Pennsylvania's first "diverging diamond" interchange coming to Washington County (Pittsburgh: hair salon, home)

[LIRefugee]

Originally Posted by UKyank

Ah, that makes things make alot more sense & proof that I apparently can't read. I thought it was a rendering for the Washington proposal.

If my memory is correct, there is only one type of this intersection in the entire country right now, so there wouldn't be much available except generated graphical depictions!

Again relying on memory, I think there's a couple-mile stretch of highway in Montreal where the travel lanes are flipped. Hopefully there won't be much confusion with the diverging diamond, so long as the lane stripes are painted on.

[Craziaskowboi]

Dammit, half of you only read half of what I typed!

I probably should have described the picture a little bit. The secondary road is the one that passes diagonally from the bottom-left corner of the picture to the top-right corner. It passes over the Interstate, which passes from left to right in the picture.




The Murtland Avenue interchange would be slightly different, in that the Interstate (I-70/I-79) would pass over the secondary road (Murtland Avenue) instead of under it. The design would otherwise be the same. There will be no traffic signals on the Interstate.

It's also worth mentioning that the function of the interchange sounds confusing until you try it, and then it becomes a lot more obvious how it works. People in Missouri had their minds blown too, until they drove through one for the first time.

Originally Posted by LIRefugee

If my memory is correct, there is only one type of this intersection in the entire country right now, so there wouldn't be much available except generated graphical depictions!

No, Missouri has constructed about a dozen of them so far, and Pennsylvania now joins 19 other states that have either built them or are ready to build them.

[LIRefugee]

Originally Posted by Gnutella

No, Missouri has constructed about a dozen of them so far, and Pennsylvania now joins 19 other states that have either built them or are ready to build them.

Aha! I misremembered then. According to the Wikipedia article, there are 11 or so interchanges of this type in the US, most in Missouri, and all built in 2009 or later. And there are a bunch on the drawing board in many places. It's becoming quite the trend, it seems.

[Hopes]

Originally Posted by Gnutella

Dammit, half of you only read half of what I typed!

I'm sorry! I'll do better next time! I promise! Please forgive me!

[escilade18]

Originally Posted by Copanut

Ah, who cares about that area, nothing but trailer parks in Wash County.

I see just what you are talking about lol Peters Township, PA - Google Maps

[escilade18]

Would this be a good representation of a diverging diamond interchange? Washington D.C., DC - Google Maps

[Lobick]

Originally Posted by escilade18

Would this be a good representation of a diverging diamond interchange? Washington D.C., DC - Google Maps

I don't believe so.

[ML North]

I think a larger picture will help alleviate some confusion.

Noteworthy, too, is that the DDI only requires 2 light cycles or phases.

[Ohiogirl81]

If you look at the picture long enough, this type of interchange really does make sense and I could see it working at I-70/U.S. 19. Naturally it would require a learning curve -- and really good signs (which Pennsylvania hasn't been so good at but is improving).

Another positive it that this interchange doesn't take up much more real estate than a traditional diamond interchange -- unlike cloverleafs, which also have the additional problem of being a general PITA.

[mjost7]

Yes, a signal phase is eliminated (that would otherwise be there in a traditional diamond interchange traffic signal). That means one less yellow/all red clearance interval with each cycle. If you have 60 cycles per hour and 5 seconds yellow/all red you save at least 300 seconds an hour.

Therefore productivity will skyrocket when drivers have an extra 300 seconds.

Interesting design. I like it.