Road Dividers

[grigor]

Any thoughts on these tensioned cable-on-post road dividers?

Queensland Transport has fallen in love with these things but I don’t like them at all.

I saw the tests done by the Swedes a few years back but there are items they missed.

Obvious one is bikes. Poor buggers may as well dive into razor wire.

The most serious one is maintenance, or the lack of.

In early December, a new section of road South of Gympie was opened using this divider. Within days it had been hit 2-times by South-bound vehicles. At least 20 posts bent in that direction and the wire sagged.

So what happens if a North-bound vehicle spears into these nicely angled arrows? And what use this sagging wire that might just come up to your sill.

It’s almost February, it hasn’t been repaired and what a job to fix. All that cable will be suspect so it must be replaced.

This particular design has the cable twisted between alternate posts. I saw the guys trying to finish it and they had crowbars, jacks the lot to get the final bit installed.

There are numerous designs, some with 4-wires, others have 5 and not all the designs use this twisted cable idea.

I can see the budget quickly disappearing in maintenance rather than in decent pavement.

[1C3B3RG]

I don't like them either. Guys on motorcycles would be chopped up badly on impact. Also once they are hit, they are difficult to repair. I reckon it's another example of some dude sitting on his throne and approving a paper proposal. That said, the traffic management and raod management in Queensland is so crap. I have been around the world and have to say i still get frustrated by stupid designs.

My latest pet hate is when maintenance workers put signs on the motorway 80Kph then 60 then 40. So we obey them, traffic nearly grinds to a halt and guess what? No roadworks, signs been left out for a week after work was finished!

No wonder most people only slow down for them if they see blue and red flashing lights in the distance.

[dangerous_daveo]

They arent actually that bad. The idea is to stop the 'bounce' of your hard armco ones. Bikes are a minority unfortuneate as that sounds, thats no doubt how its worked out.

Either way, whats your suggestion? Your stuffed on a bike at 100kmh anyway, they cant put big airbags in everywhere.

Dont take it as being defensive, Id like to know what other systems are about.

[grigor]

Like I said at the start, I saw the overseas tests regarding "bounce", but that argument falls over if the divider has a 1-impact life, which is the case for any I've seen.

For a central road divider, I like concrete. The bounce tests I saw weren't a glancing blow but rather at an impact angle of approx 40degrees. In this situation, the wires certainly grab and slow the vehicle instead firing it off at a tangent. But for a very acute angled impact, the vehicle just gets torn to bits.

For kerb side protection, nothing wrong with Armco.

Can you imagine the carnage if Bathurst was ringed with this stuff instead of Armco.

As for the unfortunate bikers, it's obvious they were simply forgotten.

Don't get me started on the signs.

[dangerous_daveo]

Yeah, like a bike hitting concrete is going to 'hurt' same with an armco. I guess with an armco and the wires there is a chance of sliding under it.

You got the links to any of this stuff?

Like I guess the main thing is teach people how to drive so they dont hit them in the first place, but thats too logical.

[grigor]

Like I guess the main thing is teach people how to drive so they don't hit them in the first place, but thats too logical.

EXACTLY.

[mystery_kid]

My latest pet hate is when maintenance workers put signs on the motorway 80Kph then 60 then 40. So we obey them, traffic nearly grinds to a halt and guess what? No roadworks, signs been left out for a week after work was finished!

yeah thats annoying, but not the workers fault

it's the the guy in charge of overseeing the construction, could be an engineer etc

traffic signs and control are done by a seperate section/company

[r33cruiser]

i just saw a crash into one 2 weeks ago on my way back from goldie. a little hatch back had put the front right bar into the steel rope fence.

the damage wasnt too bad,,, it was drivable. it look like the wire had SLOWED down her car while she was against it. btw, the fence was still standing.

so i think theyre a good thing. but on a head on impact i wouldn't like to be in the car. the fences look like they could easily decapitate u.

so on a head on=bad

on grazes and brushes=good

Edited January 31, 2008 by r33cruiser

[Jdfnq]

These things pretty much = death for a biker....

they aren't so bad for cars actually...

Better and safer than armco and that's why they are being used.... Have you seen the damage that armco can do to a car (and it's passengers) if you hit it the wrong way?????

either of them is better than hitting another car or going off a cliff

[bloodzkull]

yep pretty much a death sentace for someone on a bike.

and as of friday the section of road just south of gympie still wasn't repaird.

it's a simple case of someone looking at the costs to install. and the wire works out cheaper.

[trism]

any sort of crash at a decent speed is death sentence for bikers. and they know these risks when they start riding a bike....

[1C3B3RG]

yep pretty much a death sentace for someone on a bike.

and as of friday the section of road just south of gympie still wasn't repaird.

it's a simple case of someone looking at the costs to install. and the wire works out cheaper.

Yes that is true, but would you as a biker want to die as a bag of mince ( smashed up corpse inside tight leathers), or many pieces like lamb chops?

[dangerous_daveo]

Yes that is true, but would you as a biker want to die as a bag of mince ( smashed up corpse inside tight leathers), or many pieces like lamb chops?

Really, I wouldnt care. I would be dead.

[psi]

I have a big problem with the wires for 2 reasons..

1: there is no divider to keep the wires the same distance apart during an impact because they tear out of their retaining posts. Check out the really long sections near gympie! They will easilly tear your car apart when they spread, or worse.

2:Serious lack of maintaince. If they have already been strained, what good are they next time? do u reuse conrod bolts?

I have seen a proto type similar to that of armco that flattens to conform to the vehicle shape on impact. It is mounted onto collapseable bars about 500mm long before they inturn are mounted to a post in the ground. Once again, anything that deforms its own shape is going to soften the blow, but it has to be maintained. If you crash harder than the rail will deform, you will be caught by the posts.