Wire barriers good or bad ?

Forums › Transport (cars, bikes and boats) › Wire barriers good or bad ?

1 | 2 | 3

pdath

252 posts

Ultimate Geek

#1388344 16-Sep-2015 07:51

One of the leading road safety experts in our geographic area is Monash University in Australia. They did a good investigation into the issue:
http://monash.edu.au/miri/research/reports/atsb201.pdf
To the best of my knowledge, NZ has not implemented any of the recommendations that would make wire rope barriers substantially safer for motorcyclists. Until then the wire rope barriers will continue to dismember motorcyclists who are unlucky enough to crash into them.

Try my latest project, a Cisco type 5 enable secret password cracker written in javascript!

pdath

252 posts

Ultimate Geek

#1388345 16-Sep-2015 07:55

surfisup1000: So the last time a motorcyclist died on these wire barriers was 2007? How frequently does it occur?

It not just deaths. Its motorcyclists getting arms, legs, and hands cut off by the wire rope.

How much extra do solid barriers cost over wired?

Its been a while since I looked into this. I think there is an additional 20% to 30% initial capital expense, but they require a lot less maintenance so the solid barriers work out cheaper over the course of their life time.

How many km of road have these 'wire' barriers?

Don't know.

How much more effective would a solid barrier be over a wire barrier for motorcyclists? Seems to me that usually an accident at the legal limit would often result in motorcyclists death anyway.

The problem is wire rope barriers cut though body parts. The solid barriers tend to just break bones but don't tend to kill. 6 months after a serious accident you will be much better off if you came into contact with a concrete barrier than a wire rope barrier.

What is the price of a life?

I think the current number is about $2 million when used for making decisions. The number gets reassessed every now and then.

Try my latest project, a Cisco type 5 enable secret password cracker written in javascript!

pdath

252 posts

Ultimate Geek

#1388347 16-Sep-2015 07:59

Geektastic: I seem to recall reading many years ago a complaint from a motorcycle group in the UK where the median barriers are usually solid Armco barrier that if they came off and slid, they would connect with the uprights which are visible below the lower edge of the barrier panel in a gap.

From their pov, no barrier that did not extent down to meet the road surface was good enough.

That is correct. What has happening is they only put the bar on the top, and motorcyclists would slide underneath hitting the solid post. The fix was very easy. They now install a lower bar which stops the motorcyclist sliding under, and hence they can't hit the post any more.

NZ never adopted this method either.

Try my latest project, a Cisco type 5 enable secret password cracker written in javascript!

pdath

252 posts

Ultimate Geek

#1388348 16-Sep-2015 08:04

...
It was only a presentation summary. There is a plethora of studies around the world on crash barriers. It is important to differentiate between the speculative hype and facts, and the facts do not support the 'cheese-cutter' outcomes claimed by the motorcycle lobby. There is also a cost involved. If every road in NZ was 'perfect' the country would be broke.

If you want more reasoning this explains in quite well http://www.reaaa.co.nz/publication/cheesecutters-eggslicers-and-motorcycles-by-nicholas-rodger-transit-nz/wppa_open/

I have picked up more dead bodies from the side of the road that I care to remember. I am also a lifetime motorcyclist. I still believe the wire rope barriers have more positives than negatives.

I posted a couple of posts earlier an extensive study done by Monash university in Australia, a well respected road safety research institute. Care to post any research by someone as respectable that supports your view? The link to an "article" posted by a Government body that is trying to support a decision they have already made is hardly compelling.

Try my latest project, a Cisco type 5 enable secret password cracker written in javascript!

k14

629 posts

Ultimate Geek

#1388392 16-Sep-2015 09:27

Mark:
throbb: Don't the stats speak for themselves? 29 serious injuries or deaths in the 10 years before they were installed and zero in the 10 years after.

Where are those stats from ? And kind of forgets the poor dude who got killed on a wire barrier in 2007.

Missing from the article is the fact that he was speeding whilst doing a wheelie (at 3am in the morning) and then when he landed the wheelie his frame broke. Not sure if it was ever proven but the theory was his frame was fatigued from him doing so many wheelies and that caused it to break. Maybe he was would have died even if there wasn't a WRB there. I know the guy he was riding with at the time.

Journeyman

1186 posts

Uber Geek

#1388642 16-Sep-2015 17:20

Engineers like wire rope barriers. They absorb more energy than concrete barriers, though I suspect that applies more to cars than motorcycles. Thing is, if you come off your motorcycle on a motorway, you're going to have a bad day no matter what you hit.

pdath

252 posts

Ultimate Geek

#1388644 16-Sep-2015 17:23

Journeyman: Engineers like wire rope barriers. They absorb more energy than concrete barriers, though I suspect that applies more to cars than motorcycles. Thing is, if you come off your motorcycle on a motorway, you're going to have a bad day no matter what you hit.

