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National Boards => General Highway Talk => Topic started by: TheStranger on October 15, 2013, 02:16:17 PM

Title: Left-exit cloverleaf ramps
Post by: TheStranger on October 15, 2013, 02:16:17 PM
Since cloverleaf ramps are usually used to allow traffic to exit right and merge from the right in what otherwise would be a left-turning movement, I thought this example at the East Los Angeles Interchange (I-5/Golden State Freeway north Exit 134C to East 7th Street) was rather notable:

https://maps.google.com/maps?q=E+7th+St+%26+S+Boyle+Ave,+East+Los+Angeles,+CA&hl=en&ll=34.033395,-118.219441&spn=0.005118,0.004774&sll=34.033014,-118.218926&sspn=0.005118,0.004774&t=h&hnear=E+7th+St+%26+S+Boyle+Ave,+Los+Angeles,+California+90023&z=18

It appears to be an adaptation of what was the original 1940s offramp from US 101/Santa Ana Freeway to 7th:

http://www.historicaerials.com/aerials.php?scale=8E-06&lat=34.0332010863852&lon=-118.22008611257&year=1948

though it seems that creating a full RIRO (instead of just an onramp) at East 7th and South Breed Street would have been an easier, more conventional option when the full East Los Angeles Interchange came to fruition.

Any other examples of this?
Title: Re: Left-exit cloverleaf ramps
Post by: agentsteel53 on October 15, 2013, 02:19:44 PM
I would like to see a left-exit, left-entrance, counterclockwise-rotating clover... in a right-side-drive country. 

in fact, any counterclockwise-rotating clover would be interesting. 
Title: Re: Left-exit cloverleaf ramps
Post by: 1995hoo on October 15, 2013, 02:25:39 PM
Quote from: agentsteel53 on October 15, 2013, 02:19:44 PM
I would like to see a left-exit, left-entrance, counterclockwise-rotating clover... in a right-side-drive country. 

in fact, any counterclockwise-rotating clover would be interesting. 

Can it be a single anticlockwise loop-around ramp without being part of a full cloverleaf? If so, there's one in Delaware: http://goo.gl/maps/PqRIz

Also, one of the new ramps connecting the Capital Beltway and the reversible HOV facility on Shirley Highway in Springfield, Virginia, operates as a left-exit, left-entrance anticlockwise loop-around for at least certain maneuvers at certain times of day. It's a reversible ramp, of course, so it's not always like that.
Title: Re: Left-exit cloverleaf ramps
Post by: TheStranger on October 15, 2013, 02:30:15 PM
Quote from: 1995hoo on October 15, 2013, 02:25:39 PM
Quote from: agentsteel53 on October 15, 2013, 02:19:44 PM
I would like to see a left-exit, left-entrance, counterclockwise-rotating clover... in a right-side-drive country. 

in fact, any counterclockwise-rotating clover would be interesting. 

Can it be a single anticlockwise loop-around ramp without being part of a full cloverleaf? If so, there's one in Delaware: http://goo.gl/maps/PqRIz


That would be the prototypical example!  Left movement as a substitute for a basic right-turn ramp...which is odd as there seems to be enough right of way for one.
Title: Re: Left-exit cloverleaf ramps
Post by: froggie on October 15, 2013, 02:55:38 PM
A lot of the acreage surrounding that Delaware example is wetland.

IIRC, Boston has something similar on the ramp from EB 90 to SB 93 as well as from NB 93 to the Tobin Bridge.
Title: Re: Left-exit cloverleaf ramps
Post by: agentsteel53 on October 15, 2013, 03:02:57 PM
Quote from: TheStranger on October 15, 2013, 02:30:15 PM
That would be the prototypical example!  Left movement as a substitute for a basic right-turn ramp...which is odd as there seems to be enough right of way for one.

