What are some notable redundant interchanges you've come across?
This can be a single interchange that for instance has a cloverleaf but also a left turn ramp from the other side that goes in the same direction. It can be an interchange that has something unnecessary on it like a slip ramp that leads to the same road. Or an interchange boondoggle like that one in Tennessee on I 75 that goes nowhere (forgot what it was called).
Or it can be a pair of interchanges on two nearby freeways that go to the same road and aren't really necessary because they are super close together.
A good example of this would be SR 138's diamond interchanges with I 75 and I 675 in southeast Atlanta near Stockbridge. There really is no point on having those two interchanges since both I 675 and I 75 intersect after they both intersect with SR 138. Especially the southbound SR 138 to I 675 ramp and northbound I 675 to SR 138 ramp.
Well SB I-75 at the northern I-285 exchange near Smyrna has two ramps to I-285 due to a previous ramp merging after the first ramp.
https://goo.gl/maps/SdovWEmMRkSmUk5X6
https://goo.gl/maps/WUzfdPRTrbVx2CtZA
I-95 NB has two ramps to I-195 east in Miami to avoid a weaving situation.
https://www.flickr.com/photos/54480415@N08/51544148721/in/album-72157633808337073/
https://www.flickr.com/photos/54480415@N08/51543388957
US 40 eastbound at MD 22 in Aberdeen has possible movements to MD 22 east from each ramp, the eastbound and westbound ones.
I-25, at the Park Ave / Coors Field /38th Ave exit (first one S of I-70, SB.. exit 213 maybe?)
You can juke left, and take a flyover to Park Ave, or juke straight, and come down to Fox St, take a left, and it becomes Park Ave. The flyover you missed, comes in from the right.
https://goo.gl/maps/Nr22AwCAQRNpmp1G6 (https://goo.gl/maps/Nr22AwCAQRNpmp1G6)
DE 1 has two northbound ramps to I-95 northbound: the flyover ramp that splits from the left before the DE 7 interchange and a ramp that splits from the right past DE 7 and Mall Road, the latter ramp allows access to I-95 northbound from DE 7 and the Christiana Mall
I-40 has two ramps to NC 54: 273A is a cloverleaf to NC 54 west; 273B leads to a stoplight at NC 54, where you can make a left turn onto NC 54 west. Usually, 273A is free flowing onto NC 54, but sometimes there is a backup on the 273A ramp and taking 273B can be faster.
US 3/Everett Turnpike in Nashua has two ramps onto the Circumferential Highway with one coming off the on ramp from Spit Brook Rd and another one actually being the exit off the Everett Turnpike.
Every second interchange in the state of California. They don't seem to understand the meaning of "limited-access freeway".
Does this count?
(https://i.imgur.com/aSfnwuE.png)
Exits 361 and 363 on I-70 in Colorado at Limon.
US 119 northbound to I-64 in Charleston, WV. There's a right-exit flyover ramp and also a left-turn ramp.
Quote from: CtrlAltDel on June 06, 2023, 12:03:22 PM
Does this count?
(https://i.imgur.com/aSfnwuE.png)
Exits 361 and 363 on I-70 in Colorado at Limon.
Absolutely.
Quote from: Georgia Guardrail on June 06, 2023, 02:02:17 PM
Quote from: CtrlAltDel on June 06, 2023, 12:03:22 PM
Does this count?
Exits 361 and 363 on I-70 in Colorado at Limon.
Absolutely.
Yep. It should be the posterchild for this thread.
Exits 26 and 27 on I-295 North both lead to I-76. I understand this is a temporary (if long-term) situation due to construction, but what exactly is the point of having them both open right now?
Quote from: CtrlAltDel on June 06, 2023, 12:03:22 PM
Does this count?
(https://i.imgur.com/aSfnwuE.png)
Exits 361 and 363 on I-70 in Colorado at Limon.
The fact that I recognized this as Limon before reading the rest of the post tells me that I spend too much time on here.
