Just something I'm curious about...
I assume we've all seen the impact attenuators they put in front of
concrete highway dividers and toll booths - the barrels of sand or
large rubber bumbers. They're supposed to slow a vehicle down so they
don't hit the solid obstruction at full speed.
Why do they mark them with orange cones after they get damaged?
Are they trying to tell drivers not to hit them because they won't
they provide the anticipated protection?
As far as I know, drivers don't typically have the option of choosing
where to have an accident. If we were able to avoid the impact
attenuators when they are marked with cones, don't you think we'd
avoid them at all times?
What's the point of marking them with "caution cones" when no one
would actually consider hitting them even if they weren't damaged?
They are not barrels of sand, but barrels of water. They mark
them for a couple of reasons. One to indicate damage to the
safety devices and to help prepare regular commuters for future
repair crews which will come to replace them. The notice to
drivers is mostly a CYA for the governing authority.
Number two is that at certain times, someone MAY HAVE to choose
where to have an accident. Being one who drags trailers around
in the course of my work and working with some heavy equipment,
if the choice is between hitting the little old lady, the school
bus, or the collision barrels, I will choose the barrels. Unless
they are damaged. Brakes fail and other problems occur which can
make you have to choose.
re: They are not barrels of sand, but barrels of water
I guess it depends on where you drive.
As per this site, none of the devices approved for permanent
installation use water, but one does use sand. Temp ones (e.g.
construction sites) are allowed to use water.
A doc found at an Ilinois site (http://www.wsdot.wa.gov/EESC/Design /
Policy/RoadsideSafety/Chapter720/sand.htm) also mentions sand filled
attenuators - granted it's 2006 doc, but the Washington site appears
to be current.
The ones I've seen damaged (and marked with cones) were messy piles of
plastic and sand.
Anyway, you mentioned that given the choice, you'd hit an unmarked
barrier rather than an old lady, so I'll accept that as a valid reason
for marking them. I certainly hope you never have to make that choice
- especially if it's marked with cones.
re: They are not barrels of sand, but barrels of water.
As per this wa.gov site, none of the attenuators approved for
permanent installations use water but one does use sand. Temp ones may
This doc from Illinois also mentions sand filled attenuators:
The ones I've seen damaged and marked were always piles of sand and
plastic. Maybe the water dried up. :-)
Anyway, your mention of making the choice the between an old lady and
the attenuators makes sense. I certainly hope you never have to make
that choice, and if you do, I hope the attenuator isn't marked by
cones. I'd feel real sorry for the old lady.
I work for our state's DOT, during the winter. I set out plenty of barrels,
when not keeping the xways free of snow & ice. Our barrels are empty, we
place a dual rubber base to keep it in place. By hand, you can move these
where ever you please. They are not meant to slow down a vehicle veering
out of control.
It's a liability thing on the State's part. Being the crash attenuator is
no longer functional, it must be marked. It relieves the state from
liability from someone claiming the state put potential hazard in their
If you look at any potential hazards in your State, chances are, they are
marked. That is, unless the marking has become defaced. A call to your
controlling authority, being local or DOT, will get the hazard
fixed.....ASAP. This is not to say exit sign posts are to be marked,
because they already use reflective letters or backing. Also, the post must
be able to bend or shear, or both.
Two years ago, in different district than ours, they had piled snow in
front of the exit signs, which are placed in the Gore (the triangle area
between the roadway and exit). They had rain, then freeze. What they ended
up with, was a giant ramp, which a vehicle had launched off of, when they
missed the exit ramp. The state settled out of court on this, since the
state had placed a hazard within their right-of-way.
here, the yellow ones are partially filled with sand, in two layers, one
at bottom, and one in an inner lid. Water freezes and leaks. The just
need to have enough mass so wind doesn't blow them around, and to create
enough friction to break the contact patch between the skidding car and
the ground. They may be ugly, but they work a lot better than the
telescoping sections of armco rail, which tend to rust together. (They
used to bury the rail approaches to avoid spearing people, until they
realized that just provided a launching ramp for a keen stunt driver
For awhile around here, they also went back to wood posts for the signs,
predrilled to break in a certain way when hit, and corkscrew over the
car instead of going through windshield. I guess they weren't durable
enough- they seem to have gone back to metal the last few years.
I guess I should have _snipped_ the part about yellow barrels. I was
replying to the part about the _orange cones_ being set out after an
attenuator gets damaged. Instead of orange cones, we set out orange
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