I get the idea the water has something to do with it.
Title: Re: Left-exit cloverleaf ramps
Post by: jeffandnicole on October 15, 2013, 03:21:30 PM
Back in the day, that water probably wasn't a big deal. The entire I-95 mainline is built thru a marsh or over streams/rivers in that area for several miles.
Title: Re: Left-exit cloverleaf ramps
Post by: NE2 on October 15, 2013, 03:23:31 PM
It's because the I-295 split is right the fuck there.
Title: Re: Left-exit cloverleaf ramps
Post by: 1995hoo on October 15, 2013, 03:45:39 PM
Quote from: NE2 on October 15, 2013, 03:23:31 PM
It's because the I-295 split is right the fuck there.

The ramp still could have been built on the right had they wished. It just would have merged into I-95 on the left, same as it does under the existing configuration. Presuming the ramp from the other direction would have remained as is, it would have meant either having two acceleration lanes or else separating the acceleration lane for the other ramp, having the theoretical right-side ramp join that, and then having that single merged lane join I-95 on the left.

If you look at the left-side exit from southbound I-295 onto Route 141 just above there on the map, picture a mirror-image of that ramp going from 141 onto northbound I-95. That's kind of what I'm envisioning as the alternative.
Title: Re: Left-exit cloverleaf ramps
Post by: jeffandnicole on October 15, 2013, 09:45:18 PM
They could've designed it so the ramp goes in the middle of the split.
Title: Re: Left-exit cloverleaf ramps
Post by: signalman on October 16, 2013, 03:38:33 AM
Quote from: 1995hoo on October 15, 2013, 03:45:39 PM
The ramp still could have been built on the right had they wished. It just would have merged into I-95 on the left, same as it does under the existing configuration. Presuming the ramp from the other direction would have remained as is, it would have meant either having two acceleration lanes or else separating the acceleration lane for the other ramp, having the theoretical right-side ramp join that, and then having that single merged lane join I-95 on the left.
True, it could have.  However, personally I've always liked this design.  Even though I don't like left entrances onto an interstate, I've always thought it was an innovative and clever way to facilitate the movements from both directions of DE 141 to I-95 NB.
Edit to post an after thought:
Perhaps the ramp(s) were designed in order to minimize the amount of land that had to be filled.  I know the whole I-95, 295, 495, DE 141 megachange is on wetlands.  I'm not really sure if replacing wetlands that were filled in was something that was done when this was designed/built.  But if they were, perhaps the ramp configuration was chosen in order to minimize what had to be filled in and then replaced.
Title: Re: Left-exit cloverleaf ramps
Post by: 1995hoo on October 16, 2013, 09:50:06 AM
Yeah, I think it's fine too; I was just responding to NE2's comment about the I-95/295 split being right there (for whatever reason, he apparently found it offensive that someone didn't consider that).
Title: Re: Left-exit cloverleaf ramps
Post by: jeffandnicole on October 16, 2013, 11:46:15 AM
The biggest problem with the design is coming from 202 South, one enters the left side ramp then must come to an immediate yield, looking back to see if traffic is on the loop.  Many accidents have occurred due to this condition, as there's no merge lane available.
Title: Re: Left-exit cloverleaf ramps
Post by: Alex4897 on October 16, 2013, 12:37:12 PM
Quote from: 1995hoo on October 15, 2013, 02:25:39 PM
Can it be a single anticlockwise loop-around ramp without being part of a full cloverleaf? If so, there's one in Delaware: http://goo.gl/maps/PqRIz

Beat me to it.  :pan:
Title: Re: Left-exit cloverleaf ramps
Post by: Alps on October 17, 2013, 09:15:05 PM
I-94 at Telegraph Rd. in Detroit used to have an inside double-trumpet with left exits/entrances. I miss that.
Title: Re: Left-exit cloverleaf ramps
Post by: NE2 on October 17, 2013, 09:22:22 PM
Quote from: Steve on October 17, 2013, 09:15:05 PM
I-94 at Telegraph Rd. in Detroit used to have an inside double-trumpet with left exits/entrances. I miss that.
SC 31 at US 501 has an exact mirror image of it. But the loops in both are the correct (clockwise) direction - they just merge/split on the left.
Title: Re: Left-exit cloverleaf ramps
Post by: Brandon on October 18, 2013, 09:40:35 AM
Quote from: Steve on October 17, 2013, 09:15:05 PM
I-94 at Telegraph Rd. in Detroit used to have an inside double-trumpet with left exits/entrances. I miss that.

