Median Cable Guardrails-good or bad?

[agentsteel53]

how much of the cost could be recovered given that the cable was already manufactured and could, theoretically, be used in another location?

[mightyace]

how much of the cost could be recovered given that the cable was already manufactured and could, theoretically, be used in another location?

That provokes an interesting question.  Can the cables be reused if they are removed from one area?  Or is there some issue with the metal that would prevent that.

[hbelkins]

That provokes an interesting question.  Can the cables be reused if they are removed from one area?  Or is there some issue with the metal that would prevent that.

My guess would be that the cables would be fine, but the posts would have to be replaced. I see torn-up cable barriers along WV's I-64 east of Huntington all the time.

[Terry Shea]

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

I'm not saying that they don't prevent crossovers and deaths.  I'm saying that they will cause more accidents in total and involve more vehicles.  I think this is obvious because every time a vehicle comes into contact with the cable/post whatever there is going to be damage.  And certainly vehicles will be bounced back into traffic as the van in the video apparently was.  I'm not citing any statistics or sources because I don't believe any studies were done in this regard...the studies apparently only focused on the crossover aspect.

At any rate I'm just giving my opinion on this matter.  Apparently any opinion uttered that differs from the moderators here is treated in much the same way a communist country treats its peasants.

[Edited to fix coloring in quote, which I biffed in the original post. -S.]

[agentsteel53]

I'm not saying that they don't prevent crossovers and deaths.  I'm saying that they will cause more accidents in total and involve more vehicles.  I think this is obvious because every time a vehicle comes into contact with the cable/post whatever there is going to be damage.  And certainly vehicles will be bounced back into traffic as the van in the video apparently was.  I'm not citing any statistics or sources because I don't believe any studies were done in this regard...the studies apparently only focused on the crossover aspect.

the reason the studies focused on the crossover aspect is because that is the sort of accident that leads to the most fatalities, damage, etc.  You're basically giving up incident-free median entries in exchange for median departures that are significantly reduced in the level of harm they cause.  On a scale of 1 to 10:

0 - entering the median and coming to a stop
1 - entering the median and crashing into the new cable fence, coming to a stop in the median with some damage
5 - entering the median, bouncing off the fence, re-entering your direction of travel
10 - entering the median, passing straight through, and heading into opposite-direction travel

basically you're incurring a lot more "oh, dang, gotta call the insurance company" scrapes at the expense of horrifying head-on wrecks.  Seems like a decent bargain to me.  

At any rate I'm just giving my opinion on this matter.  Apparently any opinion uttered that differs from the moderators here is treated in much the same way a communist country treats its peasants.

I'll bet you've never actually been a resident of a communist country, peasant or otherwise.

[Scott5114]

Don't know if you're referring to me or not, but by requiring sources I'm attempting to encourage the members to do research and think about it before posting, thus raising the tone of discourse. If you want no moderation whatsoever, by all means, MTR is still available, but I think if you spend enough time around there you'd be happy to have moderation. The mod-free environment there directly results in Carl Rogers, Racist Roadsign Randy, and other terribly cool people like that.

Also, please note that our moderators often do not post in a moderation capacity. We like to join in on the discussion and express our opinions as much as you. Sometimes it can be misinterpreted. As a result whenever I speak as a moderator I try to color the words purple to help accentuate that fact.

That said, what is your source for the assertion that cable barriers cause bounceback? If that were a legitimate concern, I'm sure that a study would have addressed that. Or is that not what you meant by "they will cause more accidents in total and involve more vehicles"? Cable barriers are a legitimate safety feature, not like red-light cameras, which actually cause more accidents. I'm not seeing how cable barriers cause more accidents in total–can you source that claim?

[roadfro]

I'm not saying that they don't prevent crossovers and deaths.  I'm saying that they will cause more accidents in total and involve more vehicles.  I think this is obvious because every time a vehicle comes into contact with the cable/post whatever there is going to be damage.  And certainly vehicles will be bounced back into traffic as the van in the video apparently was.  I'm not citing any statistics or sources because I don't believe any studies were done in this regard...the studies apparently only focused on the crossover aspect.

The MDOT's cable barrier brochure (linked on the website given in the initial post) states "The cable also absorbs most of the impact, preventing the vehicle from bouncing back into traffic."  Granted, there may be times where the vehicle might bounce back, but the vehicle will be 'caught' in the cables more often than not.

