One that comes to mind:
I-10 at the interchange with U.S. 90 and I-35 in San Antonio
Others?
Most routes that take ramps at an interchange.
The I-80 as it transistions from its concurrence with the Indiana East-West Toll Road to its concurrence with the I-94 in Northwest Indiana.
I-70 for a very short distance in Wheeling.
Quote from: NE2 on December 10, 2014, 06:20:42 PM
Most routes that take ramps at an interchange.
Maybe it's a regional thing? It's not typical in Texas, though there are some, as mentioned above.
Quote from: 02 Park Ave on December 10, 2014, 06:29:14 PM
The I-80 as it transistions from its concurrence with the Indiana East-West Toll Road to its concurrence with the I-94 in Northwest Indiana.
I-80
and I-74 through the Big X in the Quad Cities.
Quote from: US81 on December 10, 2014, 06:38:54 PM
Quote from: NE2 on December 10, 2014, 06:20:42 PM
Most routes that take ramps at an interchange.
Maybe it's a regional thing? It's not typical in Texas, though there are some, as mentioned above.
Not too many Interstates in Texas take ramps. The only two obvious examples I can find are I-10 in San Antonio (twice, though one is more of an equal split) and I-410 in San Antonio (which definitely gets down to one lane at the north split, at least for now).
Quote from: Brandon on December 10, 2014, 06:59:44 PM
Quote from: 02 Park Ave on December 10, 2014, 06:29:14 PM
The I-80 as it transistions from its concurrence with the Indiana East-West Toll Road to its concurrence with the I-94 in Northwest Indiana.
I-80 and I-74 through the Big X in the Quad Cities.
And I-74 just outside the Quad City Airport.
Quote from: US81 on December 10, 2014, 06:38:54 PM
Quote from: NE2 on December 10, 2014, 06:20:42 PM
Most routes that take ramps at an interchange.
Maybe it's a regional thing? It's not typical in Texas, though there are some, as mentioned above.
Probably more common in the East due to a confluence of factors. Many eastern states were building substandard freeways prior to the 1956 Act, and in some cases, Interstate designations were strung along multiple existing roads. A prime example is I-83 in Harrisburg, which one-lane exits itself twice in a five-mile span as it snakes from the former US 111 expressway to the Harrisburg Expressway and finally to the prior Bypass 230 expressway. Coupled with the East's typically denser urban cores and higher land costs–and tapped out state highway departments that had shouldered a great deal of construction costs prior to the Interstate's 90% federal funding scheme–building proper thru movements was either not feasible or not a priority.
I-75 at I-640 and I-275 in Knoxville. I've seen traffic dog-knotted pretty badly southbound at the one-lane ramp that traffic has to use to stay on 75.
I-55 and the Poplar st Bridge in St Louis.
Quote from: pianocello on December 10, 2014, 07:46:04 PM
Quote from: Brandon on December 10, 2014, 06:59:44 PM
Quote from: 02 Park Ave on December 10, 2014, 06:29:14 PM
The I-80 as it transistions from its concurrence with the Indiana East-West Toll Road to its concurrence with the I-94 in Northwest Indiana.
I-80 and I-74 through the Big X in the Quad Cities.
And I-74 just outside the Quad City Airport.
And I-74 (again) at the northwest split between I-55 and I-74.
Then there's I-72 at I-55 (Clear Lake Ave) in Springfield.
And I-72 again near Hannibal at the split with I-172.
Need I mention I-39 at US-20 in Rockford?
Quote from: NE2 on December 10, 2014, 06:20:42 PM
Most routes that take ramps at an interchange.
OK, so how about those that go to one lane, but don't appreciably change direction through the interchange? In other words, they form the through route both numerically and geometrically (meaning that the predominant flow of traffic takes a turn through the interchange, and changes numbers as it does so).
I'm old enough to remember when the southern split of I-75 and I-64 near Lexington was one lane in each direction. The traffic backups on the day before Thanksgiving and right before Christmas were legendary. They added a second lane around 1979-80 and a third lane at some later date.
I-76 Eastbound at exit 326 as it leaves the PA turnpike is briefly one lane before splitting into 2. I-76 Westbound is one lane for the entire loop as it enters the turnpike at the same location.
