My initial topic was split interchanges, inspired by the interchange within another interchange thread. That led me to another interesting feature that is worthy of discussion, but doesn't warrant its own topic.
First, the both interchange between I-35 and I-410 overlap with access to local roads. It's a somewhat marginal example for the other topic. The southern interchange is also an example of another interesting category, split interchanges. The same-direction movements, south to south and north to north, are handled in the northern half of the interchange, while direction changing movements are handled a mile-and-a-half to the south.
https://www.google.com/maps/@29.4634009,-98.4051755,15z?hl=en (https://www.google.com/maps/@29.4634009,-98.4051755,15z?hl=en)
This reminded me of the southern interchange between US 287 and I-35W. Northbound US 287 goes along the MLK freeway and follows a ramp to I-35W on North Freeway. At that point, the southbound side of MLK Freeway is not accessible from North Freeway; it carries traffic from Spur 280 from downtown to US 287 southbound and I-30 eastbound. Southbound US 287 traffic follows the ramp to I-30 east and then a separate ramp to the MLK freeway. I see this as a split interchange, but less dramatically so.
This leads to the other subtopic. I also wonder about the north end of the US 287 freeway. It looks like it might be a half-freeway. Spur 280 ends at I-35W. Google Maps labels the southbound lanes as 280. That isn't correct, but it points out that those lanes don't carry US 287. I looks like the southbound lanes are a ramp connecting Spur 280 with US 287. The whole road is built like a freeway, but those southbound lanes could be seen as a ramp, with the northbound lanes being a one-sided freeway. Alternatively, the whole road could be a freeway with one side carrying US 287 and the other side being unnumbered, making it a half-numbered freeway. I'd say the design is efficient, but not exactly clear if you want to understand exactly what every segment of the pavement is.
https://www.google.com/maps/@32.7527376,-97.3151392,16z?hl=en (https://www.google.com/maps/@32.7527376,-97.3151392,16z?hl=en)
Split interchanges, half-freeways, half-numbered freeways, other similar things?
I-294 (IL) / I-290 (IL) / I-88 (IL) + locals.
I-355 (IL) / I-88 (IL) + locals.
the East Los Angeles Interchange in some ways fits this descriptor: I-10 uses essentially a spur (former US 60/70/99) along the westernmost portion of the San Bernardino Freeway to reach US 101/Santa Ana Freeway entering downtown Los Angeles at the San Bernardino Split, while 10 itself merges onto I-5 briefly at a different crossing point of the Santa Ana Freeway (where the Golden State Freeway ends) -
https://www.google.com/maps/place/East+Los+Angeles,+CA/@34.039893,-118.2208473,14.5z/data=!4m5!3m4!1s0x80c2cf71ad83ff9f:0x518b28657f4543b7!8m2!3d34.0224417!4d-118.1669736?hl=en
Further east, unsigned Route 259 (former Route 18) in San Bernardino serves to provide ramp functions for Route 210 west to I-215 south and I-215 north to Route 210 east:
https://www.google.com/maps/place/San+Bernardino,+CA/@34.1383647,-117.3166391,15z/data=!4m5!3m4!1s0x80c3537de2fdb8f3:0x2867c6788c87c28d!8m2!3d34.1083449!4d-117.2897652
The post-1997 configuration of the MacArthur Maze in Oakland has the ramps from 880 north to 80 west and 80 east to 880 south separated from the main complex:
https://www.google.com/maps/place/W+Grand+Ave+%26+Maritime+St,+Oakland,+CA+94607/@37.8236773,-122.3058097,15.25z/data=!4m5!3m4!1s0x80857e30b24f4e37:0xa9f8600c0327864a!8m2!3d37.8227882!4d-122.3002701
I-55/I-90/I-94 with express/local lane merges and with local access to Cermak/22nd
https://www.google.com/maps/@41.8481869,-87.636432,15.96z?hl=en (https://www.google.com/maps/@41.8481869,-87.636432,15.96z?hl=en)
How about I-670 at I-71 in downtown Columbus, OH?
https://www.google.com/maps/@39.9771612,-82.9933152,3292m/data=!3m1!1e3?hl=en
Thanks for these examples. It's interesting to see what engineers come up with in all of the different circumstances out there.
Quote from: Chris19001 on July 31, 2018, 12:54:24 PM
How about I-670 at I-71 in downtown Columbus, OH?
https://www.google.com/maps/@39.9771612,-82.9933152,3292m/data=!3m1!1e3?hl=en
That one is confusing at first glance. I-670 follows two one-sided or half-numbered freeways and the I-71 ramps are split between them, also making it a split interchange. Also, because of the access from Cleveland Ave. to I-670 eastbound combining with the eastbound-to-northbound ramp, the I-670 eastbound lanes interchange back to themselves. That's another interesting feature there should be a name for, such as "in-interchange bypass lanes" referring to the path away from and back to the same set of main lanes, or "through-interchange self-accessing lanes" referring to the main lanes that can be left and gone back to within an interchange.
I-287, US 202/206, and US 202 in NJ.
Would I-65/I-465/I-865 on the NW side of Indianapolis count? After all, I-865 really is just a 5-mile long access ramp.