One Movement Only - Does it Exist Anywhere Else?

[hbelkins]

Spotted this on my recent trip to the northeast. Don't know if it has been mentioned upthread or not and I'm not inclined to wade through four pages to check.

http://goo.gl/maps/njRFW

Ramp to I-684 southbound.

[NE2]

Spotted this on my recent trip to the northeast. Don't know if it has been mentioned upthread or not and I'm not inclined to wade through four pages to check.

http://goo.gl/maps/njRFW

Ramp to I-684 southbound.

There's a matching northbound exit (6A).

[Ned Weasel]

This used to qualify more than it does now: southbound I-35 to 37th Avenue in Kansas City, Kansas:

http://maps.google.com/?ll=39.061841,-94.626939&spn=0.004332,0.010568&t=m&z=17

It used to be a separate ramp with (I think) its own exit number, but a few years ago, it was reconfigured to be a ramp that exits from the ramp to Southwest Boulevard and Mission Road.

[lepidopteran]

This has got to be the newest example:  NJ Turnpike, at the newly reconstructed Exit 8.  After the tollbooths, the highway continues on into the NJ-133 freeway, passing an SPUI with NJ-33 (if the overpass isn't open yet, it should be soon).  Yet there is a lone ramp from the NJ-133 lead-in, to NB Milford Rd.  I think some earlier concept diagrams had a full interchange there.

[Alps]

This has got to be the newest example:  NJ Turnpike, at the newly reconstructed Exit 8.  After the tollbooths, the highway continues on into the NJ-133 freeway, passing an SPUI with NJ-33 (if the overpass isn't open yet, it should be soon).  Yet there is a lone ramp from the NJ-133 lead-in, to NB Milford Rd.  I think some earlier concept diagrams had a full interchange there.

Eh... the intersection's 500 feet away, and this one ramp cuts off the only movement that requires two signalized left turns. Not sure I'd call it a separate interchange.

[ChoralScholar]

I know of two places in Arkansas, but one has been closed, and the exit moved up the highway.

Exit 124 on I-40 used to be a 1/4 interchange, you could get off going East, and that was it.  They built a new complete interchange about a 1/2 mile west, so this little off-ramp was destroyed.

The one that still exists is about a mile past Exit 135 on I-40, it is a 1/4 interchange where you can get on I-40 going East, and that's it.

Exit 78 on I-40 for many years was a weird 1/2 interchange where you could get off going east, and get on going west, but that was it.  They finally completed that one a few years ago.

[empirestate]

Exit 78 on I-40 for many years was a weird 1/2 interchange where you could get off going east, and get on going west, but that was it.  They finally completed that one a few years ago.

That pattern of access is quite common in half-interchanges, but how many are there where you can only get on and off in the same direction, particularly where no other nearby interchange makes up the missing movements?

[TheStranger]

That pattern of access is quite common in half-interchanges, but how many are there where you can only get on and off in the same direction, particularly where no other nearby interchange makes up the missing movements?

Anza Boulevard (Exit 419A) at US 101/Bayshore Freeway northbound in Burlingame, CA:

https://maps.google.com/maps?q=Anza+Boulevard,+Burlingame,+CA&hl=en&ll=37.587779,-122.35141&spn=0.006546,0.008626&sll=37.269174,-119.306607&sspn=13.451622,17.666016&oq=Anza+Boule&hnear=Anza+Blvd,+Burlingame,+San+Mateo,+California+94010&t=m&z=17

[roadman]

Possibly the most unquestionable example I've found yet: I-95 southbound onramp from Dedham St in, I believe, Canton, MA. And, interestingly, you can't even access 95 from westbound Dedham St, only eastbound, as left turns are prohibited, plastic bollards were installer, and U-turns are prohibited at subsequent intersections.

The rationale for this ramp was for traffic from the University Avenue area seeking I-95 south that would otherwise get on at the I-95 (or as some still call it, MA 128) University Ave interchange to use the I-95 SB ramps in Canton.  Note that MassDOT has plans to build an exit ramp from I-95 NB to Dedham Street, including providing signals at both the new I-95 northbound exit ramp and the existing entrance ramp to I-95 south.  So the Canton Street NB to I-95 SB movement will eventually be possible.

[roadman]

There is an entrance to I-84 westbound from Mashapaug Road south of Sturbridge, MA.

Note that Mashapaug Road has a full interchange with I-84 (Exit 1) north of there.  Still, it's is about three miles away from this entrance ramp, so I guess the SB on ramp at the CT border technically qualifies.

[PHLBOS]

Note that MassDOT has plans to build an exit ramp from I-95 NB to Dedham Street, including providing signals at both the new I-95 northbound exit ramp and the existing entrance ramp to I-95 south.  So the Canton Street NB to I-95 SB movement will eventually be possible.

Depending on when that new exit ramp off I-95 NB is actually built; those 2 ramps (the existing SB on-ramp and the proposed NB off-ramp) will be the new Exit 11C or Exit 25-post-MMB* Exit numbering.

* Mile-Marker-Based

[KEVIN_224]

For many years, the Christian Lane interchange with then-CT Route 72 in Berlin, CT had only one ramp from Christian Lane to then-westbound CT Route 72. Then the road became part of CT Route 9 around 1990. Soon after that, an off ramp from CT Route 9 South to Christian Lane was added. To this day, there are no off ramps from CT Route 9 North or on ramp to CT Route 9 South.