Quote from: US81 on December 10, 2014, 06:38:54 PM
Quote from: NE2 on December 10, 2014, 06:20:42 PM
Most routes that take ramps at an interchange.
Maybe it's a regional thing? It's not typical in Texas, though there are some, as mentioned above.
I'm going to apologize right now. Even with the OP example, an interchange I have driven through many times, I didn't stop to think. "Taking ramps" just didn't evoke "oh, like TOTSO" but it should have. I pictured the one lane going straight through the intersection with the other lane(s) exiting, say in a cloverleaf, and could think of a few historic examples but none extant.
I am renewing my vow not to post when sleep-deprived.
...and now, returning to the scheduled thread already in progress....
Quote from: 02 Park Ave on December 10, 2014, 06:29:14 PM
The I-80 as it transistions from its concurrence with the Indiana East-West Toll Road to its concurrence with the I-94 in Northwest Indiana.
For quite awhile I-80 has actually been zero lanes going westbound at that location, since the ramp was closed and then demolished. The detour goes down to one lane across multiple ramps from the ITR to I-65 south. They've promised to rebuild the WB ramp, though I'm sure it will remain one lane.
I-70 at the northeast corner of the KC Downtown Loop. Eastbound, it keeps one lane, and though the way the interchange is built has it configured like an exit (one lane, right exit,) it is signed as the "through" movement. (No exit number - I-35 here is signed as the exit.) In the opposite direction, it has two lanes for a brief distance, but narrows to one before merging with I-35.
Quote from: hbelkins on December 10, 2014, 08:36:32 PM
I-75 at I-640 and I-275 in Knoxville. I've seen traffic dog-knotted pretty badly southbound at the one-lane ramp that traffic has to use to stay on 75.
Hey, before that bypass with the colorful overpasses was built (for the 1982 World's Fair?), I-75 NB traffic had to negotiate a tight cloverleaf ramp in the downtown area. Probably easy-to-miss as well.
Also on I-75, at least one direction had only one through lane at the T-interchange with I-280 in Toledo. Not sure when that was improved.
I-70 westbound at I-71, east end of the overlap. Of four lanes, the right two go to I-71 north, then the right lane of the two remaining is exit-only for the new downtown exit. I-70 westbound is then a single lane for about a half mile before I-71 southbound contributes a couple of lanes on the left.
The furthest north portions of I-35W at the E/W split of I-35 in Denton, TX are one lane in each direction for a short distance. This may not last much longer because the interchange is being rebuilt.
I-35 at the I-40/I-235 interchange in downtown OKC uses a pair of one lane ramps.
I-49 follows a pair of one-lane ramps at each of its interchanges with I-44 near Joplin.
I-43 Hale interchange SW of Milwaukee: https://www.google.com/maps/@42.9612155,-88.0391969,3a,75y,40.88h,84.3t/data=!3m4!1e1!3m2!1sxQZdpiC77dRlo_2SU_TTJw!2e0
- Eastbound I-94 in Northbrook, Illinois just before where the road merges with US 41
- I-90 between where it branches off of the Ohio Turnpike (with I-80) and the Route 2 freeway in Elyria, Ohio
- Then there's the Ohio Turnpike I-76 and I-80 interchange where both interstates are reduced to one lane with numerous loop ramps and a toll booth near Youngstown
I-79 at both of it's interchanges with I-70 in Washington, PA (excludes NB at the Southern/Eastern interchange as that just recently got a new 2 lane mainline flyover).
I-73 at I-85/US 421/US 220 interchange south of Greensboro. Both I-73 North and South takes one lane ramps when they enter (I-73 North) or exit the Loop (I-73 South). I-73 and I-85 does not merge, but parallel each other at that location.
I-74 west bound at I-275 reduces to one lane. It looks like this wasn't always the case.
I swear to Christ somewhere in LA, I-5 South drops to one lane but I cannot figure out where. Perhaps I'm delusional.
Quote from: dfwmapper on December 12, 2014, 05:33:37 PM
The furthest north portions of I-35W at the E/W split of I-35 in Denton, TX are one lane in each direction for a short distance. This may not last much longer because the interchange is being rebuilt.
