which was considered to be faster than intended. The line has to be drawn somewhere and perhaps the penny still hasnt dropped for some that the limit is 60kmh, not the suggested speed. It has to be the same rule for all cars, having the courts clogged up with, "but I just put grippier tyres on the front....I should be able to go 2kmh faster" isnt going to cut it.
One way around it would be to make the limit lower and give back a higher tolerance, ie 55kmh with a 6kmh tolerance. This would then create a problem with a higher speed differential between those that feel obliged not to exceed 55 and those that use up all the tolerance and travel at 61kmh. I dont think we need to have this dilemma just to satifsy minority looking for any flimsy excuse to get out of their fine etc. Zero tolerance is fine for me.

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#28 _devilsadvocate_

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Posted 25 October 2006 - 02:45 PM

With your calculations just show that a mercedes travelling at 150kph will stop faster than a mercedes stopping at 80kmph. because You have not taken into consideration at all that the mercedes brakes work a hell of a lot better than the Hq brakes.

Sorry to harp on, but no, my figures compare the mercedes at 150 with a hq at 80. using 0.7g for the HQ, how did you figure that I hadnt or did you assume I must have made some basic mistake?, check the figs again........carefully

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#29 _JBird_

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Posted 25 October 2006 - 03:01 PM

Peter UC and LX2DR hit the nail on the head.

I think speed cameras are affective in lowering road tolls...if they were placed EVERYWHERE to enforce a 50km/h speed limit. YEAH RIGHT. In Sydney the most notorious revenue raising camera is around the rockdale area near a school. It's located on one of the main roads (don't know road names just know directions) but at certain times enforces at 40km/h speed limit - on a main road. Another few are also just as useless. Why put a speed camera on a straight stretch of road without any conceivable danger in sight? It'd be understandable if they put speed cameras before every corner of some twisty roads like old pac but it makes no sense having speed cameras on straight stretches of roads. Increasing their (the cameras) effectiveness in reducing speeding (one of the many factors of road fatalities - lets be serious the faster your travelling when you hit something the more likely your going to be dead) would be better locations. At the moment the speed cameras encountered by many aren't in "black spots", they put them at the bottom of hills to catch you at the mercy of gravity etc.

Where aren't driver training courses mandatory or subsidised? As part of the Logbook rule for L platers they should dedicate like 10 hours of the 50 hours your meant to do to driver training courses. RE: the 24% drop that drop was seen within a couple of months of the courses/skid pan/tracks opening. Whats more interesting is ever since the draconian high performance car ban for P platers road fatalities for young drivers hasn't decreased at all, but actually increased.

Just to add, because of the recent tragic deaths of those 4 guys - the government is going to look like they're doing something about this "young driver problem" with another band aid approach, enforcing a P-plater passenger restriction. Probably increasing the logbook hours to 100hours as well - piss off. Most kids do 20 hours and make up the rest. At least if they do that the government could make sure they did 10 or more hours of driver training (like motorbike license holders have to do). The last time they mucked around with P-plater bans was because a GTR skyline split in half (his dads car took it for a joyride to 200km). Bandaid: stop new pplaters from driving them. All fixed if you have 23 dollars and a willing constructiong business to provide a reference that you need a hi-po vehicle for work..

*Gets off soap box*

Edited by JBird, 25 October 2006 - 03:09 PM.

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#30 _MAWLER_

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Posted 25 October 2006 - 03:06 PM

To use PeterUC's example of the wipe off 5 add, there are two ways you can look at the logic. Wipe off 5 and you are able to slow down enough to only brake her hip, speed up to 80 and you're way past the footpath before she even gets there to step out onto the road, :tease:

Its just a joke BTW fellas, before someone takes it as an example of the poor attitude of blah blah blah

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#31 _JBird_

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Posted 25 October 2006 - 03:10 PM

To use PeterUC's example of the wipe off 5 add, there are two ways you can look at the logic. Wipe off 5 and you are able to slow down enough to only brake her hip, speed up to 80 and you're way past the footpath before she even gets there to step out onto the road,

Its just a joke BTW fellas, before someone takes it as an example of the poor attitude of blah blah blah

What are WOMEN doing on the roads anyway :tease:

(Tinkers IT WAS A JOKE! I dont want to take a holiday!)

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#32 _devilsadvocate_

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Posted 25 October 2006 - 03:25 PM

Why put a speed camera on a straight stretch of road without any conceivable danger in sight? It'd be understandable if they put speed cameras before every corner of some twisty roads like old pac but it makes no sense having speed cameras on straight stretches of roads.

I did put a good point forward(I think so) for this in an earlier post, but Ill try again:
If people know where they are going to be...like on corners, they wont speed there.....which is good, but they will speed everywhere else. If they know they are never going to be put on straight stretches of road then there will be "some" who do excessive speeds here, causing trouble for everyone.

At the moment the speed cameras encountered by many aren't in "black spots", they put them at the bottom of hills to catch you at the mercy of gravity etc.