I posted this in another thread, but with the construction of roundabouts some years ago, there is a redundant loop ramp from nbd M-53 to 26 Mile Road in Washington MI. The exits are still signed as 23A to ebd and 23B to wbd, but either ramp can be used to either direction. I was confused when I drove through there because my GPS told me to take the ebd exit even though I wanted to go west, as not using the loop ramp was a few hundred feet shorter.
https://goo.gl/maps/iZSiVbKie3xbHAxL8
There is a redundant loop ramp from sbd Lahser Road to ebd I-696 in Southfield MI. Could just as easily turn left and use that ramp (although might have to yield for oncoming traffic). I wonder if that was done because it's a double left-turn lane for the upcoming M-10 interchange.
https://goo.gl/maps/RCjdRD82PCTJ2ATk7
And in Farmington Hills MI, after ebd I-696 exits to ebd M-5, there is a redundant loop ramp back to I-696. Maybe that doesn't count because it's intended for sbd M-5 traffic to access I-696.
https://goo.gl/maps/1cqhfW4ssMzTkqtd9
Pavement conditions and traffic aside, one could argue the six freeway-to-freeway interchanges in downtown Detroit are close together enough to be considered redundant.
https://goo.gl/maps/KT5XxYxGHoLKAmiQ8
The Aerojet Road exit off of US 50 in Rancho Cordova, just east of the Hazel Avenue exit - both of which provide access to Folsom Boulevard.
https://www.google.com/maps/place/Aerojet+Rd+%26+Folsom+Blvd,+California+95742/@38.6310543,-121.2180288,16z/data=!4m6!3m5!1s0x809ae6f883b064fb:0xc776ebde46fc80a3!8m2!3d38.631926!4d-121.2087913!16s%2Fg%2F11gdzz9j3n?entry=ttu
(This actually was useful when a friend and I missed a turn to a shopping center a week ago)
---
No longer in use, but from the 1960s to 1994, I-10 had two ways to reach the southbound Santa Ana Freeway in East Los Angeles:
1. Use the flyover that carries I-10 to the southbound Golden State Freeway, then follow I-5 through the East Los Angeles Interchange to the Santa Ana Freeway
2. Use the flyover at the San Bernardino Split from I-10 west to US 101/Santa Ana Freeway south, and continue as the designation becomes I-5 a mile later
Interestingly, the redundant northbound to eastbound movements still exist to this day: I-5 to I-10 east and I-5 to US 101 to I-10 east.
https://www.google.com/maps/place/Boyle+Heights,+Los+Angeles,+CA/@34.0429127,-118.2270602,14z/data=!4m6!3m5!1s0x80c2c6029c9a59e9:0xec9ea70c76393a94!8m2!3d34.0297895!4d-118.2117257!16zL20vMDIzN204?entry=ttu
---
Nearby the above example is one that actually was useful years ago to bypass construction traffic:
from I-710 north, one can get to I-5 (and US 101 eventually) north through the following nearby methods:
1. Directly to I-5 north
2. Via Route 60 west
3. Via I-10 west
https://www.google.com/maps/place/Boyle+Heights,+Los+Angeles,+CA/@34.0407079,-118.1907538,13z/data=!4m6!3m5!1s0x80c2c6029c9a59e9:0xec9ea70c76393a94!8m2!3d34.0297895!4d-118.2117257!16zL20vMDIzN204?entry=ttu
NY 31 WB has two ramps to I-590 south. The one that's a left turn was added in recent years at the same time they reduced the EB direction from three lanes to two from I-590 to NY 65 and adding a light there; previously, that ramp only served EB traffic.
Not sure if this would qualify, but I'll explain: I-65 North at I-64/I-71 in Louisville right before going over into Indiana.
You can take the exit, which leads you to a ramp from a previous exit's feed-on. Stay in the far right lane, and you end up back on I-65 on the Lincoln Bridge going into Indiana and over the Ohio River. Apparently easier access to Exit 0, as Waze told me, but you could have gotten over however many lanes without much of a problem all the same.
https://www.google.com/maps/place/West+Bend,+WI/@43.281123,-88.1862574,2143m/data=!3m1!1e3!4m6!3m5!1s0x880458d418f43ee9:0xd0ca372bda321e30!8m2!3d43.4252776!4d-88.1834277!16zL20vMDFtbnli?entry=ttu
Just north of the I-41/US-45 split near West Bend, WI WI 145 interchanges with both freeways.
Quote from: milbfan on June 06, 2023, 10:52:57 PM
Not sure if this would qualify, but I'll explain: I-65 North at I-64/I-71 in Louisville right before going over into Indiana.
You can take the exit, which leads you to a ramp from a previous exit's feed-on. Stay in the far right lane, and you end up back on I-65 on the Lincoln Bridge going into Indiana and over the Ohio River. Apparently easier access to Exit 0, as Waze told me, but you could have gotten over however many lanes without much of a problem all the same.
Northbound I-55 in Illinois at the Mississippi River is similar. Exit 1 leads to IL-3, Tudor Avenue, and Fourth Street, before merging back onto I-55. It comes in handy since in Saint Louis, I-55 merges onto I-44, right at the beginning of the bridge, and it can be difficult to get over to stay on "official" I-55 if there's traffic.