I-35 at the I-40/I-235 interchange in downtown OKC uses a pair of one lane ramps.
I-49 follows a pair of one-lane ramps at each of its interchanges with I-44 near Joplin.
I-35W (southbound) at the Hillsboro split, although that is being reconstructed, too.
Quote from: jakeroot on December 13, 2014, 01:03:34 AM
I swear to Christ somewhere in LA, I-5 South drops to one lane but I cannot figure out where. Perhaps I'm delusional.
East LA Interchange downtown (with I-10, US-101 and SR-60.)
I am fairly certain that I-5 South never narrows down to less than 2 lanes. I closest instance I can think of is where I-5 South and CA-60 East branches off to the left from I-10 west. What they did there was add a second exit lane over a previous gore area, that I never use because it is way too rough.
Quote from: US81 on December 13, 2014, 08:16:12 AM
I-35W (southbound) at the Hillsboro split, although that is being reconstructed, too.
The rebuild of the Hillsboro split was finished in 2009.
Quote from: dfwmapper on December 13, 2014, 03:55:04 PM
Quote from: US81 on December 13, 2014, 08:16:12 AM
I-35W (southbound) at the Hillsboro split, although that is being reconstructed, too.
The rebuild of the Hillsboro split was finished in 2009.
It's hard to notice that a particular segment is done with all the ongoing construction on I-35, but I stand corrected.
(Wow, was it really that long ago? I know I've been thru there since then several times. Senility, I guess)
Also I-35W ends there, so it doesn't count.
Both Mixmasters in Des Moines (the I-35/80/235 junctions) feature these: I-35 on the east end, and I-80 on the west. The east mixer is interesting southbound because the obvious thru movement (I-35 SB -> I-235 WB) is signed as a Left exit. (Street View) (https://www.google.com/maps/@41.6604904,-93.5757915,3a,75y,196.12h,92.3t/data=!3m4!1e1!3m2!1sAiAQ4ydM_ELT_sBG15LALw!2e0)
Quote from: pianocello on December 13, 2014, 10:06:39 PM
The east mixer is interesting southbound because the obvious thru movement (I-35 SB -> I-235 WB) is signed as a Left exit. (Street View) (https://www.google.com/maps/@41.6604904,-93.5757915,3a,75y,196.12h,92.3t/data=!3m4!1e1!3m2!1sAiAQ4ydM_ELT_sBG15LALw!2e0)
Blame the MUTCD.
I-74 where it splits off from I-465 on the east side of Indianapolis. Used to be the same on the west side until the interchange was rebuilt a couple years ago. I-74 shows up a lot on this list.
Are there any cases where it clearly doesn't take a ramp or merges equally with another route (such as I-74 west at I-275), but takes the obvious straight movement yet still goes down to one lane? For example, SR 125 south at I-8 in San Diego would count if the former were an Interstate.
I-705 in Tacoma is one lane for about 500 yards (gore to gore) as exit and entrance ramps split and join respectively ... the thru lane is on the right:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.interstate-guide.com%2Fimages705%2Fi-705_wa_st_06.jpg&hash=d60f599bbc7e1119207122c80680821da6d930cd)
Image from Interstate-Guide.com (http://www.interstate-guide.com/i-705_wa.html)
Fucking hell nevermind, it's a 3di.
Quote from: NE2 on December 14, 2014, 01:37:40 AM
Are there any cases where it clearly doesn't take a ramp or merges equally with another route (such as I-74 west at I-275), but takes the obvious straight movement yet still goes down to one lane? For example, SR 125 south at I-8 in San Diego would count if the former were an Interstate.
It was already mentioned in this thread, and I'm not sure whether it meets the OP's definition of "major interchange," but I-70 and NB WV 2 (Wheeling) is the only one that comes to mind. I'm pretty sure the lane reduction was made for the sake of avoiding sudden merges at the bridge and tunnel approaches, given the short distance (but that's probably old news to everyone here).
Damn, forgot about I-70 Wheeling.
I-8 eastbound drops to a single lane just before it merges with the ramp from I-5 southbound in San Diego.