Another thing to mention is that the flexibility of the cable barrier system diffuses the impact felt by passengers of the errant vehicle (http://www.nevadadot.com/safety/improvements/cablebarrier.asp).  I would imagine that would be far more jarring if a vehicle ran into a guardrail or concrete barrier wall.


NDOT has been swayed by the reported effectiveness of cable barriers.  They are installed in no fewer than three separate areas along US 395 (north of Reno, on the Carson City Bypass, and south of Carson City).

[Terry Shea]

Don't know if you're referring to me or not, but by requiring sources I'm attempting to encourage the members to do research and think about it before posting, thus raising the tone of discourse. If you want no moderation whatsoever, by all means, MTR is still available, but I think if you spend enough time around there you'd be happy to have moderation. The mod-free environment there directly results in Carl Rogers, Racist Roadsign Randy, and other terribly cool people like that.

Also, please note that our moderators often do not post in a moderation capacity. We like to join in on the discussion and express our opinions as much as you. Sometimes it can be misinterpreted. As a result whenever I speak as a moderator I try to color the words purple to help accentuate that fact.

That said, what is your source for the assertion that cable barriers cause bounceback? If that were a legitimate concern, I'm sure that a study would have addressed that. Or is that not what you meant by "they will cause more accidents in total and involve more vehicles"? Cable barriers are a legitimate safety feature, not like red-light cameras, which actually cause more accidents. I'm not seeing how cable barriers cause more accidents in total–can you source that claim?

How many times do I have to state the obvious?  A vast majority of vehicles that enter the median, stay in the median and incur no damage.  Now a vehicle that would have harmlessly entered the median unscathed is going to suffer extensive damage from the cables, the posts or both.  They may very well be flung back into lanes of traffic as the van in the video was.  Did you look at the MDOT video?  The van ended up on the opposite shoulder across 2 lanes of traffic, on its roof and facing the wrong direction.  And this is the video they're using to advertise the "safety" of such barriers.  That does not sound like a very safe scenario to me!  There is no evidence that the van would have crossed over to the other side w/o the barrier.  In fact most Michigan medians are quite recessed with soft, soggy, muddy ground, if not covered with 2 feet of snow, making crossovers or re-entries almost impossible. 

I've seen no study that addresses the bounce back factor or other concerns many people have.  That's why I started a thread asking for a discussion of this matter.  But apparently some moderators don't want a civil discussion of this matter to take place, and I know for a certain that one in particular has a personal vendetta against me.

[Scott5114]

What study do you have that shows that soggy, recessed medians are adequate to stop a car from crossing over? I can imagine it slowing down, but not stopping completely.

[Terry Shea]

Another thing to mention is that the flexibility of the cable barrier system diffuses the impact felt by passengers of the errant vehicle (http://www.nevadadot.com/safety/improvements/cablebarrier.asp).  I would imagine that would be far more jarring if a vehicle ran into a guardrail or concrete barrier wall.

You just touched on part of the problem which seems to be a rather large misconception here.  Yes the cable barrier would be much less jarring than a regular guardrail or concrete barrier...but they aren't replacing such structures!  They're being erected where no barrier existed before and where none should be necessary.  In fact I drove between Lansing and Grand Rapids along I-96 last night and saw several instances where guardrails were left in place and new cable barriers butted up to them. 

If they simply wanted to replace guardrails with them I probably wouldn't have a problem with them, but they're erecting them in lightly traveled rural areas, many times along a straight roadway for apparently no other reason than to clutter up the landscape and waste more Michigan taxpayers money.

[Terry Shea]

What study do you have that shows that soggy, recessed medians are adequate to stop a car from crossing over? I can imagine it slowing down, but not stopping completely.

Spend some time in Michigan.  Count how many times you find a car in the median that can't get out on it's own.  Actually that would be a futile quest now because most of the barriers have already been erected.  Once again, I'm sure no such study exists.  Once again, I'm sure you already know that, and once again you apparently don't want me to express my opinion. 

Let's just say I've been a Michigan resident for 51 years.  I know this state.  I know the highways.  I know the weather.  It's wet most of the time causing for soggy ground conditions, except in the winter time when it's often  covered in several layers of snow.  The medians don't get plowed out.  In fact the medians will accumulate an even greater amount of snow because the snow removal equipment will dump more snow into the median.  This brings up another point.  I wonder what the county commissions that are responsible for removing snow feel about these barriers.  That could be a real hindrance to them.

[realjd]

A vast majority of vehicles that enter the median, stay in the median and incur no damage.  

Do you have a source for thaT?