However, it did not contain left-exit cloverleaf ramps.  All ramps exited and entered Telegraph from the right.  Ditto with US-12 at I-94 in New Buffalo (Exit 4).  One of the ramps leaves wbd US-12 to ebd I-94 from the right of US-12 and enters on the left of I-94 in a similar fashion as the former ramps at Telegraph and I-94 (Exit 202).
Title: Re: Left-exit cloverleaf ramps
Post by: dgolub on October 18, 2013, 07:35:31 PM
On Long Island, the interchanges of the Southern Parkway with the Meadowbrook Parkway and the Wantagh Parkway would seem to qualify.

http://goo.gl/maps/EVDb3
http://goo.gl/maps/6z5Kb
Title: Re: Left-exit cloverleaf ramps
Post by: Kacie Jane on October 18, 2013, 07:37:36 PM
There are left exits, but the left exits aren't cloverleaf ramps.
Title: Re: Left-exit cloverleaf ramps
Post by: Revive 755 on October 18, 2013, 08:21:27 PM
Although technically not an exit, the I-270/MO 100 interchange in Des Peres, MO, has a left sided loop ramp.  It used to be a more standard right side loop until the new lanes for WB MO 100 opened.

https://maps.google.com/maps?q=des+peres,+mo&hl=en&ll=38.60326,-90.449109&spn=0.005271,0.008256&sll=42.032432,-88.091192&sspn=0.226702,0.528374&hnear=Des+Peres,+St+Louis,+Missouri&t=k&z=18 (https://maps.google.com/maps?q=des+peres,+mo&hl=en&ll=38.60326,-90.449109&spn=0.005271,0.008256&sll=42.032432,-88.091192&sspn=0.226702,0.528374&hnear=Des+Peres,+St+Louis,+Missouri&t=k&z=18)
Title: Re: Left-exit cloverleaf ramps
Post by: roadman65 on October 18, 2013, 10:03:37 PM
Quote from: jeffandnicole on October 16, 2013, 11:46:15 AM
The biggest problem with the design is coming from 202 South, one enters the left side ramp then must come to an immediate yield, looking back to see if traffic is on the loop.  Many accidents have occurred due to this condition, as there's no merge lane available.
It is a cool design despite its flaws.  True like 1995 said, it would be better if it were to the right of DE 141 to merge into the center of I-95, but being that the configuration is there it is kind of a blessing in disguise.  Having something different and out of the ordinary is good for a change.  Probably the best way to avoid the blind merge, would be to add a lane to the ramp and extend both lanes into the primary merge with I-95 where it then would drop to one and then finally none even at making the whole merge area on the freeway longer.
Title: Re: Left-exit cloverleaf ramps
Post by: pianocello on October 20, 2013, 03:45:31 PM
Looks like the ramp from EB I-94 to SB US-52 in St. Paul, MN fits the OP.
http://goo.gl/maps/W09kC
Title: Re: Left-exit cloverleaf ramps
Post by: roadman65 on October 20, 2013, 05:17:33 PM
This is not one as far as the topic goes, but it is similar as even as a right hand exit it loops around on the left.  The PA 581 and US 11 interchange near Camp Hill, PA (the S-W end of the two route concurrency) has  EB PA 581 ramp to US 11 SB exit to the right and then cross to the left side of the freeway to merge with the SB exit to US 11 SB and make a loop and return to the right side again.
https://maps.google.com/maps?q=Camp+Hill,+PA&hl=en&ll=40.243076,-76.980686&spn=0.009058,0.019741&sll=27.698638,-83.804601&sspn=10.745619,20.214844&oq=camp+h&t=h&hnear=Camp+Hill,+Cumberland,+Pennsylvania&z=16
Title: Re: Left-exit cloverleaf ramps
Post by: Alps on October 21, 2013, 08:58:19 PM
Quote from: Brandon on October 18, 2013, 09:40:35 AM
Quote from: Steve on October 17, 2013, 09:15:05 PM
I-94 at Telegraph Rd. in Detroit used to have an inside double-trumpet with left exits/entrances. I miss that.

