Alabama's first diverging diamond interchange opening July 1

[MULTIZ321]

Alabama's first diverging diamond interchange opening July 1

Alabama’s first diverging diamond interchange opening July 1

The diverging diamond interchange at Alabama State Route 181 and Interstate 10 in Daphne and Spanish Fort will be open on July 1. The $7.3 million interchange project is a first of its kind in Alabama.

www.al.com

Richard

 

[pedro47]

Alabama's first diverging diamond interchange opening July 1

Alabama’s first diverging diamond interchange opening July 1

The diverging diamond interchange at Alabama State Route 181 and Interstate 10 in Daphne and Spanish Fort will be open on July 1. The $7.3 million interchange project is a first of its kind in Alabama.

www.al.com

Richard

I guess this is good news for the citizens of the State of Alabama.

 

[CanuckTravlr]

Interesting concept; I have never seen one before this. However, you still end up with two sets of traffic signals, one on each end of the crossover bridge, so it seems to be designed for a very specific set of circumstances.

I am thinking the only advantage to this design is in a less-urban location where a high-volume attraction drives a lot of traffic to the location via the freeway. So the back-ups tend to be traffic trying to get onto or off the freeway and therefore the priority is for that traffic, rather than the through traffic on the local crossover road. I am wondering if two roundabouts wouldn't work equally as well, if not even better? It would be interesting to observe how it actually works in practice.

 

[bbodb1]

@CanuckTravlr - your point on roundabouts was exactly the same thought I had. No traffic lights with roundabouts and no crossover of traffic.

Not sure why a double diamond was chosen here either.

 

[PamMo]

MoDOT built the first diverging diamond interchange in the USA in Springfield, Missouri back in 2009. It was very weird to drive through it the first few times, but it works great at streamlining traffic - much faster than a clover leaf interchange. We have several diverging diamonds now.

 

[PigsDad]

Interesting. They are currently rebuilding the interstate that goes through our area and at a few intersections they have been putting in roundabouts on each side of the interchange, so as you come off or go onto the interstate, you go through a roundabout. They work ok but after seeing the video above, it make me wonder if that would be more efficient. The big advantage of the roundabout interchange is that there are no traffic lights. I'm a big fan of the roundabout, as it eliminates the deadly T-bone accident at intersections.

This is what they look like:

Kurt

 

[bbodb1]

One can clearly see the benefit of the double diamond interchange in that it eliminates left had turns across oncoming traffic. That is a safety enhancement for sure.
But those traffic lights are still areas for possible (near) head on crashes - something that roundabouts eliminate.
And I have to believe roundabouts are cheaper to build than double diamonds.
Left hand turning traffic might be able to move through a double diamond faster than rounadabouts so there is an advantage there for double diamonds.

As is mentioned above, I suspect a thorough understanding of the traffic patterns in the immediate area was likely a determining factor toward double diamonds and not a roundabout.
It would be interesting to see if the firm / engineer discussed those considerations somewhere.

Bottom line: any improvement in traffic flow should save lives, fuel and time. Those are all positives.

 

[Talent312]

Interesting design. But IMHO, the title for the most mind-blowing interchange belongs to the venerable, Golden Glades Interchange in Miami-Dade, Florida. There, the following all come together: The Florida Turnpike, the Palmetto Expressway (SR 826), I-95, US 441, and N.167th Street.

...............

 

[krj9999]

We have one here in Maryland (exiting Baltimore-Washington Parkway near a large mall and casino). Too much traffic flow for roundabouts and cloverleafs.