(https://i.imgur.com/BZJAM2R.png)
Also similar to this is exit 137 on westbound I-88 in the Chicago suburbs. It leads to a loop ramp to IL-83 south, but it branches to lead right back to I-88. Traditionally, I take this when I'm going to my sister's house on Christmas Eve. (I couldn't tell you why.)
(https://i.imgur.com/NvKYRTk.png)
I suppose that any CD setup would also work, but these are somewhat unique.
Quote from: bzakharin on June 06, 2023, 04:22:17 PM
Exits 26 and 27 on I-295 North both lead to I-76. I understand this is a temporary (if long-term) situation due to construction, but what exactly is the point of having them both open right now?
During the current construction, they decided to keep both access points since it was determined one would frequently need to be closed due to construction activity.
What NJDOT *should* have done at that point was provide advanced signing informing motorists the optimal exit to take if one wanted to ultimately go to the Walt Whitman Bridge (Exit 26) or US 130/I-676 (Exit 27). And provided better signage based on when one of the exits is closed due to that construction activity.
Instead, NJDOT did none of that, and instead provided motorists with BGS signage at the 2 mile, 1 mile, and 1/2 mile points informing them to take Exit 26 for I-76 to I-676. Then at the 500 Foot point, they provided some confusing signage which informs motorists to take Exit 26 for I-76 to I-676 while adding a pull-thru sign with a vague reference that suggests continuing on I-295 will take motorists to I-76: https://goo.gl/maps/PTdyEGGSZVjeqTvx7 , then just as they reach the Exit 26 decision point, they are greeted with a sign informing them to take Exit 27 for I-76 to I-676, omitting the overhead BGS for Exit 26: https://goo.gl/maps/ujamfsnZHRdaWjGP9 .
Everyday motorists know what to do. Motorists unfamiliar with the area are seen quickly cutting across the gore point at the last moment trying to figure out what to do.
Doesn’t US 29 in Elliicot City, MD have two ramps to I-70 westbound? If I recall there is one on the right and one on the left heading north.
Edit: According to this map. Yes
https://www.google.com/maps/place/Ellicott+City,+MD/@39.2983254,-76.8265766,17.67z/data=!4m6!3m5!1s0x89c8202b017c6f07:0x71219558c723760!8m2!3d39.2673283!4d-76.7983067!16zL20vMHR2eTI?entry=ttu
https://goo.gl/maps/TtWYVHcjQA8RPGGR9
GSV shows them both.
US-460 at I-81 in Christiansburg has two redundant ramps. Loop ramps exist for traffic on US-460 East towards I-81 North, and for I-81 North towards US-460 West, however traffic can also use the outer ramps by turning left, as turn lanes and a median break allow.
https://maps.app.goo.gl/xMY8VZaSa3kSkXxU7?g_st=ic
The infamous South of The Border Interchange at the NC-SC Line has two SB I-95 ramps to US 301/501 SB. You have the loop ramp and the outer as well where you can turn left at the end of the ramp.
Billboards for the Tourist Trap approaching the exchange would inform motorists that SOB was " The Next 2 Exits."
https://www.google.com/maps/place/Dillon,+SC+29536/@34.5032383,-79.3106026,16.41z/data=!4m6!3m5!1s0x89aacab066ffbc27:0x658bc9252fd76235!8m2!3d34.4165505!4d-79.3711579!16zL20vMF9sZDA?entry=ttu
Stand corrected. For both NB and SB ramps allow left turns.
https://goo.gl/maps/EKMJGx11by6X4iFP6
I don't think Washington has any.
Disclaimer: While I have driven all interstates and US highways in Washington, I haven't driven all state routes in Washington. So, this is just what I think.
In Bloomington, MN when the I-494/TH 77 interchange was upgraded in the 90s as part of the construction of the Mall of America, a new flyover with additional feeder ramps from the streets serving the mall was built from northbound 77 to westbound 494. However, the existing NB/WB loop of the cloverleaf was kept as the HOV/carpool ramp and recently served as the "detour" when the flyover ramp was closed for construction.
When I drove to Naperville IL a couple weeks ago, my GPS routed me off I-294 to sbd I-55 and then right back onto I-294. I'm sure this isn't intended to be redundant, but the location of the ramps does it for this movement.