My county, Brevard County, FL, had 123 fatal crashes on our 70-some mile stretch of I-95 between 1994 and 2001, 1/3 of them being due to crossover accidents. That's about 6 fatal crashes per year that were crossover related in my county alone.

http://www.transportation.org/sites/aashtotig/docs/Florida%20DOT%20Presentation%20%28Keel%29%20%28June%202006%29.pdf
http://www.gannett.com/go/newswatch/2001/february/nw0216-1.htm

I couldn't find any more recent data, but it continued to be a significant problem until last year. 6 per year seems low to be for the past few years, but I don't have any actual data to back that up.

Maybe our medians are designed poorly here, or maybe it has to do with the fact that the grass is often slick with rain, but it's very rare to see a car stuck in a median here. They hit the median and then rocket into oncoming traffic. Why wouldn't they? What's so magical about medians that they cause cars to stop? Cars tend to rocket across the median into traffic. They've since put in a concrete barrier where they're widening I-95, traditional metal barriers south of that construction, and cable barriers in other places. The number of crossover accidents since has been zero. It has saved lives here (potentially including mine - I would have been hit once a few years ago if it weren't for a median barrier).

[agentsteel53]

I wonder what the county commissions that are responsible for removing snow feel about these barriers.  That could be a real hindrance to them.

one does not need to remove all the snow from the median.  Just over the paved section (maybe two feet wide past the innermost lane), and the new barrier should not interfere with that.

[agentsteel53]

It's wet most of the time causing for soggy ground conditions, except in the winter time when it's often  covered in several layers of snow. 

the van in the video is sufficient counterexample to your implication that the snow and sog and mud is enough to stop a car from crossing the median entirely into opposing traffic. 

The van had enough momentum to travel halfway into the median, bounce off the rail (which saps some momentum) and travel halfway out of the median again.  Had there been no median, that van would've crossed completely.

indeed, there is a wreck in the video, and it is bad, but it is - with good probability - less disastrous than what would've happened had the van gone into the opposite lanes. 

[Scott5114]

[This post is not made as a moderator and does not reflect the opinion of the staff.]

Spend some time in Michigan.  Count how many times you find a car in the median that can't get out on it's own.

You are the one making the assertion. The burden of proof is on you to back it up. Going to Michigan is financially untenable for me, and were I to do so it is unlikely I would be witness too many vehicles entering the median, unless Michigan drivers are completely incompetent. Which I am pretty sure they are not.

Once again, I'm sure no such study exists.  Once again, I'm sure you already know that, and once again you apparently don't want me to express my opinion.

Opinions should only be expressed when they are based on solid facts. Facts are made solid when they have evidence backing them up. If you can't express your opinion and back the facts it's based on up with sources, then you're damn right, I don't want you to express your opinion. If I wanted opinions based on gut feelings and superficial thought about the subject, I'd go talk to random people in the supermarket about it. But this is a road forum; we're supposed to be informed about what we're talking about.

The fact is, you're basing your opinion on certain things you assert to be true, yet when I question your assertions, you're not providing anything to make me believe they are true. When I point this out you get defensive and accuse the moderators of being communists (which is an ad hominem attack, a logical fallacy, I might add). How do you expect to have a reasoned debate based on the facts if you refuse to prove that the premise of your argument is true?

[Terry Shea]

It's wet most of the time causing for soggy ground conditions, except in the winter time when it's often  covered in several layers of snow. 

the van in the video is sufficient counterexample to your implication that the snow and sog and mud is enough to stop a car from crossing the median entirely into opposing traffic. 

The van had enough momentum to travel halfway into the median, bounce off the rail (which saps some momentum) and travel halfway out of the median again.  Had there been no median, that van would've crossed completely.

indeed, there is a wreck in the video, and it is bad, but it is - with good probability - less disastrous than what would've happened had the van gone into the opposite lanes. 

Another misconception.  These barriers are not constructed in the middle of the median.  They're often just a few feet off from the shoulder and are often constructed on both sides of the roadway.  The van probably never even got a vehicle width off from the shoulder.

[Scott5114]

Another misconception.  These barriers are not constructed in the middle of the median.  They're often just a few feet off from the shoulder and are often constructed on both sides of the roadway.  The van probably never even got a vehicle width off from the shoulder.

That seems like a deficiency in MDOT's implementation of the cable barrier, though, more than something endemic to the barriers themselves. OK generally constructs one cable barrier in the center of the median, more or less, though it may dodge to one side or another to avoid median obstructions like gantries, bridge piers, etc.