However, it did not contain left-exit cloverleaf ramps.  All ramps exited and entered Telegraph from the right.  Ditto with US-12 at I-94 in New Buffalo (Exit 4).  One of the ramps leaves wbd US-12 to ebd I-94 from the right of US-12 and enters on the left of I-94 in a similar fashion as the former ramps at Telegraph and I-94 (Exit 202).
It did contain left-exit cloverleaf ramps. It did not contain ramps that were both left-exit AND left-entrance.
Title: Re: Left-exit cloverleaf ramps
Post by: elsmere241 on October 31, 2013, 01:44:49 PM
Quote from: roadman65 on October 18, 2013, 10:03:37 PM
Quote from: jeffandnicole on October 16, 2013, 11:46:15 AM
The biggest problem with the design is coming from 202 South, one enters the left side ramp then must come to an immediate yield, looking back to see if traffic is on the loop.  Many accidents have occurred due to this condition, as there's no merge lane available.
It is a cool design despite its flaws.  True like 1995 said, it would be better if it were to the right of DE 141 to merge into the center of I-95, but being that the configuration is there it is kind of a blessing in disguise.  Having something different and out of the ordinary is good for a change.  Probably the best way to avoid the blind merge, would be to add a lane to the ramp and extend both lanes into the primary merge with I-95 where it then would drop to one and then finally none even at making the whole merge area on the freeway longer.

DelDOT is working on that: http://deldot.gov/information/projects/i95/sr141-i95/index.shtml

The first priority will be to add that lane.
Title: Re: Left-exit cloverleaf ramps
Post by: roadman65 on November 16, 2013, 10:58:58 AM
Quote from: elsmere241 on October 31, 2013, 01:44:49 PM
Quote from: roadman65 on October 18, 2013, 10:03:37 PM
Quote from: jeffandnicole on October 16, 2013, 11:46:15 AM
The biggest problem with the design is coming from 202 South, one enters the left side ramp then must come to an immediate yield, looking back to see if traffic is on the loop.  Many accidents have occurred due to this condition, as there's no merge lane available.
It is a cool design despite its flaws.  True like 1995 said, it would be better if it were to the right of DE 141 to merge into the center of I-95, but being that the configuration is there it is kind of a blessing in disguise.  Having something different and out of the ordinary is good for a change.  Probably the best way to avoid the blind merge, would be to add a lane to the ramp and extend both lanes into the primary merge with I-95 where it then would drop to one and then finally none even at making the whole merge area on the freeway longer.

DelDOT is working on that: http://deldot.gov/information/projects/i95/sr141-i95/index.shtml

The first priority will be to add that lane.
Thanks for the link.  It looks like we do not have to wait to long for it as its states Early 2014.
Title: Re: Left-exit cloverleaf ramps
Post by: jeffandnicole on November 17, 2013, 11:43:42 AM
Quote from: roadman65 on November 16, 2013, 10:58:58 AM


DelDOT is working on that: http://deldot.gov/information/projects/i95/sr141-i95/index.shtml

The first priority will be to add that lane.

That does show US 206 on that map, right?
Title: Re: Left-exit cloverleaf ramps
Post by: Zeffy on November 17, 2013, 11:56:48 AM
Quote from: jeffandnicole on November 17, 2013, 11:43:42 AM
That does show US 206 on that map, right?

Secret extension of US 206 into Delaware?
Title: Re: Left-exit cloverleaf ramps
Post by: Truvelo on November 17, 2013, 12:14:53 PM
There's a cloverleaf 20 miles from me where all the ramps are left exits :-D
Title: Re: Left-exit cloverleaf ramps
Post by: roadman65 on November 17, 2013, 01:49:34 PM
Quote from: Zeffy on November 17, 2013, 11:56:48 AM
Quote from: jeffandnicole on November 17, 2013, 11:43:42 AM
That does show US 206 on that map, right?