I doubt they absorb more energy because there mass is much less. However they certainly deform more.

If I came off on my bike I would much rather break some broken bones than have my head or a limb cut off.

Try my latest project, a Cisco type 5 enable secret password cracker written in javascript!

Equinox IT

Cloud spending continues to surge globally, but most organisations haven’t made the changes necessary to maximise the value and cost-efficiency benefits of their cloud investments. Download the whitepaper From Overspend to Advantage now.

Sideface

9349 posts

Uber Geek

Trusted

Lifetime subscriber

#1388654 16-Sep-2015 18:08

Journeyman: Engineers like wire rope barriers. They absorb more energy than concrete barriers, though I suspect that applies more to cars than motorcycles. Thing is, if you come off your motorcycle on a motorway, you're going to have a bad day no matter what you hit.

+1

Executive Summary:

Wire barriers are good for cars.
Nothing helps motorcyclists.

Sideface

9349 posts

Uber Geek

Trusted

Lifetime subscriber

#1388655 16-Sep-2015 18:10

pdath: ... I doubt they absorb more energy because there mass is much less. However they certainly deform more. ...

They absorb more energy because they deform more.

Sideface

mdooher

Hmm, what to write...
1424 posts

Uber Geek

ID Verified

Trusted

Lifetime subscriber

#1388660 16-Sep-2015 18:21

Sideface:
pdath: ... I doubt they absorb more energy because there mass is much less. However they certainly deform more. ...

They absorb more energy because they deform more.

When a motorcyclist hits a concrete barrier he normally hits at an acute angle and slides along the barrier. The energy transfer happens slowly as his leather heats up and wears down. When hitting a cheese cutter he is stopped by the post and the deformation of the wire is insufficient to slow down the energy transfer sufficiently to make it survivable. He may survive if the kinetic energy is used in the separation of a couple of limbs though.

Matthew

Journeyman

1186 posts

Uber Geek

#1388663 16-Sep-2015 18:35

pdath:
Journeyman: Engineers like wire rope barriers. They absorb more energy than concrete barriers, though I suspect that applies more to cars than motorcycles. Thing is, if you come off your motorcycle on a motorway, you're going to have a bad day no matter what you hit.

I doubt they absorb more energy because there mass is much less. However they certainly deform more.

If I came off on my bike I would much rather break some broken bones than have my head or a limb cut off.

Maybe I should've mentioned my source - my brother is a transport engineer. There's the deformation, as others have mentioned, and - as I understand it - the energy is spread along a length of the rope.

With a concrete barrier, it doesn't deform and it doesn't move much from its base. It's not a lot different from slamming into a brick wall.

scuwp

3885 posts

Uber Geek

#1388673 16-Sep-2015 19:25

pdath:
...
It was only a presentation summary. There is a plethora of studies around the world on crash barriers. It is important to differentiate between the speculative hype and facts, and the facts do not support the 'cheese-cutter' outcomes claimed by the motorcycle lobby. There is also a cost involved. If every road in NZ was 'perfect' the country would be broke.

If you want more reasoning this explains in quite well http://www.reaaa.co.nz/publication/cheesecutters-eggslicers-and-motorcycles-by-nicholas-rodger-transit-nz/wppa_open/

I have picked up more dead bodies from the side of the road that I care to remember. I am also a lifetime motorcyclist. I still believe the wire rope barriers have more positives than negatives.

I posted a couple of posts earlier an extensive study done by Monash university in Australia, a well respected road safety research institute. Care to post any research by someone as respectable that supports your view? The link to an "article" posted by a Government body that is trying to support a decision they have already made is hardly compelling.

Sorry but hardly consider it 'extensive'. It basically outlines the lack of research (which I agree with) and attempts to set up some parameters for recommended testing to get funding for same. Other than recommendations around testing there were no conclusions whatsoever.

I posted the NZTA presentation as there seemed to be a misunderstanding of the 'logic' behind the decision to install wire rope barriers. I thought that may help. It wasn't meant to be a impartial definitive study.

Sorry I no longer have access to the SAE research database, I have let my subscription lapse since leaving the field. Suffice it to say that I agree with the above authors who identified the lack of empirical studies on this risk.

I have no doubt that if a motorcyclist hits a WRB it is going to hurt...a lot! But my own real world experience of 20+ years backed up by national statistics does not support the 'cheeze-cutter' hyperbole that keeps getting spouted out. The crash stats the show this doesn't happen is used to bolster the installation decisions around WRB.

Lazy is such an ugly word, I prefer to call it selective participation

1 | 2 | 3