Median Cable Guardrails-good or bad?

[Terry Shea]

http://www.michigan.gov/mdot/0,1607,7-151--222435--,00.html
What do you think?  Personally I hate them.  They're ugly and I doubt they're going to save lives.  In fact I'm pretty certain they'll end up killing more people than they'll save.  What happens when a motorcyclist hits a cable at high speed?  Severed limbs?  Decapitation?  What happens when the cable snaps and goes through a vehicle and/or a body in the vehicle?  Most vehicles that go into the median aren't going to cross all the way over into oncoming traffic.  Now this same scenario creates the increased risk of bouncing off the barrier and back into traffic every single time a car leaves the inside lane, not crossing all the way over the median into oncoming traffic once in a blue moon.

And here in the wintertime cars end up in the median during bad weather quite frequently.  It was no big deal before, you simply had to get towed out.  Now each instance is going to cause severe damage to their vehicles along with the risk of being thrown back into traffic, during hazardous conditions no less.  I think insurance rates are going to skyrocket and they're already way too high.  I think this was a total waste of $40 Million on MDOT's part and I think they were quite irresponsible in implementing this w/o gathering all the facts and/or getting everyone's input.

[agentsteel53]

the ones that get shredded are the ones that are going fast enough that they'd have entered the opposite lanes of traffic and gotten smashed anyway.  better they expire without bringing other vehicles into their own mess.  

want to not get cut to ribbons in the median?  stay out of the median.  

(try drinking less.)

[tchafe1978]

Wisconsin had been installing these along many freeway medians in response to numerous cross-over crashes. I would be in favor of them if they save lives.

[Terry Shea]

the ones that get shredded are the ones that are going fast enough that they'd have entered the opposite lanes of traffic and gotten smashed anyway.  better they expire without bringing other vehicles into their own mess. 

want to not get cut to ribbons in the median?  stay out of the median. 

(try drinking less.)

You missed the point completely.  This is going to cause more vehicles to become involved in more accidents.  Probably well more than 99% of the vehicles entering the median stay in the median and don't cross into oncoming traffic.  Now every single vehicle that would have simply gone into the median unscathed otherwise, is going to be extensively damaged and is going to be bounced back into traffic out of control.  They may have tire damage, they may very well be on slippery roads and they may very well end up going into oncoming traffic in the wrong direction anyway.  Check out the video on the MDOT page!  Check out the van that was supposedly saved from going across the median into oncoming traffic.  Now they don't know that the van would have crossed all the way over the median, but look where the van is located!  It's on its roof and it crossed 2 lanes of traffic!  That doesn't sound like a very safe scenario to me.

And obviously you're not used to driving in Michigan in the wintertime with winter storms, freezing rain, blizzards and what have you.  Cars are going to go into the median and they'd simply need to get towed out.  Now they're going to to incur damage and will become a hazard to other vehicles when the re-enter the freeway out of control...and quite possibly on their roof like the van in the video.

[agentsteel53]

a car that, in the absence of the cable, ends up in the median and stops is going to be a car that drifts harmlessly into the new cable.  The cars that get shredded are the cars that would go screaming into opposite-direction traffic.  Honestly, I'd rather have one car shredded than two.

as for cars that are bouncing back - they will remain traveling forward with respect to the direction of traffic that they intersect, as opposed to backward (much higher relative velocity at time of collision!) if they go into the opposite direction traffic.

it's a lot easier to avoid a car skidding at 50mph away from you than skidding at 50mph towards you.

[Terry Shea]

Not only is the van in the video upside down, it's also facing the wrong way. 

[Terry Shea]

it's a lot easier to avoid a car skidding at 50mph away from you than skidding at 50mph towards you.

It's impossible to avoid a car coming at you from the side or across your path.  But yeah, let's cause 99% more accidents by eliminating 1% of the accidents.

[agentsteel53]

Not only is the van in the video upside down, it's also facing the wrong way.  

that it is.  And, regardless of its orientation, what direction was it traveling in before it came to a stop?  To turn a van around is trivial.  To turn around its direction of motion is difficult proportional to its initial velocity.

[agentsteel53]

It's impossible to avoid a car coming at you from the side or across your path.  But yeah, let's cause 99% more accidents by eliminating 1% of the accidents.

It certainly is impossible.  Goodness knows I've never done it.  Not once.  In 480,000 miles on the road, every time a car out of control came at me from the side, I took my hands off the wheel, foot off the gas, and said "well, Lord, you've clearly put me in a position beyond my capability to correct" and allowed myself to get into the wreck without a fight.  Perhaps I screamed like some sort of an infant.

every single last damn time.  