[Terry Shea]

A vast majority of vehicles that enter the median, stay in the median and incur no damage. 

Do you have a source for thaT?

My county, Brevard County, FL, had 123 fatal crashes on our 70-some mile stretch of I-95 between 1994 and 2001, 1/3 of them being due to crossover accidents. That's about 6 fatal crashes per year that were crossover related in my county alone.

http://www.transportation.org/sites/aashtotig/docs/Florida%20DOT%20Presentation%20%28Keel%29%20%28June%202006%29.pdf
http://www.gannett.com/go/newswatch/2001/february/nw0216-1.htm

I couldn't find any more recent data, but it continued to be a significant problem until last year. 6 per year seems low to be for the past few years, but I don't have any actual data to back that up.

Maybe our medians are designed poorly here, or maybe it has to do with the fact that the grass is often slick with rain, but it's very rare to see a car stuck in a median here. They hit the median and then rocket into oncoming traffic. Why wouldn't they? What's so magical about medians that they cause cars to stop? Cars tend to rocket across the median into traffic. They've since put in a concrete barrier where they're widening I-95, traditional metal barriers south of that construction, and cable barriers in other places. The number of crossover accidents since has been zero. It has saved lives here (potentially including mine - I would have been hit once a few years ago if it weren't for a median barrier).

Well that does sound awfully high.  According to the MDOT website they think they can save 13 lives per year in cross-over related accidents:
http://www.michigan.gov/mdot/0,1607,7-151-9620-227502--,00.html
So I would venture to say that our medians are better designed to keep cars in the median, especially since you get no snow or ice storms there that far fewer cars should venture into the median and yet you get a lot more cross-over accidents.

[US71]

According to the MDOT website they think they can save 13 lives per year in cross-over related accidents:
http://www.michigan.gov/mdot/0,1607,7-151-9620-227502--,00.html
So I would venture to say that our medians are better designed to keep cars in the median, especially since you get no snow or ice storms there that far fewer cars should venture into the median and yet you get a lot more cross-over accidents.

Whoa, hold the phone! No snow or ice storms in Michigan, is that what you're saying? . I'm not sure otherwise what you are saying.

[realjd]

So I would venture to say that our medians are better designed to keep cars in the median, especially since you get no snow or ice storms there that far fewer cars should venture into the median and yet you get a lot more cross-over accidents.

I'll buy that. Here's an example of a typical Florida median:
http://maps.google.com/?ie=UTF8&ll=28.205321,-80.713613&spn=0,359.972534&z=16&layer=c&cbll=28.205469,-80.711139&panoid=YO97wJscvpe9mrs1fbodAA&cbp=12,327.93,,0,3.38

Notice how flat it is? In some parts of the state, they left vegetation in the middle to act as a natural barrier. I don't know why they didn't do that more, or make the ditch/trench in the middle deeper.

Here's another example of an even narrower, worse median, this one with a cable barrier that gets frequent use:
http://maps.google.com/?ie=UTF8&ll=28.449789,-81.086397&spn=0,359.945068&z=15&layer=c&cbll=28.452107,-81.062827&panoid=7MFRlJNYc5fEHjiRFPOfFA&cbp=12,120.65,,0,5.28

[Terry Shea]

[This post is not made as a moderator and does not reflect the opinion of the staff.]

Spend some time in Michigan.  Count how many times you find a car in the median that can't get out on it's own.

You are the one making the assertion. The burden of proof is on you to back it up. Going to Michigan is financially untenable for me, and were I to do so it is unlikely I would be witness too many vehicles entering the median, unless Michigan drivers are completely incompetent. Which I am pretty sure they are not.

Once again, I'm sure no such study exists.  Once again, I'm sure you already know that, and once again you apparently don't want me to express my opinion.

Opinions should only be expressed when they are based on solid facts. Facts are made solid when they have evidence backing them up. If you can't express your opinion and back the facts it's based on up with sources, then you're damn right, I don't want you to express your opinion. If I wanted opinions based on gut feelings and superficial thought about the subject, I'd go talk to random people in the supermarket about it. But this is a road forum; we're supposed to be informed about what we're talking about.

The fact is, you're basing your opinion on certain things you assert to be true, yet when I question your assertions, you're not providing anything to make me believe they are true. When I point this out you get defensive and accuse the moderators of being communists (which is an ad hominem attack, a logical fallacy, I might add). How do you expect to have a reasoned debate based on the facts if you refuse to prove that the premise of your argument is true?