(https://i.imgur.com/iqmZ0fY.png)
Quote from: wanderer2575 on June 07, 2023, 09:57:01 AM
When I drove to Naperville IL a couple weeks ago, my GPS routed me off I-294 to sbd I-55 and then right back onto I-294. I'm sure this isn't intended to be redundant, but the location of the ramps does it for this movement.
Similarly, you can get off northbound I-355 to get on eastbound I-88 and then back on to northbound I-355:
(https://i.imgur.com/oEE2Gr0.png)
Also, this used to be exit 218 on I-40 in New Mexico at Clines Corners, with direct and indirect access to that gas station at the upper left, but the direct access was removed in about 2016.
(https://i.imgur.com/gRdRzBt.png)
Quote from: CtrlAltDel on June 06, 2023, 12:03:22 PM
Does this count?
(https://i.imgur.com/aSfnwuE.png)
Exits 361 and 363 on I-70 in Colorado at Limon.
What was the logic for building this as two full diamonds instead of half diamonds? Seems wasteful and redundant to me.
A similar thread I did last year, for reference.
https://www.aaroads.com/forum/index.php?topic=30920.msg2701247#msg2701247
The one in Taylor in the OP of that thread and the stack overlaid on a cloverleaf in El Paso are probably my favorite redundant interchanges.
CoreySamson, thanks for posting that link. I was getting ready to post the same two locations I had mentioned in that thread (not remembering that thread existed), but since you linked it, I'll just quote what I posted there. Regarding the method of going from I-95 to the Beltway that involves circling around past the park-and-ride, I remember we went that way once when I was a kid back before the flyover ramp existed–the only options were the loop ramp or going past what is now the park-and-ride. Normally we went the other way around the Beltway, but for that particular trip we were going around the eastern side. My mother got confused by the signs, so I gave my father directions to go the longer way around what is now the park-and-ride and when we followed it, his reaction was along the lines of, "What kind of screwy route is this?!" To which I replied, "We've never gone this way before and I wanted to see where it went." (This was probably in the late 1970s or very early 1980s.) I don't think he was all that amused, though it didn't really matter.
Quote from: 1995hoo on January 25, 2022, 03:19:12 PM
In Maryland, southbound I-95 has three (https://www.google.com/maps/@39.0226561,-76.9521896,15.29z) different ways to access the Inner Loop of the Capital Beltway–a two-lane flyover (the newest of the three ramps), a cloverleaf-style loop ramp that was the original primary route and is now used primarily for traffic wishing to access the Beltway's exit to US-1 (which is inaccessible via the flyover), and a ramp that's accessed by circling past the park-and-ride lot at the stub end of where the road was never completed. That third ramp would have been the northbound I-95 ramp to the Inner Loop had I-95 been constructed as planned.
In Virginia, the Inner Loop of the Beltway used to have two separate ramps to westbound I-66: Exit 9A (later 49A) was a left-side exit and Exit 9C (later 49C) was a right-side loop-around. The reason for the duplicate ramps was primarily to eliminate the danger caused by requiring traffic entering from US-50 just to the south to cut across four lanes of traffic to the left-side exit in a short distance, but in practice it didn't help because people cut across anyway. The duplication no longer exists because HO/T lane construction restricted the left-side exit to HO/T traffic and the general-purpose lanes now have only one ramp available.
Then there is this oddity (https://www.google.com/maps/@44.7529536,-75.4914792,14.62z) from southbound 416 to westbound 401 in Ontario. My sat-nav wanted me to take the longer way where you exit 416 to 16, then exit that to the right onto 401. I followed it just to see if there was any particular reason to go that way. There wasn't. Maybe whoever programmed the sat-nav knew the BGS for the longer route says "TO/VERS U.S.A." and got confused when programming it.
Quote from: hbelkins on June 07, 2023, 12:37:41 PM
Quote from: CtrlAltDel on June 06, 2023, 12:03:22 PM
Does this count?
(https://i.imgur.com/aSfnwuE.png)
Exits 361 and 363 on I-70 in Colorado at Limon.
What was the logic for building this as two full diamonds instead of half diamonds? Seems wasteful and redundant to me.
There was an entire thread on that subject: https://www.aaroads.com/forum/index.php?topic=24830.0 (https://www.aaroads.com/forum/index.php?topic=24830.0)
Similar to the US 29/I-70 & US 460/I-81 examples upthread, Shawan Rd WB has both a loop ramp as well as a left-turn (https://www.google.com/maps/@39.4951642,-76.6667644,631m/data=!3m1!1e3?entry=ttu) to access I-83 SB at exit 20 in the northern Baltimore suburbs.
