One Ramp Interchanges

[sparker]

When I lived in Portland, I was a couple of blocks from the Taylors Ferry Road exit on NB I-5, right after it ducked under the Barbur Blvd./SW Capitol bridge at the top of the I-5 grade over the west hills.  It was an isolated single ramp emptying out onto the intersection of SW 35th Ave. and SW Taylors Ferry Road; lost count of how many times I used it!

[ran4sh]

The Downtown Connector (I-75/85) in Atlanta has a couple of these, but it could be argued that these single ramps work in combination with other partial interchanges to provide complete access.

Exit 249A, Courtland St has only a SB off-ramp (no NB ramps, no on-ramps). But when combined with the interchange of I-75/85 and A. Young International Blvd and Ellis St, it provides a ramp that is missing from that interchange.

Exit 249B, "Pine St/Peachtree St", has only a NB off-ramp (no SB ramps, no on-ramps). The adjacent interchange 249C is missing a NB off-ramp.

There's also an on-ramp from Highland Av onto I-75/85 NB, although drivers in that area could have simply used the Ellis St or J. Lewis Freedom Pkwy on-ramps.

All three of those ramps should be visible at this link https://goo.gl/maps/k6Zc1VMDJ9iKJbEn7

[skluth]

The Downtown Connector (I-75/85) in Atlanta has a couple of these, but it could be argued that these single ramps work in combination with other partial interchanges to provide complete access.

Exit 249A, Courtland St has only a SB off-ramp (no NB ramps, no on-ramps). But when combined with the interchange of I-75/85 and A. Young International Blvd and Ellis St, it provides a ramp that is missing from that interchange.

Exit 249B, "Pine St/Peachtree St", has only a NB off-ramp (no SB ramps, no on-ramps). The adjacent interchange 249C is missing a NB off-ramp.

There's also an on-ramp from Highland Av onto I-75/85 NB, although drivers in that area could have simply used the Ellis St or J. Lewis Freedom Pkwy on-ramps.

All three of those ramps should be visible at this link https://goo.gl/maps/k6Zc1VMDJ9iKJbEn7

There are plenty of places where single ramps are part of a larger complex that make a half or full interchange. That's why I didn't mention this area of I-55 in St Louis (single ramps to Potomac and Broadway and from Cherokee and President) or this single ramp to Lake St just north of the Circle Interchange. FWIW You're not the only one who posted a ramp like the Highland Av ramp. Just using your post as an example. And the Peachtree and Courtland ramps certainly qualify as one-ramp interchanges.

[ErmineNotyours]

One way to count single ramp interchanges is if your state DOT publishes official diagrams of their interchanges, and there's only one ramp on it.  See this onramp at the very north end of the infamous I-705: https://www.wsdot.wa.gov/mapsdata/tools/InterchangeViewer/pdf/SR705/705X002.pdf

[jakeroot]

One way to count single ramp interchanges is if your state DOT publishes official diagrams of their interchanges, and there's only one ramp on it.  See this onramp at the very north end of the infamous I-705: https://www.wsdot.wa.gov/mapsdata/tools/InterchangeViewer/pdf/SR705/705X002.pdf

The site of my only car accident. People merge into one lane in the on-ramp corner (as it turns into 705 from A St) rather than on the straight-away after the corner (where the two lanes actually come together). Had someone merge into me.

It can be a pretty hairy merge. Usually requires right-lane traffic to either quickly form a gap or just merge over.

[epzik8]

I seem to recall a ramp from I-95 north to Churchmans Road appearing on the 1994 edition of ADC's New Castle County, Delaware map book.

[US 89]

Questionable whether or not this counts, but the only one I can think of in Utah is I-215 northbound exit 4.

I say questionable because there is a southbound exit 4 just a bit north at 3900 South, and northbound exit 4 provides a missing ramp there... but it also serves that role for southbound exits 3 and 5, and it is even signed as "3300 South/3900 South", so you could probably argue it is its own northbound thing. For whatever reason that stretch of I-215 was built with a ton of partial interchanges and missing ramps and seems to have a very different character than most other Wasatch Front freeways.

[Bitmapped]

At Uniontown, PA, there is a single ramp from US 40 WB to Morgantown Road. All other movements are handled via US 119. https://goo.gl/maps/sQ4s7QCh7fJuYC1E6

At Cumberland, MD, there is a single ramp from I-68 WB to Seton Drive. Cumberland's main hospital used to be off this exit, which I assume is why it was built. https://goo.gl/maps/jXzdXN8bL11u2vLL9

Near Brilliant, OH, SR 7 northbound has a single ramp to Salt Run Road. There is a conventional diamond interchange about a mile north. I think this ramp was built to avoid backtracking for trucks serving a power plant. https://goo.gl/maps/7aXFns92t6Dk5NYv5

On the other side of Brilliant, there is a single ramp to SR 7 northbound. https://goo.gl/maps/9act6jbQtq1GoZn4A

[US 89]

Here's one that definitely counts: I-80 exit 352B in Wells, NV.

