Cable barriers

[Farmwithjunk]

It's a stretch I'll admit, but this needs to be in the saftey forum I'd think.

Since many of us haul tractors on the interstates, highway saftey is an important consideration. I had a "demonstration" on this past Friday afternoon of a relatively new saftey feature on the highways in my area. Maybe you're already familiar with them. I'm talking about 3-strand cable barriers in the medians to prevent "cross-over" collisions.

I was on my way to the Massey Ferguson dealer pick up a few parts. It was early in the normal rush hour traffic flow. (around 3PM) Off in the distance, in the on-coming lanes, I could see cars and trucks starting to make what I'd call EVASIVE MANUEVERS. They were dodging a car that was driving too fast and too wreckless. It was a small "fast and furious" car replete with the popular rear wing, low profile 20" wheels, ect. Speed limit on this highway is 65. He was probably doing 100 in heavy traffic. I saw him pass a semi ON THE INSIDE saftey strip, NOT in a driving lane. Then he lost it. 2 wheels in the grass, then it drifted side-ways a bit. The driver over-corrected, went into the rear wheels of the truck, bounced off, and into the median. He got full sideways. Sliding along in the grass sideways, he was still going so fast that he was obviously passing other motorist's who were still travelling at the speed limit. He got lucky (so far) and the car turned back straight. It came back up on the pavement. He started to go towards another semi that was slightly behind the first one he hit. The driver turned back towards the grass. When he hit the grass this time, probably travelling at approx. 60 or 70 mph by now, the car swapped ends. He was backing up at almost the speed limit. The car went across the median, bound for the traffic lanes going in the opposite direction, MY direction. He WOULD have ran out into oncoming traffic, which was bumper to bumper, travelling at (or above) the posted 65 mph. It would have been a horrific wreck. Judging by the angle and timing, it would have involved me. Then, just along side of the lane I was in, he hit the 3-strand cables....backwards at 60 or 70 mph.

Ever see an aircraft carrier landing of a fighter jet?

The cables snagged the car, directing it along the cables for maybe 25 or 30 feet, slowing it's momentum in a heartbeat, preventing it from entering oncoming traffic, and PROBABLY saving numerous lives.

The top cable ended up on top of the car, holding it down. The middle cable slid along the side of the car, preventing it from continuing into oncoming traffic. The lower cable ended up under the car, guiding it straight and slowing it.

By the time everything was over, traffic was stopping in both directions. I pulled off the road into the median (on my side) I was in a state of shock for a few seconds. The driver of the car was out of his car in seconds. He was unhurt, but having what could best be described as a panic attack. He was "flipping out". His car was torn up, but still intact for the most part. No one was injured.

I was suitably impressed. (albiet a nervous wreck for a few minutes)

Every now and then, highway saftey engineers come up with a workable solution to prevent catastrophic auto accidents. They did in this case.

As much as anything, I'd like to make a public aknowledgment in favor of use of these cable restraint barriers. They do work. I'm here today BECAUSE they work. My thanks to Kentucky Dept. of Transportation. You all saved my butt on this day.

And for the record, the driver ended up being in his early 20's, DRUNK, and as the police noted when taking information from witness's, having no valid license. Also worthy of note, these cables were installed just this past winter and early spring. Timing IS everything.

 

[Bird]

Farmwithjunk, we've got hundreds of miles of that kind of median barrier in this part of the country. I'm not sure how long they've been doing it, but quite awhile. Some areas have the concrete barriers while others have the cable. I think what it amounts to, is that the shorter stretches have the concrete while the long stretches have the cables. Either one works well to prevent the cross over accidents. I recently read an article about them that said the cables are gaining favor because they cost less than the concrete to install. However, the cables require more cost for repairs and maintenance. In all probability, there will be some pretty expensive repairs to the cables where you saw that accident while there would have been none if it had been a concrete barrier. The only problem with the article I read was that it didn't tell what ratio the cost difference is, and in fact didn't give any dollar amounts for either the cables or the concrete.

I'd like to make a public aknowledgment in favor of use of these cable restraint barriers

I'd prefer the concrete barrier, but if the cost difference is sufficient, then I might be in favor of the cables. In any case, I like to have one or the other.

 

[jeffinsgf]

I read an article about the cables on the MODOT web site. It has some very convincing video on the page. The advantage of cables over a concrete median barrier is that they stop the accident cold, where a concrete median just prevents the accident from crossing lanes. A concrete barrier is just going to throw the fool back into the traffic flow.

In MO they are stretching miles and miles of cable barrier now. I realize it is a maintenance item -- but it looks like money well spent.

 

[GaryM]

They've somewhat recently completed barriers on I-70 in Missouri. Mostly cable in the rural areas and concrete in other areas. I drive about 45 miles of I-70 each way to work and back and see damaged cable sections most evry day. It seems like it takes them over a week to replace and repair damaged sections. But they do work!

 

[Bird]

A concrete barrier is just going to throw the fool back into the traffic flow.

Jeff, when the concrete barriers first started gaining popularity, there were some impressive videos used to sell that idea. The main point of the videos was that a vehicle hitting the concrete almost always continued to slide along, staying against the concrete rather than bouncing back out into traffic as had usually happened with the old metal barriers. I think everyone realizes that they can bounce back out into traffic, but not as easily as they did with metal.

 

[jeffinsgf]

You're right, Bird. I said "bounce back" when the design of the concrete barrier encourages the vehicle to slide rather than bounce.
What I meant was that the concrete barrier does little to stop the vehicle where the cables are working to stop as well as direct.

 

[scott_vt]

Mornin Bill,
Well this guy was definitely making a statement going 100 mph passing a tractor trailer on the inside safety strip !

We have a lot of the safety cable up this way but its usually used on the outside shoulder of our roadways, not in the center. But hopefully the state DOT chief is reading your post also !

 

[whodat90]

Unfortunately, while the cables do stop cars beautifully, the have a bad habit of killing and severing motorcyclists unfortunate enough to be involved with them. There are a number of systems available, and the cable systems are typically used because they're the cheapest.

 

[schmism]

Unfortunately, while the cables do stop cars beautifully, the have a bad habit of killing and severing motorcyclists unfortunate enough to be involved with them. There are a number of systems available, and the cable systems are typically used because they're the cheapest.

perhaps,

but your kidding yourself if you think the survival rate is anything more than "a handfull" for ANY "high speed" motorcyle accident reguardless of what they do or dont hit.

the statement "oh johny would have been fine after he was flung from his motorcycle going 60mph if he just wouldnt have hit that cable barrer" lacks a serious amount of realism.

 

[jeffinsgf]

... There are a number of systems available, and the cable systems are typically used because they're the cheapest.

I am not sure that is the case at all. Cable is labor intensive to install and requires significant maintenance after every accident. While I can see that motorcyclists would view it as a waiting garot, I think it is becoming more and more popular because it is very effective, not because it is cheapest.