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Dreaded double diverging diamonds are coming

Dreaded double diverging diamonds are coming

Click to enlarge (Google Maps)

What the freeway! Which way do you go? And what do you do when a traffic flow idea is so crazy it makes sense?

So I’m pulling off I-44 at exit 8 in Joplin, MO, my first time there. But since my GPS routing system showed my destination to be just a few blocks away on the other of the Interstate underpass, I turned it off as I approached the stop light at the intersection. And suddenly I was confused.

There were four lanes of traffic, but everyone seemed to going the wrong way.

I had encountered my first double diverging diamond interchange.

For truckers who put in 100,000 miles a year, maybe this traffic management scheme is old news. However, it was new to me and unwelcome after a long day on the road, just when I was mentally done for the day.

Nothing bad happened: Traffic was light, and I had the luxury of getting my bearings and going with the flow. The trick was not to think, and just roll—even as I could see the two lanes of traffic on the other of the underpass coming straight at me.

The interchange was no less confusing the next morning on my way out, when I was prepared and had taken a look at the traffic pattern on my routing device in advance. Again, the trick was not to think, just stay in the lane and don’t worry that you’re crossing onto the wrong side of the road for a bit.

Over a couple of days I used this intersection several times, and I still couldn’t get comfortable with it. And, on those several trips, I saw that I wasn’t the only one as a couple of 18-wheelers got caught in the wrong lane as they tried to get on I-44.

But, as someone who gave up on a civil engineering degree following a course on highway design and materials (I only thought I hated math before that), and as a newspaper City Hall reporter who covered a planning commission’s push for the first highway roundabout in the state, I realized this Joplin interchange must’ve been a standard design—it was just completely new to me. So I looked into it.

Turns out, the DDI has been around since 2009, and the first was actually built not far from Joplin in Springfield. There’s even a website devoted to it, and a Wikipedia page, of course. And, as every highway department looking into a double diverging diamond interchange will (and does) tell you, it was named one of the best innovations of 2009 by Popular Science.

Here’s the kicker: Turns out there’s one planned for the Interstate interchange closest to my house. It can’t hurt. I hope. But, based on my roundabout experience, people are not going to be at all happy with the idea, until it works. I’ll keep you posted.

In the meantime, if you come across some confusing bit of traffic management—or, even better, an innovation you like—please share it with other truckers. Drop me a line anytime. Photos are good, too.

TAGS: News Safety
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