AARoads Forum

National Boards => General Highway Talk => Topic started by: johndoe on July 27, 2014, 07:37:57 PM

Title: Variation on double crossover diamond (aka DDI) to be constructed
Post by: johndoe on July 27, 2014, 07:37:57 PM
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.athensnews.com%2Fohio%2Fimgs%2Fmedia.images%2F4505%2FEStateRevised2.widea.jpg&hash=a1043261770db365b39bcc4aff1e3c52079104dd)
http://www.athensnews.com/ohio/article-42432-plan-would-make-e-state-go-crossways.html
http://www.athensnews.com/ohio/article-42829-e-state_us-33-interchange-plan-selected.html

Just stumbled across this and thought some of you might enjoy it.  It should make for some interesting islands and signs!  I hope there is enough guidance for drivers (i.e. the northbound to westbound off-ramp movement not turning to eastbound lanes). 
Title: Re: Variation on double crossover diamond (aka DDI) to be constructed
Post by: jakeroot on July 27, 2014, 08:07:50 PM
Rather than make a left turn onto US 33 (N), why not just do a slip ramp to the right? That way, the left turn from US 33 (N) to E State Street (W) isn't handicapped. You could keep the free-flow with the loop ramp.

Wait, how do you get from E State Street (W) to US 33 (S)? Does the arrow just not exist on the diagram?

Also, the triple-carriageway setup reminds me of the DDI in Seclin, France (http://goo.gl/Njauum).
Title: Re: Variation on double crossover diamond (aka DDI) to be constructed
Post by: cl94 on July 27, 2014, 09:21:45 PM
Quote from: jake on July 27, 2014, 08:07:50 PM
Rather than make a left turn onto US 33 (N), why not just do a slip ramp to the right? That way, the left turn from US 33 (N) to E State Street (W) isn't handicapped. You could keep the free-flow with the loop ramp.

They'd have to buy a decent amount of property to keep within the standards. On such a busy road, they'd likely signalize the ramp termini. If this was the case, both signals would still have two phases. There will certainly be some interesting channelization, but keeping the loop ramp as is shown would not change the operation of the DDI.
Title: Re: Variation on double crossover diamond (aka DDI) to be constructed
Post by: vtk on July 27, 2014, 10:03:41 PM
Alternative 1: Diverging Parclo *3 or Half-Folded DDI

Very interesting indeed.

PS – US 33 is east-west in Ohio. At this location, geo north is sign west, and geo south is sign east.  Just "east" of here is a wrong way overlap with US 50 and SR 32 which is also Corridor D (or B or C maybe; I can't keep those letters straight).

*I can never remember which is which, of the A and B in parclo designations...
Title: Re: Variation on double crossover diamond (aka DDI) to be constructed
Post by: 2Co5_14 on July 28, 2014, 12:32:31 PM
Quote from: vtk on July 27, 2014, 10:03:41 PM
*I can never remember which is which, of the A and B in parclo designationsÂ…

Parclo A: loop ramp in Advance of interchange
Parclo B: loop ramp Beyond interchange