Now that's just ludicrous!  I can't post documentation that doesn't exist, either because it was simply overlooked by those making the studies or because they are deliberately trying to hide other factors (sound familiar?).  But it's obvious that more cars are going to be damaged by these barriers.  It's also obvious that these barriers can fling cars back across lanes of traffic (again, see the video).  There is absolutely no reason I shouldn't be able to express my opinion about them and there is no reason we shouldn't be able to carry on a civil discussion about the pros and cons.  If documented facts exist, great!  If there is no actual documentation, we can use other factors such as common sense.

Apparently you have no idea what winter driving is like in a state such as Michigan.  After getting even say 3 or 4 inches of snow over night (not an uncommon occurrence at all) you will no doubt see several cars in the median the next morning.  They do not cross over, they do not suffer any damage most of the time.  It's not that they're necessarily bad drivers.  It's just one of the hazards of living here and having to drive here under unfavorable winter conditions.  When it gets below about 25 degrees or so salt and chemicals either don't work or at least become much less effective.  You slow down and do the best you can, but inevitably somewhere, sometime you are going to slide and leave the roadway.  No big deal.  You call a wrecker and get pulled out. 

Now we're faced with running into these cable barriers, which will certainly cause damage and may very well throw us back into traffic under far less than ideal driving conditions.  I'd much rather just get pulled out of the median.

[Terry Shea]

According to the MDOT website they think they can save 13 lives per year in cross-over related accidents:
http://www.michigan.gov/mdot/0,1607,7-151-9620-227502--,00.html
So I would venture to say that our medians are better designed to keep cars in the median, especially since you get no snow or ice storms there that far fewer cars should venture into the median and yet you get a lot more cross-over accidents.

Whoa, hold the phone! No snow or ice storms in Michigan, is that what you're saying? . I'm sure otherwise what you are saying.

No, I was responding to a post from Florida and comparing the 2 scenarios.

[Terry Shea]

So I would venture to say that our medians are better designed to keep cars in the median, especially since you get no snow or ice storms there that far fewer cars should venture into the median and yet you get a lot more cross-over accidents.

I'll buy that. Here's an example of a typical Florida median:
http://maps.google.com/?ie=UTF8&ll=28.205321,-80.713613&spn=0,359.972534&z=16&layer=c&cbll=28.205469,-80.711139&panoid=YO97wJscvpe9mrs1fbodAA&cbp=12,327.93,,0,3.38

Notice how flat it is? In some parts of the state, they left vegetation in the middle to act as a natural barrier. I don't know why they didn't do that more, or make the ditch/trench in the middle deeper.

Here's another example of an even narrower, worse median, this one with a cable barrier that gets frequent use:
http://maps.google.com/?ie=UTF8&ll=28.449789,-81.086397&spn=0,359.945068&z=15&layer=c&cbll=28.452107,-81.062827&panoid=7MFRlJNYc5fEHjiRFPOfFA&cbp=12,120.65,,0,5.28

Can't really judge the depth but they certainly do look narrow.  The only places we have medians like that are going through large metropolitan areas...and there aren't any of these cable barriers in metro areas.  There all in lightly traveled rural areas.

[InterstateNG]

Your vehement objection to these on Michigan roadways is...because they're ugly?  Because of all your claims, the only thing that can be proved substantively is that "Terry Shea thinks they are ugly".

[rawmustard]

When it gets below about 25 degrees or so salt and chemicals either don't work or at least become much less effective.  You slow down and do the best you can, but inevitably somewhere, sometime you are going to slide and leave the roadway.  No big deal.  You call a wrecker and get pulled out. 

Now we're faced with running into these cable barriers, which will certainly cause damage and may very well throw us back into traffic under far less than ideal driving conditions.  I'd much rather just get pulled out of the median.

I don't think you'll ever have an ideal solution that suits both high-speed and low-speed situations. But for the former, it sure is nice to have something that would impede momentum, yet not be so expensive to install. You're probably aware of the rollover crash which happened last night. You'd be hard pressed to argue that a barrier wouldn't lessen momentum, much less prevent the vehicle in question from going airborne (the chances being greater rolling or careening up a slope). Unfortunately, we won't know in this instance what could've been since a barrier wasn't present at the site of this accident, but just the idea that lives could be saved should outweigh any costs and inconveniences related to lower-speed slideoff damage. For that, I'm willing to have cable guardrails installed.