Secret extension of US 206 into Delaware?
That is so funny!  It is also interesting as several miles north of Wilimington in New Jersey is that US 202 does overlap with US 206 that could mean someone's mind was not in sync.
Title: Re: Left-exit cloverleaf ramps
Post by: NE2 on November 17, 2013, 01:56:01 PM
Probably an old screenshot of a Googup.
Title: Re: Left-exit cloverleaf ramps
Post by: Mapmikey on April 07, 2014, 12:40:50 PM
Recently discovered there was a 3rd I-81/381 interchange configuration...

http://www.historicaerials.com/aerials.php?scale=3.2E-05&lat=36.6234828589419&lon=-82.1795457622069&year=T1962

I-81 NB to I-381 originally involved a left clover ramp.

By 1970, this was removed and there was no access from I-81 NB to I-381 for a number of years.

Mapmikey
Title: Re: Left-exit cloverleaf ramps
Post by: Brandon on April 07, 2014, 01:01:43 PM
Quote from: Truvelo on November 17, 2013, 12:14:53 PM
There's a cloverleaf 20 miles from me where all the ramps are left exits :-D

No shit, you don't say.  :-D

I'd guess, for you folks, it'd be more like a right-exit cloverleaf ramp.
Title: Re: Left-exit cloverleaf ramps
Post by: txstateends on April 07, 2014, 03:43:29 PM
The I-35E/I-635 interchange in NW Dallas has a left-exit cloverleaf, NB I-35E to WB I-635, added to the previously-existing interchange when I-635 was extended to DFW Airport in the late 1970s.  I never understood why a sweeping stack ramp wasn't done there instead.  I have heard that when the current 'LBJ Express' project is done between I-35E and US 75, the left-exit will remain, instead of being redone along with the other redone parts of the interchange. 
Title: Re: Left-exit cloverleaf ramps
Post by: Bitmapped on April 07, 2014, 10:31:24 PM
The US 30/SR 696 interchange by Beaverdam, OH has a left-hand loop.  I'm not really sure why ODOT went with this style of interchange: http://goo.gl/maps/Nu7o8
Title: Re: Left-exit cloverleaf ramps
Post by: PurdueBill on April 07, 2014, 10:41:00 PM
The US 30-OH 696 one isn't so much as a left-exit cloverleaf as it is an inside trumpet with movements to and from US 30 eastbound on the left, probably because of the existing ROW (from the previous US 30 expressway ending at a part-ghost interchange at Lincoln Highway, planned to swing to the northeast after passing under it) and the direction of the new road more directly east.  A traditional trumpet wouldn't have fit as well.
Title: Re: Left-exit cloverleaf ramps
Post by: english si on April 08, 2014, 10:56:57 AM
Quote from: Brandon on April 07, 2014, 01:01:43 PM
Quote from: Truvelo on November 17, 2013, 12:14:53 PM
There's a cloverleaf 20 miles from me where all the ramps are left exits :-D

No shit, you don't say.  :-D

I'd guess, for you folks, it'd be more like a right-exit cloverleaf ramp.
Heh, at least it is only 20 miles away for him: there's only three drive-on-left cloverleaves in Europe (Livingston, the Redditch one Truvelo is taking of and one on Malta). You could argue one in Plymouth and one in Kingston, but no one really counts them.

There's more loop ramps, obviously and this one at the Red Cow in Ireland (https://maps.google.com/?ll=53.320005,-6.328125&spn=0.066344,0.169086&t=m&z=13&layer=c&cbll=53.319005,-6.365244&panoid=HXZM6GOLNtnx3u-pdTmaHg&cbp=12,260.59,,0,6.72) is a right-exit one. The similar one at the N4/M50 junction to the north is more of an equal split than a right exit.
Title: Re: Left-exit cloverleaf ramps
Post by: flowmotion on April 09, 2014, 11:43:21 PM
This might count: Harrison St exit from I-80 San Francisco Bay Bridge

https://www.google.com/maps/@37.78497,-122.3928996,18z