DDI Diverging Diamond Interchange

[botsapper]

Have any of you guys used/driven through this kind of traffic control configuration? Safer and faster; for all vehicles, bikes and pedestrians.

https://www.youtube.com/watch?v=UasNoY58cEY

[RedDevil]

Make the crossings split level, then you would not need traffic lights at all. Just a couple of bridges or tunnels to aid cyclists and pedestrians crossing the access roads.

Then, maybe the bridge itself could be split level. Double decked, it would be twice as narrow and maybe even cheaper to build. And again no traffic lights would be needed.

[star_deceiver]

More tunnels and overpasses add a lot of cost and need to be built big enough for oversized and superheavy transport trucks.

Removing pedestrians and cyclists completely helps a lot.

I've never driven one of these in a rush hour situation. They handle normal traffic well, though.

[freebeard]

Removing pedestrians and cyclists completely helps a lot.

Helps what, exactly, a lot? Certainly not the pedestrians and cyclists.

It looks reasonable. I've never driven one.

[Fat Charlie]

Safer and faster than squeezing your hand in a vise, perhaps. But preferable?

I absolutely hate airlock type traffic lights- where they're placed in pairs and the first light can do anything it wants, but you can't do anything until the farther light allows the gap between them to empty. Given traffic lag, you could sit through an entire green and be looking at another red before there's even room on the other side of your intersection to allow you to cross.

What's worse than airlock lights? Combined ramps, where accelerating traffic moving to the left gets to mix with decelerating traffic moving to the right. As an added bonus, this interchange also mixes in crossing traffic that doesn't want to get on the main highway at all.

A regular Diamond interchange has two lights on the secondary road, and traffic in both directions on the secondary road can be completely unimpeded by reds. The Diverging Diamond can't ever allow traffic in both directions at the same time on the secondary road.

We've already got one bridge here. A cloverleaf has a bridge and zero stoplights. None.

[The Other Andy]

I haven't, but I'd like to. It seems to be a very interesting interchange. If you're interested in stuff like that, you may want to check out skyscrapercity.com. They frequently get into discussions about roadway intersections.

[Natalya]

Ontario uses ****loads of Parclo A4 interchanges. All turns are right turns.
https://en.wikipedia.org/wiki/Partia...af_interchange

I have driven across a DDI interchange many times, I was confused as to why they didn't just make it an A4. (I used to drive on it before they turned it into a DDI.)

[jamesqf]

You know, this all makes me feel SO much better about having to occasionally stop to let a herd of wild horses cross the road :-)

[acparker]

These are used extensively here in Utah. Most new interchanges are done this way and many older ones are being rebuilt to the new configuration. They can get quite complex when dealing with frontage roads, but they still work better than the original.

Cloverleafs use a lot of space.

They also like the Displaced Left-Turn Intersection here for busy surface streets.

[star_deceiver]

Originally Posted by freebeard

Helps what, exactly, a lot? Certainly not the pedestrians and cyclists.

Can't speak for every community, but around here cyclists have little regard for and road rules. I have no problem with them having their own paths to cause chaos and keep them out of traffic.

DDI intersections are large and traffic doesn't follow normal patterns meaning slow and jay walking pedestrians get caught in traffic.

Giving them their own overpass or route saves everyone a headache.