Two things here:
1. People claim they didnt realise their car gained speed going down the hill, if you dont realise you are going downhill how much attention are you paying Another observation Ive made, people compensate with more accelerator when going uphill with no problems at all. :blink:

2. Going faster down a hill reduces your ability to stop in two ways:
a. the higher speed attained(which should be obvious)
and not so obvious
b. the reduction in the effective braking force which occurs with the decrease in friction between the road and tyres with increasing angle
c. the force of gravity pushing the car down the hill.
A 5 degree angle will result in a 10% increase in stopping dist at the same speed as on level ground(for the average tyre), throw in going 70 rather than 60 as well and the difference increases by 36% again.
Really, lower limits going down hill would make more sense.......disregarding them is ludicrous.

Edited by devilsadvocate, 25 October 2006 - 03:34 PM.

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#33 makka

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Posted 25 October 2006 - 03:48 PM

anyway, BACK ON TOPIC,
they are also fitting redlight/speed cameras to the intersection of Chapel St and Alexandra Av at the moment

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#34 LC69GTR

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Posted 25 October 2006 - 03:54 PM

Yeah they need them with there 40k speed limit lucky if you can do 10k up chapel on a sat night :rockon:

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#35 makka

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Posted 25 October 2006 - 03:56 PM

they are right up the other end, at the yarra river, I reckon they will get a fair few going along Alexandra Av.

I know what you mean about the traffic! :banghead:

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#36 LX2DR

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Posted 25 October 2006 - 05:43 PM

Yeah they need them with there 40k speed limit lucky if you can do 10k up chapel on a sat night

I see nothing wrong with speed cams around school crossings; little kids are unpredicable & can dart out from anywhere.

As too the wipe 5 ad! it is just an ad!!!!! And has probably been enhanced for visual impact.

If she turned the Ipod down a little she would have heard the car coming? If she had looked left & right before she stepped out she would have seen the car, but this is all hypothetical as it is just an ad, and only one senario, earlier or later will have a huge impact on the end result.

It�s not always the fault of the car, the driver or the speed, pedestrians should pay more attention as well, they are putting themselves in harms way! Cars are hard immovable/moving objects & it will hurt.

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#37 _torana06_

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Posted 25 October 2006 - 05:56 PM

they are revenue raises but maybe they can but the millions of dollars they get into learner driver courses and making country and some metro roads safer.

i hate copping more cameras on perfectly safe places it bullCR*p

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#38 _CHOPPER_

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Posted 25 October 2006 - 07:09 PM

........did you know that for a truck to be legal it only needs to be able to deaccelerate at ~0.2-3g......good argument that they should travel a lot slower than cars.

By your comment, I take it you don't have a heavy vehicle license. If taught correctly ( some driving schools don't ), you learn to drive a heavy vehicle so you don't need to use the brakes until you have slowed down to 20 KPH.

Don't know if anybody else has noticed it, but on the back of some tankers is a big sign saying:

At 60 KPH, this vehicle needs 100 metres to stop SAFELY. Please allow...blah, blah, blah.

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#39 _devilsadvocate_

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Posted 25 October 2006 - 08:35 PM

By your comment, I take it y
ou don't have a heavy vehicle license.

I dont know how you could assume I have or haven't by me referring to the req braking performance of heavy vehicles.............

you learn to drive a heavy vehicle so you don't need to use the brakes until you have slowed down to 20 KPH.

Must have missed that one.........we are talking about stopping the vehicle in as short a distance as possible in this thread which should require brakes at whatever speed we are going?

Edited by devilsadvocate, 25 October 2006 - 08:40 PM.

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#40 RIM-010

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Posted 25 October 2006 - 08:43 PM

DA, you ever driven a manual? You can slow down pretty effectively, pretty quickly, by downchanging...

RIM

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#41 _devilsadvocate_

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Posted 25 October 2006 - 08:58 PM

Goodness gracious ^

Things have changed since I started to drive. Havent got into a new car recently......I take it manuals dont come with brakes anymore?
Really never found that just using the gearbox on a heavy vehicle slowed it down enough going down mountain passes......exhaust brakes help though.....

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#42 _DocDamage_

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Posted 25 October 2006 - 09:58 PM

DA is only talking about the legal requirement and he is right. Due to the increased mass of a truck, traction between tyre and road surface becomes the issue. More brake pessure will make the wheel turn slower but the mass is too great for the tyres and they will skid. No need to legally require it to do more than the contact patch can handle.

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#43 _devilsadvocate_

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Posted 26 October 2006 - 09:27 AM

While driving through a 40kmh school zone this morning the vehicle in front of me suddenly pulled over, uniformed officer quickly got out moved to left side of car and set himself up with a radar gun. I was looking at all this in the rear view, before Id gone another 150m down the road he had his first "satisfied" customer.......magnificent work officer :spoton:

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#44 LX2DR

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Posted 26 October 2006 - 10:07 AM

While driving through a 40kmh school zone this morning the vehicle in front of me suddenly pulled over, uniformed officer quickly got out moved to left side of car and set himself up with a radar gun. I was looking at all this in the rear view, before Id gone another 150m down the road he had his first "satisfied" customer.......magnificent work officer

As i said school zones are perfectly legitimate spots for cameras and radar.
For once i agree with you! :clap: