Speed Limits Based On The 85th Percentile

[Panda]

...The artile claimed that the NSW Govt was using this method to raise seppding fine revenue rather than its intended purpose...

Wash your mouth out, what a horrible suggestion to make against out countrys government

Panda

[tmac450]

If speed limits are raised where would revenue from speed cameras etc be sourced?It'll never happen

My thoughts exactly

Panda

←

But we're constantly told it is done for ouw safety, not revenue raising. It shouldn't be an issue

By the way, what do they do with this money now anyway. Along with stanp duty on every car sold, GST, rego, RTA fees etc... I wonder why the RTA still say they can afford to fund better driver training.

[Panda]

85th percentile of what? How do you establish it - no speed limit for a period, and then set it at what 85% of drivers actually drove at?

They don't change the speed limit (because study has shown that the actual speed limit doesn't change the speed that drivers drive at) but they merely measure the actual speed traveled.

Read the whole article, very informative

Panda

[Panda]

homebush bay drive in sydney is a perfect example... 10% of people I see drive at 80kmh, 80% drive at 90kph, 10% at 100kph using the 85th percentile would say that the speed limit should be 90kph it is infact 80kph

Betcha there's a camera or 2 there

Panda

[Panda]

v interesting topic!

cant say im surprised at the way the 85th percentile data is used by the speed limit setters to ensure a steady stream of revenue from speed cameras..

You can wash your mouth out too

Panda

[Panda]

By the way, what do they do with this money now anyway.  Along with stanp duty on every car sold, GST, rego, RTA fees etc...  I wonder why the RTA still say they can afford to fund better driver training.

I'll research this one night shift

Panda

[Falchoon]

By the way, what do they do with this money now anyway.  Along with stanp duty on every car sold, GST, rego, RTA fees etc...  I wonder why the RTA still say they can afford to fund better driver training.

I'll research this one night shift

Panda

←

The Govt wastes it on such things as Chaplains to join schools ($90M). I think there would be far better ways to help schools with $90M rather than doing this.

Back to the subject of speed limits, I think they are set with the worst driver in the worst conditions with the worst car in mind ie a learner driver (or perhaps old Granny) in pissing down rain and fog at night in a 1953 Morris Minor with drum brakes all round and crossply tyres. To be fair to the pollies you can't have variable speed limits for different drivers for different conditions in different cars. You basically need all the traffic to be flowing along at pretty much the same rate or there would be (more) chaos. If you have someone cruising along at say 120km/h and they come up behind someone at 60km/h by the time they judge what speed the front person is doing they risk running into the back of them and might need to take dangerous evasive action to avoid a collision. Same with the slow person pulling out from a side street, it can be harder for that person to judge what speed the oncoming car is aproaching at. If the speed limit for the area is 80km/h there is a pretty good chance that the approaching car is doing around 80km/h (not guaranteed of course) and therefore easier to judge the speed of the oncoming vehicle and (in theory...) merge safely.

I agree that driver education is very important. At the moment it is far too easy to get your licence. There is no formal training required, you can be "taught" to drive by older brother/sister/friend/parent/other relative regardless of their driving skills. They may of lost their licence a dozen times for DUI, reckless driving or a swag of other offences or they may of only had their licence for a few weeks, it doesn't matter. So they are passing on their bad skills/habits to the learner driver.

Even "proper" driving school teachers need no formal qualifications AFAIK, just a roadworthy car and a drivers licence. A local driving school in my area teaches people in a WRX, not sure if this is a suitable car but I guess it's better than a 1953 Morris Minor with drum brakes all round and crossply tyres.

I reckon learner drivers should all HAVE to learn in a manual car (drive what they like after they get their licence). If they can't grasp the basic skill and co-ordination of changing gears while pushing in a clutch and decellerating than the world is a safere place without them on the road.

Learner should also attend a compulsary track day with accredited driver such as Warren Luff or John Bowe (just two examples, plenty of others around) similar to what you get when you buy a new HSV or FPV.