Yep.  Quite sure that's how it happened.

[Hellfighter]

Wouldn't it be easier to put up a jersey barrier, but then, it looks ugly in rural areas.

[agentsteel53]

Wouldn't it be easier to put up a jersey barrier, but then, it looks ugly in rural areas.

the chains are a lot cheaper, which is why the state seems to want to go with them.

[rawmustard]

the chains are a lot cheaper, which is why the state seems to want to go with them.

It's cheaper to install, plus cheaper to repair than conventional guardrail. The whole point is to prevent much deadlier head-on collisions.

[Chris]

They wanted to install them in the Netherlands, but I think the plans were canceled after pressure from the national motorcyclist association. They're used extensively in Sweden to my knowledge. That's a place with bad winter weather too.

[Terry Shea]

It's impossible to avoid a car coming at you from the side or across your path.  But yeah, let's cause 99% more accidents by eliminating 1% of the accidents.

It certainly is impossible.  Goodness knows I've never done it.  Not once.  In 480,000 miles on the road, every time a car out of control came at me from the side, I took my hands off the wheel, foot off the gas, and said "well, Lord, you've clearly put me in a position beyond my capability to correct" and allowed myself to get into the wreck without a fight.  Perhaps I screamed like some sort of an infant.

every single last damn time. 

Yep.  Quite sure that's how it happened.

And how many head on collisions have you avoided?  You know you could try arguing from a factual/logical basis rather than your "I'm right because I say I'm right" sarcastic nonsense.  If a car is coming straight at me head on I can turn the wheel/swerve and avoid it.  If a car is coming straight at me from the side I can swerve and it's still going to hit me. 

And yes, a car careening off the barrier that gets turned in the other direction probably won't immediately have it's momentum shifted in the other direction, but it can still result in a head on collision and at 70 mph or more it really isn't going to matter much.  Dead, deader or deadest is inapplicable.  When you're dead you're dead.

[Terry Shea]

Wouldn't it be easier to put up a jersey barrier, but then, it looks ugly in rural areas.

These are ugly too.  I don't see a need for either.  If they're really concerned about reducing traffic deaths they should go back to a 55 mph speed limit (and no I'm not for that).  But once again I don't see how these are going to reduce traffic deaths and they are certainly going to increase accidents overall.

[Terry Shea]

a car that, in the absence of the cable, ends up in the median and stops is going to be a car that drifts harmlessly into the new cable.  The cars that get shredded are the cars that would go screaming into opposite-direction traffic.  Honestly, I'd rather have one car shredded than two.

Look again at the van in the video.  Does it look shredded?  No (other than the roof being somewhat caved in from landing on it)!  So I guess this must have been one of those vehicles that drifted "harmlessly into the new cable"...crossing 2 lanes of traffic, on its roof and facing in the wrong direction.  I'm betting the occupants of the van (and any traffic behind the van) would much rather have had the van simply enter the median and get stuck.

[InterstateNG]

Your claims are devoid of any proof.

[hbelkins]

Personally, I'm in favor of any kind of median barrier that prohibits police officers from whipping through the median to do a U-turn to ticket some poor soul who is driving at a safe speed but is in excess of an arbitrary posted limit determined by politicians instead of engineers. 

[agentsteel53]

Look again at the van in the video.  Does it look shredded?  No (other than the roof being somewhat caved in from landing on it)!  So I guess this must have been one of those vehicles that drifted "harmlessly into the new cable"...crossing 2 lanes of traffic, on its roof and facing in the wrong direction.  I'm betting the occupants of the van (and any traffic behind the van) would much rather have had the van simply enter the median and get stuck.

I don't think you can have it both ways.  Either it has enough momentum to travel the width of one median, or it does not.  The only thing the cable determines is whether that distance is covered straight across, or out and back again.

[agentsteel53]

And how many head on collisions have you avoided?  You know you could try arguing from a factual/logical basis rather than your "I'm right because I say I'm right" sarcastic nonsense.

and you could argue based on the laws of physics of this universe.  What's your point?

If a car is coming straight at me head on I can turn the wheel/swerve and avoid it.  If a car is coming straight at me from the side I can swerve and it's still going to hit me.

Yes, gravity attracts cars to each other.

And yes, a car careening off the barrier that gets turned in the other direction probably won't immediately have it's momentum shifted in the other direction,

About the first mathematically valid thing you've said all day.

but it can still result in a head on collision and at 70 mph or more it really isn't going to matter much.

do me a favor and do out the math for me on that one.  Your reality fascinates me; I'd like to see it in equation form.

