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Get used to 'diverging diamond' interchanges

We are new to the area. Why is the newly-opened Phoenix I-5 interchange designed the way it is? It seems overly complex with having to drive on the wrong side of the road, and having to yield to the right when getting off the highway makes it difficult to see the traffic with the right of way, especially if you are driving a truck or other vehicle with a limited view to the right.

— G.K., Medford

It's a bit strange, we'll grant you that, G.K. Hopefully, it will become second nature to you soon enough. Then you can let us know you have it nailed down and teach us.

We both need to get used to it, it sounds like. These types of interchanges are likely going to become more commonplace in the coming years, the folks at the Oregon Department of Transportation tell us.

"Today, there are 81 "diverging diamond" interchanges in use in the U.S. They are either in design, construction or use in 48 states," ODOT spokesman Gary Leaming says in an email.

There's an online map showing all the locations where such interchanges are in use, under construction, or are being designed across the country. You can view this map at http://www.divergingdiamond.com/ddi-map.html. A look at that map indicates these interchanges are quite popular in the Midwest, especially Missouri.

Leaming says the interchanges are less expensive to build, have a smaller footprint and move traffic more efficiently — and safely — than a "standard diamond." Safety benefits include shortened pedestrian crosswalk distances and better sight distance at turns. It's also pretty darn hard to make a wrong way jaunt up an offramp.

— Send questions to “Since You Asked,” Mail Tribune Newsroom, P.O. Box 1108, Medford, OR 97501; by fax to 541-776-4376; or by email to youasked@mailtribune.com. We’re sorry, but the volume of questions received prevents us from answering all of them.