[Lumpen]

Learner should also attend a compulsary track day with accredited driver such as Warren Luff or John Bowe (just two examples, plenty of others around) similar to what you get when you buy a new HSV or FPV.

←

Nearest Track to me, in NSW (where I got my L's) would be somewhere down near Sydney...That'd be REAL practical

Lumpy

[replicant]

Firstly, definitions the 85th percentile is a statistical term and it represents in this case the speed that 85% of the sample were under - it other words only 15% of drivers observed in the sample exceeded the 85th percentile speed.

There are few important things to note the first is the veracity of the sample to the population - the 85th percentile applies to all vehicles and it is a sample at a certain place, certain time and with certain factors present. If you took the sample during peak hour during a long weekend on the Spit Bridge with a number of marked police cars present on the side of the road, then you are likely to get a different result than at say 2am on a Tuesday morning with a hidden camera.

Secondly, this assumes that road users are rational folk who take into account all factors such as the speed limit, traffic, surface conditions, weather, visibility and are a homogenous bunch in terms of skills, vehicles and concentration levels. Generally, they aren't and as noted in earlier posts, you have to take into account the lowest common denominator in terms of driver and vehicle.

Most folk consider the speeds noted in an advisory sign as being way too low, but if you have a fully laden truck these speeds are fairly reasonable. Likewise, if the current variety of road users including trucks, towing vehicles, learners, cyclists, P-Platers, SUV drivers and pedestrians are all going to share the road then something sensible has to be in place.

Speed differentials are really important. Following distances are generally poor in Australia and unless folk really have Schuey-esque reaction times (and judging by the number of accidents every morning they don't) then really everyone ought to slow down.

I've driven in unrestricted speed limit highways in Europe and you need to have concentration, skill at all times due to the mixture of vehicles including car carriers loping along at 160km/h in the middle lane... but you have the ability to cover 400km in little more than a couple of hours. Generally, the driving skills are superior but you have to be aware that a campervan pulling out of a slip road which is doing about 80km/h in the right lane is closing at over 30 metres per second if you are doing 200km/h in the middle lane - and you'll be upon it and past it like it was chained to a post and you were driving down the M7 in Western Sydney.

Also lane discipline is much better in Europe too...

As for the auto/manual conundrum... I'm actually an advocate of teaching folk to drive in an automatic first... get them understanding and concentrating on the road, potential hazards and traffic rather than car handling initially. Then teach them in a controlled environment, correct braking and vehicle handling techniques to avoid accidents. Then teach them to drive a manual...

I spent a lot of time in my early years driving in a Torana, with the permission of the landowners, in wet grass paddocks or gravel car parks learning the limits and beyond of adhesion of cross-ply tyres on a low grip surface, recovery techiques, cadence braking and the use of opposite lock where necessary. I learnt about weight transfer under acceleration, braking and cornering - and that you can control a car thru both hands and feet as well as the seat of your pants.

I've been fortunate to be able to fund cars that handle a lot better than the LC Torana and have better safety features but I still think that apprenticeship (as well as karting) meant I've been fortunate to possess certain skills that have proved useful.

I also think I'm a pretty crap driver too - I often drive in the 15th percentile above the 85th, at times I am overly aggressive, corner too hard on public roads for the sheer enjoyment (Mr Plod would be unhappy at the four wheel drift I do a couple of occasions in my daily commute) and probably one of those folk that holiday drivers curse as I'll ignore a freight train of cars, pick them off and get to the front of the queue and then disappear into thin air. I regularly drive recreationally and enjoy putting my car at its limits but I choose an appropriate venue and situation...

[tmac450]

Learner should also attend a compulsary track day with accredited driver such as Warren Luff or John Bowe (just two examples, plenty of others around) similar to what you get when you buy a new HSV or FPV.

←

Nearest Track to me, in NSW (where I got my L's) would be somewhere down near Sydney...That'd be REAL practical

Lumpy

←

Is the issue road safety or inconveniencing a few people. I think we need to look at the bigger picture here.