This showed up in my facebook newsfeed. It is apparently a Chinese student's idea. What do you think?
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fimg.photobucket.com%2Falbums%2Fv226%2Fberberry%2Fimage_zps5f88bead.jpg&hash=fac3507589434ae0e1348f0431f90fc32a1b5353)
Little U-Turn ramps, how cute.
Looks interesting
It seems like if it was real, the slope would be too much.
I know, and it looks like it could be used to improve busy intersections on ordinary streets, simce it doesn't seem to require much space.
Those off-ramps (to turn) seem to have about a 25% grade.
Quote from: 1 on August 31, 2013, 02:36:49 PM
Those off-ramps (to turn) seem to have about a 25% grade.
Which is why I'm thinking it would be most useful where traffic doesn't move very fast anyway but could benefit from a removal of signals to allow slow but free flow. The only way I could see it being used on a freeway is if traffic exiting or entering the freeway, which should be the lower road, were to be separated from the main lanes, as with a protected cloverleaf.
http://www.china.org.cn/china/2011-04/08/content_22316107.htm (hey Beavis, that's not a cloverleaf heheheh)
QuoteXiao Rucheng, professor at Shanghai-based Tongji University, told China Daily the size of the bridge would be much larger than expected if put into construction. If so, it would lose the value of fitting into small junctions.
It's a typical modern third-world or 1940s first-world design. And that cityscape is 1950s urban renewal grand empty plazas.
I like the way all the trucks are using the left most lane of the freeway, something that is illegal is some countries.
Not bad, except that I hate left exits. But I guess it would still be effective.
I would imagine most actual implementations would get rid of the u-turn ramps.
Notice the white cars in the lower left. Their lane simply ends.
Quote from: jeffandnicole on August 31, 2013, 04:00:43 PM
Notice the white cars in the lower left. Their lane simply ends.
I think that lane merges with the light blue cars.
It seems like it would work with little traffic but the off-ramp from the major road to the elevated road could get backed up with cars waiting to merge.
If the grading is a problem, it looks like this would be a good idea with a major road intersecting two one-way streets.
On a different note, the weaving for the left turn motions would be awful for a high-traffic intersection.
Looks like it would make a fun go-cart track.
So, this (https://www.google.com/maps?ll=26.088123,-80.167333&spn=0.004013,0.006947&t=k&dg=opt&z=18) more or less.
The issues I see with this are manyfold:
#1: left exits or entrances
#2: tight turning radii
#3: as mentioned before, to get ramps that short would require VERY steep grades on the ramps
#4: would require lots of bridging or retaining walls, both of which would drive the cost up considerably
#5: requires a roadway that already has a wide right-of-way, especially for those U-turn ramps.
If we're talking about two non-freeway routes, would be more beneficial to just put in a CFI or flyover. Heck, even a "volleyball" would be more space-efficient.
A tight SPUI would probably be more effective, or even a three-level stacked roundabout. Or like froggie says you could put in a CFI.
Quote from: empirestate on September 01, 2013, 12:34:11 AM
So, this (https://www.google.com/maps?ll=26.088123,-80.167333&spn=0.004013,0.006947&t=k&dg=opt&z=18) more or less.
Very cool, thanks for sharing!
Note, as well, when you start incorporating those overpasses, you go from 5 lanes to no more than 4, and most likely 3. I think the creator purposely left those skip lines off the overpasses, realizing the limitations to the design. By looking at it, the cars are quite tight next to each other on the overpasses. Thus, traffic wouldn't be as free-flowing as it appears.
Quote from: johndoe on September 01, 2013, 10:02:20 AM
Quote from: empirestate on September 01, 2013, 12:34:11 AM
So, this (https://www.google.com/maps?ll=26.088123,-80.167333&spn=0.004013,0.006947&t=k&dg=opt&z=18) more or less.
Very cool, thanks for sharing!
By the way, is my example (I-95 at Florida SR 84) unique, or are there others like it? I don't know of any.
Not to mention the terrible amount of weaving that intersection would require for people wanting to enter a road and to exit.
No thanks.
EDIT... originally asked "How exactly is the artery going from left-right supposed to turn left? "
I see it now.
Quote from: empirestate on September 01, 2013, 03:47:38 PM
By the way, is my example (I-95 at Florida SR 84) unique, or are there others like it? I don't know of any.
There's a half version at DC 295 and Benning Road (and it has a random U-turn ramp): https://maps.google.com/maps?ll=38.895805,-76.952239&spn=0.003211,0.007086&gl=us&t=k&z=18
This would be slightly more feasible by using the outermost lanes to cross over the intersecting road, and having the innermost lane(s) for the right-turn movements. That would also allow the bike lanes and sidewalks to continue over. The bike lanes/sidewalks on the lower street would have to rise up to meet the ones on the upper street to avoid the ramps, and then cross over _somehow_ (I'm thinking these alternate between intersections where the next road is on the bottom, top, bottom, etc.)