Basics of Concrete Barriers (2000)

That timber-faced guard rail looks fantastic! And I wonder if its "weak" outward appearance will cause people to drive more cautiously

The concrete barrier industry moves at a fast pace (so to speak).

I wonder how much of this stuff from 2000 is still relevant?

Back then moor anchor law was still in full swing, for one thing.

The wire rope barriers have been installed all over Texas interstate highways which, in the past had no barriers to prevent traffic from crossing medians into oncoming traffic. A lot of bad accidents happened when vehicles crossed a grass median and slammed head-on into oncoming traffic. Years ago in an ice storm I almost became a statistic when a vehicle hit some black ice and the driver lost control, launching their vehicle across the median towards our vehicle.

They had installed miles of these wire rope barriers in the last 10 years and I have seen them being installed up in Oklahoma too.

Of course, once there is an accident the wire rope may have been strained past its rated capacity so it needs to be replaced. You can buy spools of the wire rope [0] from recycled materials handlers. Along the interstates near my place you will see skid marks into the cable barriers every time the highways get wet. If the weather was really bad you could find a dozen new collision spots in a 20 mile stretch. It keeps the repair crews busy. People drive too fast out here nowadays.

The pdf document posted is a great read. I see several barrier designs there that I have never seen in use anywhere and all the familiar ones too.

The most common barrier for many years in Texas has been the W-beam SGR04B type or similarly, the thrie-beam rail SGR09B but they tend to use treated timber posts for mounts. The newer installations have impact-absorbing lead-ins to help prevent fatalities.

A couple years ago I was driving home along a two-lane US highway (not an interstate) where the W-beams were used at every creek or river crossing. As I rounded a long curve in the highway headed downhill towards a creek crossing about 1000' away (305 m) I saw skid marks leading to the edge of the highway where the guard rails should've been. The skid marks were obviously made by an 18-wheeler (semi) truck-trailer. The guard rail was completely wiped out and as I passed the creek I saw where it came to rest. The entire length of rail was curled and twisted with one end up more than 30' (9.1 m) in a tree beside the creek more than 30' (9.1 m) off of the highway and the other end curled down near to the ground. It had been launched up into the tree by the force of the collision.

[0] https://www.repurposedmaterialsinc.com/median-galvanized-cab...

These have been lifesavers. Highway 101 in South San Jose used to be called "Blood Alley" for lack of effective separators. The biggest reduction in traffic fatalities historically accompanied their adoption.

However the US improvement is 3-5X less than other similar countries. For details on that and links to some data sources, see https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4103211/

I owe my life to these barriers.

In 1999 I was driving a '68 Plymouth Barracuda southbound on US395 in Reno, NV USA, doing 65-70mph in the fast lane (the lane closest to the middle barriers).

Being an older car, the 'Cuda had a tendency to drift to the left, toward the barriers. I corrected to the right, as I always did. Nothing happened. The joint connecting the steering column to the steering box, held together by a flimsy piece of sheet metal, had come apart.

I was now a passenger, and didn't dare not slam on the brakes, lest the all drum brakes send me in some unknown direction as they often did. If you're getting the idea this car needed some TLC, you'd be right.

With only a second or two to think about what to do, I simply let off the accelerator. The car started slowing slightly, but by the time the car drifted gently into the barrier, I was still travelling at at least 60mph.

My imagination saw me bouncing off the barrier, back into the fairly steady Reno afternoon traffic, where I'd be bounce like a pinball between other cars, eventually going sideways, flipping, and probably not surviving. I hoped nobody else got seriously hurt.

But that wasn't what happened.

The Cuda's front left tire caught the bottom of the barrier- the steepest angle the barrier has- and the front tires immediately slammed hard to the left. Now, both my front tires were at full lock left at 60mph. I expected to flip over.

Once again, that wasn't what happened.

Instead of flipping, the front left corner of the car became airborne for only a moment. Without traction, the front end just came back down, unable to continue its journey past about 40 degrees to the right. I'm guesstimating here, since at this point I was simply enduring the ride and out of my mind with fear. I didn't scream.

The cycle repeated itself, and each time the car lurched into the air, it lost speed. After several cycles, I realized that the car had stopped climbing the barrier and was the front tires were just skidding forward against the barrier and the pavement. It was only then that I thought it safe to press the brakes.

Finally, the car came to rest. After I stopped shaking internally, I realized the car's engine was still running. I turned it off. I was alive, and I realized in a very short time that I owed my life to the engineers who designed the Jersey barrier.

After reading this article, my appreciation soars even higher. All of the things that happened to me in my car weren't accidental: They were designed.

Thanks, Jersey barriers. I owe you one.

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As an aside to that story, I was about to horse-trade that car (straight across, no money changing hands) for a 1969 Land Cruiser FJ55 wagon just that week. I was sure that the trade would be a bust, but when I looked out the window, I saw that the only body damage was a bent fender lip! The barrier's design really shined even greater in that moment.

$100 to a not very friendly tow truck driver got me and the car home, and the very next week I was driving a 1969 FJ55 wagon. That vehicle was actually less safe, but way, way, more fun. And the new owner? He was doing a ground up resto anyway, and didn't care about the bent wheel, ruined tire, and broken ball joint. It was all being replaced anyway.