Looks like they just converted the original US 40 roadway into a westbound exit ramp, in addition to the full diamond at US 93 just to the west.

[jakeroot]

On BC-99 in White Rock, there is a single southbound off-ramp to southbound 152 St (Exit 8A):

https://goo.gl/maps/8rFK8UJHtEH3ncoH6

May not count as it's preceded by exit 8B, a half SPUI; I'll let others look and decide for themselves whether it's too close to the preceding interchange.

There are no ramps to/from the south at all, until you get to 16 Ave a few kilometres south.

[MCRoads]

I-64 at Great Bridge Rd is like this. Not sure how long it will remain like that though, with the new High Rise Bridge...

[sprjus4]

I-64 at Great Bridge Rd is like this. Not sure how long it will remain like that though, with the new High Rise Bridge...

No clue how I forgot about this one, though it sort of functions as the missing I-64 -> US-17 SB movement, but technically a different exit number altogether.

It will remain even when the new High Rise Bridge is complete.

[wanderer2575]

On BC-99 in White Rock, there is a single southbound off-ramp to southbound 152 St (Exit 8A):

https://goo.gl/maps/8rFK8UJHtEH3ncoH6

May not count as it's preceded by exit 8B, a half SPUI; I'll let others look and decide for themselves whether it's too close to the preceding interchange.

There are no ramps to/from the south at all, until you get to 16 Ave a few kilometres south.

One ramp aside, I've never seen a half SPUI before.  Thanks for sharing that.

[SkyPesos]

On BC-99 in White Rock, there is a single southbound off-ramp to southbound 152 St (Exit 8A):

https://goo.gl/maps/8rFK8UJHtEH3ncoH6

May not count as it's preceded by exit 8B, a half SPUI; I'll let others look and decide for themselves whether it's too close to the preceding interchange.

There are no ramps to/from the south at all, until you get to 16 Ave a few kilometres south.

One ramp aside, I've never seen a half SPUI before.  Thanks for sharing that.

Here's a half SPUI without an overpass or underpass

[ErmineNotyours]

Oddball Franken-SPUI at the very western entrance to I-90.  The only movement east of the interchange is away from the interchange, so there's no traffic from the east to take care of.  At one point, Atlantic Avenue (Edgar Martinez Way) was going to be an eastbound couplet to a full access westbound bridge north of the stadium, but those plans changed.

[kurumi]

Exit 26 on CT 9 in New Britain is a single exit ramp northbound. (It's pretty close to other interchanges, but no others are exit 26. Also, I don't know the reason for exit 28A. I don't think it got added after the CT 9 / SR 506 extension in 1986. How did it catch planners by surprise?)

[WillWeaverRVA]

I-95 southbound Exit 74B in Richmond, VA consists of a single ramp to Franklin Street and North 15th Street, with no reentry to I-95 and no direct access from the northbound side.

It's numbered 74B because the interchanges with Broad Street (US 250) (exit 74C), Franklin Street (74B), and the Downtown Expressway (VA 195) (74A) are in close proximity, it isn't actually part of either of the other interchanges.

[TheStranger]

Some more California examples:

I-5 northbound onramp from California Street, Oceanside:
https://www.openstreetmap.org/#map=17/33.18555/-117.36018

I-5 northbound onramp from Stonehill Drive, San Juan Capistrano:
https://www.openstreetmap.org/#map=16/33.4761/-117.6790

I-5 northbound onramp from Orangethorpe Avenue, Buena Park and northbound offramp to Auto Center Drive (former US 101)
https://www.openstreetmap.org/#map=17/33.85969/-117.98669

I-5 northbound exit to Crag View Drive in Shasta County
https://www.openstreetmap.org/#map=16/41.1737/-122.2899

[jakeroot]

^^^
I love OSM as much as the next guy, but it's not very helpful (at least to me) in cases like this as there is neither satellite nor street view on OSM, two things that I find helpful when looking at examples of just about anything.

(emphasis on personal opinion -- others may be perfectly happy with OSM)

[JayhawkCO]

Another one in Washington:

I-5 @ College Street in Lacey.

Chris

[andrepoiy]

There are several on the Don Valley Parkway in Toronto. The DVP going northbound from Downtown is initially entry-only (4 entrances) with no exits until the Bayview-Bloor ramp, which would be the first exit going northbound.

I have highlighted the entrances using arrows because for some reason the ramps are white coloured instead of the usual orange colour on GMaps. Second image shows the fourth entrance ramp and the Bayview Bloor Ramp.

[TheStranger]

One that I'm pretty familiar with but had forgotten until now: the Don Bosco exit off of northbound Metro Manila Skyway in Makati.  There's no corresponding onramp in any direction:

https://www.google.com/maps/@14.5453495,121.0145702,18z

[jeffandnicole]

I seem to recall a ramp from I-95 north to Churchmans Road appearing on the 1994 edition of ADC's New Castle County, Delaware map book.

If they showed a ramp there, it was printed in error.  Such a ramp didn't exist at that location.