[roadman]

Note that MassDOT has plans to build an exit ramp from I-95 NB to Dedham Street, including providing signals at both the new I-95 northbound exit ramp and the existing entrance ramp to I-95 south.  So the Canton Street NB to I-95 SB movement will eventually be possible.

Depending on when that new exit ramp off I-95 NB is actually built; those 2 ramps (the existing SB on-ramp and the proposed NB off-ramp) will be the new Exit 11C or Exit 25-post-MMB* Exit numbering.

* Mile-Marker-Based

According to MassDOT's project information system, the Dedham Street ramp project is at 75% design, but is not scheduled for advertisement (letting for bids) until February of 2019.  So, based on what I've heard about the mile marker exit number implementation schedule, it's entirely possible the I-95 numbers will be converted before the new Dedham Street signs are installed.

[ChoralScholar]

Exit 78 on I-40 for many years was a weird 1/2 interchange where you could get off going east, and get on going west, but that was it.  They finally completed that one a few years ago.

That pattern of access is quite common in half-interchanges, but how many are there where you can only get on and off in the same direction, particularly where no other nearby interchange makes up the missing movements?

It just seems odd to me.  The hardest part to build is the overpass.  Once you've built the overpass, why not go ahead and make it a full interchange?

[vtk]

The overpass is already going to be there because two roads are crossing. The half-interchange arises when projected traffic pattens to and from one end of the freeway justify an interchange, but there's almost no projected traffic to and from the other end.  Such assymmetry is usually caused by a nearby large city along the freeway in one direction, and a lack of cities for a long distance in the other direction.

Sometimes half-interchanges pop up in urban areas too, usually serving commuter traffic.  They can often be placed very near another interchange without creating weaving conditions.  (See I-70 west of downtown Columbus.)

[Joe The Dragon]

There are only southbound entrances from LaGrange Road (US-12/20/45) and Archer Avenue (IL-171).

Balmoral also only had a southbound only entrance until recently when it got a northbound exit.

I-55 is the other links to LaGrange Road and Archer Avenue are

[hbelkins]

Exit 180A on I-24 in Chattanooga. It's a loop ramp from eastbound I-24 to Lee Highway and Central Avenue.

https://maps.google.com/?ll=35.02404,-85.298924&spn=0.010174,0.019119&t=m&z=16

[vtk]

In Columbus, how about I-70 E to 18th St?  If this has a mate, it's the ramp from Parsons & Main to I-71 N, but... that's to I-71 N, not I-70 W.  Opinions?

[NE2]

In Columbus, how about I-70 E to 18th St?  If this has a mate, it's the ramp from Parsons & Main to I-71 N, but... that's to I-71 N, not I-70 W.  Opinions?

Its other half is Main Street to I-71 south. In effect there's a full interchange between I-71 and Main/18th.

Also: WTF Mooberry?

[vtk]

In Columbus, how about I-70 E to 18th St?  If this has a mate, it's the ramp from Parsons & Main to I-71 N, but... that's to I-71 N, not I-70 W.  Opinions?

Its other half is Main Street to I-71 south. In effect there's a full interchange between I-71 and Main/18th.

Also: WTF Mooberry?

Ahh, you're right.  (You know, I've been looking at plans for the rebuild so much lately, I think sometimes I forget how the current interchange functions.  Or maybe it's just because I rarely get on or off there.)

And I wish I knew the story behind the naming of Mooberry St.

[Brandon]

Exit 78 on I-40 for many years was a weird 1/2 interchange where you could get off going east, and get on going west, but that was it.  They finally completed that one a few years ago.

That pattern of access is quite common in half-interchanges, but how many are there where you can only get on and off in the same direction, particularly where no other nearby interchange makes up the missing movements?

Midwest Road on I-88 is an eastbound exit/westbound entrance only interchange.  The missing movements are made up at IL-83 and Spring Road, about a mile to the east.  Interestingly enough, Spring Road is also a RIRO for westbound exit/eastbound entrance only, but some of the missing movements are made up at the IL-83 interchange about a half mile west.

[mrsman]

In West Los Angeles, I-405 has a northbound exit to Montana Ave.  No corresponding northbound entrance or southbound exit or entrance at Montana.

When the freeway was first constructed, there was a southbound exit and southbound entrance at Waterford Street that essentially corresponded to the Montana exit, but relatively recently those ramps to Waterford Street were removed due to neighborhood complaints of traffic.

[hotdogPi]

Arguably some places on US 1 between Boston and Saugus. I'm calling it arguable because some can be argued either way for if two are for the same exit or not.

[PColumbus73]

This has probably been mentioned by VTK, but the exit from OH Route 315 to Broad Street (US 40), although it is only accessible from I-670 West and US 33

[PHLBOS]

Arguably some places on US 1 between Boston and Saugus. I'm calling it arguable because some can be argued either way for if two are for the same exit or not.

Looking over US 1 (Northeast Expressway section in particular) and its ramps in that area, just about every one of them is complemented with either another ramp (in a different direction) not too far from the area. 

The reason why some of the ramp connection points with the local streets area placed as such is due to either streets being one-way or the fact that these streets pre-dated the existence of the Northeast Expressway and building conventionally-styled interchanges would've meant more land takings as well as more takings of homes and businesses.