Newly installed crash barriers around objects on the M50/M4, are they installed wrong

Del2005

Sorry if this has been posed before but I did a search and couldn't find anything.


I've noticed on the M4 and M50 that they installing crash barriers around the new gantry signs. The thing is it looks to my untrained eye that they are all installed backwards. They have a solid metal post with a reflector towards the traffic flow and a gradual slope to the ground past the objects. Apologies if not described well but I can't get a pic when driving, but I've seen them on a few other roads also

Is there a reason why they have the solid part facing traffic and not the sloped part? I know cars could flip onto the road with the slope, but hitting a solid object at 120km/h can spin a car into the road and it would kill a biker outright, but I know that they don't care about bikers or they wouldn't have installed cheese grater median dividers.

Doom

Del2005 wrote: »

Sorry if this has been posed before but I did a search and couldn't find anything.


I've noticed on the M4 and M50 that they installing crash barriers around the new gantry signs. The thing is it looks to my untrained eye that they are all installed backwards. They have a solid metal post with a reflector towards the traffic flow and a gradual slope to the ground past the objects. Apologies if not described well but I can't get a pic when driving, but I've seen them on a few other roads also

Is there a reason why they have the solid part facing traffic and not the sloped part? I know cars could flip onto the road with the slope, but hitting a solid object at 120km/h can spin a car into the road and it would kill a biker outright, but I know that they don't care about bikers or they wouldn't have installed cheese grater median dividers.

Seen these on Gort bypass too and thought the same

corktina

i havent seen these but in the UK they have an energy-absorbing crumple zone at the leading end....slopey ones tending to make cars take off into orbit.

Del2005

corktina wrote: »

i havent seen these but in the UK they have an energy-absorbing crumple zone at the leading end....slopey ones tending to make cars take off into orbit.

They don't appear to have the energy adsorbing material here.

Taking off or bouncing back into traffic are just as dangerous, you're still in the middle of a high speed road.

L1011

They are installed entirely correctly and are safer than the angled "launch ramps" The front section is collapsible, and hence collapses in on its itself if crashed in to, taking the energy out of the impact.

These endings are being retrofitted to existing barriers elsewhere.

whyulittle

Have seen them newly installed on the Athlone BP as well. As has been said, it looked like they come in two parts alright.

Del2005

MYOB wrote: »

They are installed entirely correctly and are safer than the angled "launch ramps" The front section is collapsible, and hence collapses in on its itself if crashed in to, taking the energy out of the impact.

Thanks. I don't get much time to look when going past, I rather looking at the road and traffic.

Del2005

Had a look this evening, went a bit slower, spotted the crumple zone. Just a shame they didn't have the foresight to go to the ground and possibly save a bikers life.

dubhthach

Funnily enough saw a documentary on Freeway safety features last year. The Americans have been using these "Crumple zone" barriers for close on 20 years, mainly as there was a history of cars going airbourne if they hit the start of a barrier if it was sloped. Tbh I don't know why we didn't take a leaf out of their book. The original specification for Jersey barriers was speced in New Jersey back in the 1950's!

opinion guy

These are preferred over slopped barriers as the sloped ones have been known to launch cars. The blunt end with the crumple zone is supposed to be safer on average

Hoof Hearted

Maybe the installation instructions were from a country where they drive on the right.

To add, I always think the people who read the Roads forum have much more interest in road infrastructure than the actual people who are in involved in implementing the road infrastructure. Is that just human nature, when something becomes your job, it knocks the novelty out of it.

dubhthach

opinion guy wrote: »

These are preferred over slopped barriers as the sloped ones have been known to launch cars. The blunt end with the crumple zone is supposed to be safer on average

Definitely, they showed footage in the documentary where they had remote control cars crash into both varieties. Crashing remote control full size cars -- now that's my idea of a job

veryangryman

Hoof Hearted wrote: »

Maybe the installation instructions were from a country where they drive on the right.

To add, I always think the people who read the Roads forum have much more interest in road infrastructure than the actual people who are in involved in implementing the road infrastructure. Is that just human nature, when something becomes your job, it knocks the novelty out of it.

Implementation is just designing to a spec given to you in a "monkey-see monkey do" fashion.

The guys who do the specs (planners.. im not sure of their exact title) are the fall guys here.

Carawaystick

Del2005 wrote: »

Had a look this evening, went a bit slower, spotted the crumple zone. Just a shame they didn't have the foresight to go to the ground and possibly save a bikers life.

This and wire barriers gets mentioned lots regarding bikers.
Are there any data for how many bikers have been killed or injured by the barrier end or wire median seperators?

Compared to the number of motorbike incidents caused by hitting a ramped barrier or a crossover incident where there was no barrier?

L1011

Del2005 wrote: »

Had a look this evening, went a bit slower, spotted the crumple zone. Just a shame they didn't have the foresight to go to the ground and possibly save a bikers life.

There are far more non-bikers to be concerned about and the slam panel ending is far, FAR safer than the launch ramp for those.

opinion guy

Presumably being launched into the air is equally as fatal, if not more fatal for a biker as hitting a crash barrier. Trouble with being launched is you have to land somewhere.

Del2005

Carawaystick wrote: »

This and wire barriers gets mentioned lots regarding bikers.
Are there any data for how many bikers have been killed or injured by the barrier end or wire median seperators?

Compared to the number of motorbike incidents caused by hitting a ramped barrier or a crossover incident where there was no barrier?

It only takes 1 to make installation of panels pay for itself.

When I said down to the ground I meant the crumple zone not sloped. A foot wide object will be safer to hit then a few inches.

Also bikers are amongst the most vulnerable road users, it doesn't take much planning to make roads safer for us. Why when cars are getting safer for their occupants don't they bother designing road furniture for the most vulnerable motorway/road users?