Dead, deader or deadest is inapplicable.  When you're dead you're dead.

Leave statistics alone.  You're already making a mockery of physics.  You're allowed to show complete ignorance on precisely one scientific field per topic.

[froggie]

What do you think?  Personally I hate them.  They're ugly and I doubt they're going to save lives.

Experience elsewhere, not just in Texas but also in several other states (including Minnesota, which also has a winter), shows that they do save lives...

What happens when a motorcyclist hits a cable at high speed?

Here's what FHWA had to say:

Some motorcyclists have expressed concerns over cable barriers. Researchers in the United Kingdom, however, found little difference between crashes into cable median barriers and other barrier types. According to the data, most riders are separated from their motorcycles soon after leaving the pavement and are sliding on the ground by the time they reached the barrier. The data also did not show that cable barriers cause extraordinary injuries.

[realjd]

Here in Florida, we had crossover accidents (almost always fatal) on I-95 in my county almost weekly. And that's not an exaggeration. Northerners trying to make the 18+ hour drive in a single day would fall asleep, drift into the median, and hit oncoming traffic at full speed. The state has been actively working to put in median barriers. Some parts they used real guardrails, some places they put up the chains, some parts they put up Jersey barriers. Crossover accidents aren't an issue anymore here.

The cables don't bounce cars back into traffic, they're designed to grab the car so it stops in the median. I saw it happen once. A car went full-speed into the median, hit the cable, and the car stopped. If the chain hadn't been there, the car would have been coming directly at me.

Seeing the damage to the barriers from an accident isn't an uncommon sight, but I've yet to see a snapped cable. They're designed so that doesn't happen.

Motorcyclists are hosed no matter what they hit, cable or not.

[Scott5114]

Administrative Note (that's why it's in purple)–due to the contention that is occurring in this thread, you must cite your sources for all statistics and facts that you are attempting to post here, as demonstrated in this post. If you post without a source, moderation will be applied to your post. Thank you.

There is a MoDOT news release that shows in 2002, there were 24 crossover-related fatalities on I-70. In 2008, after cable barriers were installed, there was 1. Meanwhile, on I-44, prior to the cable barrier's installation, there were 25 crossover fatalities in 2006, whereas there were exactly zero in 2008 after the barriers were installed. [1]

MoDOT is using three-cable systems that cost $100,000 per mile to use.[2] They've installed about 550 miles of them at a cost of around $55 million. Oklahoma DOT is insisting on $125,000/mi systems that use four cables. Both meet the federal minimum standards, but ODOT says their four-cable systems are more effective against semis. There was a minor controversy when ODOT used stimulus money on the more expensive barriers.[2]

Rather than disputing the barrier's effectiveness, which has been proven beyond all doubt, the question is whether it is effective enough to justify its cost. I'd say it is–although it cost $1.1 million to save each life in Missouri, that investment will continue to perform for years. And I sure would have no problem with the state spending a million to save me.
____
1. http://www.modot.mo.gov/newsandinfo/District0News.shtml?action=displaySSI&newsId=29500
2. http://www.newson6.com/Global/story.asp?S=11576458

[Chris]

Here's what FHWA had to say:

Some motorcyclists have expressed concerns over cable barriers. Researchers in the United Kingdom, however, found little difference between crashes into cable median barriers and other barrier types. According to the data, most riders are separated from their motorcycles soon after leaving the pavement and are sliding on the ground by the time they reached the barrier. The data also did not show that cable barriers cause extraordinary injuries.

Barriers (cable or regular) on a straight alignment are not that dangerous to motorcyclists that they require extra safety features, such as aluminum plates in the open sections between the poles (to prevent decapitation). However, it is recommended in curves, especially cloverleafs. This specifically applies to metal guardrails, and not to concrete jersey barriers of course. If a motorcyclist slides on a wet pavement, you don't want him slashed in half by a pole of a guardrail. This issue is less of a problem in the United States as jersey barriers are far more common than guardrails which are prevalent in Europe.

Motorcyclist-friendly guardrail:

[Brandon]

I've noticed that IDOT has installed these along I-55 and I-80.  Now, I question the cost of them since the ones on I-55 from I-80 to Weber Rd (Exits 250 to 263) were replaced a year or two after installation due to the addition of a third lane in each direction with a jersey barrier in the median.  If the road needs widening, and will be widened soon to include a jersey barrier, should cable barriers be installed?

(Scott is right about effectiveness, my question is purely about replacement shortly after installation.)