Quote from: 1995hoo on June 07, 2023, 01:35:14 PM
Regarding the method of going from I-95 to the Beltway that involves circling around past the park-and-ride, I remember we went that way once when I was a kid back before the flyover ramp existed–the only options were the loop ramp or going past what is now the park-and-ride. Normally we went the other way around the Beltway, but for that particular trip we were going around the eastern side. My mother got confused by the signs, so I gave my father directions to go the longer way around what is now the park-and-ride and when we followed it, his reaction was along the lines of, "What kind of screwy route is this?!" To which I replied, "We've never gone this way before and I wanted to see where it went." (This was probably in the late 1970s or very early 1980s.) I don't think he was all that amused, though it didn't really matter.
That park-and-ride trick you describe comes in handy during rush hour when traffic tends to crawl across much of the length of the flyover leading into the merge with I-495.
Quote from: paulthemapguy on June 06, 2023, 11:53:15 AM
Every second interchange in the state of California. They don't seem to understand the meaning of "limited-access freeway".
That's "Every second URBAN interchange on OLDER freeways in California". On newer and rural freeways, take I-280 (or even CASR-87), for instance, interchanges are all a couple miles apart.
Quote from: Amaury on June 07, 2023, 01:41:21 AM
I don't think Washington has any.
Disclaimer: While I have driven all interstates and US highways in Washington, I haven't driven all state routes in Washington. So, this is just what I think.
There are a few that might count. SR 512 around the South Hill Mall has a redundant set of ramps due to the 90-degree turn. The Eastgate interchange on I-90 has an extra set of ramps to 161st Avenue SE that are utterly pointless because of the existing entrance/exit at 166th.
A few dogbone interchanges have redundant slip ramps to bypass a very simple in-roundabout move (such as I-5 at Cowlitz Way, I-82 at Valley Mall, or I-90 at SR 902). Another one, I-90 at Grove Road, has cloverleaf ramps that bypass a roundabout with a valid entrance (see here (https://www.google.com/maps/@47.6188002,-117.5022648,367m/data=!3m1!1e3?entry=ttu)).
Arguably the three interchanges at Snoqualmie Summit are redundant to each other as well.
The Arlington Expressway in Jacksonville has an exit onto University Blvd with separate ramps to go south or north, but then a few hundred feet down the road there's a pair of off-ramps to the frontage road, one of which lets you turn around and head north on University Blvd: https://goo.gl/maps/GZzaMchWjnptYx7A6
Long-term the plan is to remove the ramp. People have also discussed just removing The Arlington Expressway altogether. On one hand, it's quite outdated and doesn't save that much time since it's only a couple miles long and dumps traffic onto a surface road (Atlantic Blvd). But on the other hand it's quite....quirky so I'd be sad to see it go.
A couple in CT:
I-84 West to I-384 East. Conventional method: Exit 59. Unconventional: Access via Exit 62/60 c/d road.
US 5/CT 15 South to I-91 South. Conventional method: Exit 86. Unconventional: Access via Exit 87 and stay on ramp rather than exiting onto Airport Rd.
I-5 south to Laval Road has two ramps for each direction, but the westbound ramp is redundant since it's possible to turn left to westbound Laval Road using the eastbound ramp too.
SB 405 at the Century/Imperial exits. The east-west designations are for show, as you can access either road in any direction from any ramp.
NB 15 and 215 both access Murrieta Hot Springs Road with complete freedom of movement.
https://www.google.com/maps/@30.3552199,-81.5548173,16.13z?entry=ttu
Merril Road EB has two exits from I-295 SB. One from the previous exit via FL 113 and the second (actual) ramp to Merrill Road that has a signalized intersection to allow left turns.
https://goo.gl/maps/7nUrdWjvw1nvhnLC8
Funny thing is the second ramp is signed for WB while EB gets signed on the previous ramp wit FL 113.
I-295 SB to I-64 EB has two ramps: a loop ramp from the original cloverleaf interchange plus a flyover that was added in a later project. I'm not really sure why they decided to keep the loop ramp open after the flyover opened.
Quote from: roadman65 on July 02, 2023, 03:03:13 PM
https://www.google.com/maps/@30.3552199,-81.5548173,16.13z?entry=ttu
Merril Road EB has two exits from I-295 SB. One from the previous exit via FL 113 and the second (actual) ramp to Merrill Road that has a signalized intersection to allow left turns.
https://goo.gl/maps/7nUrdWjvw1nvhnLC8
Funny thing is the second ramp is signed for WB while EB gets signed on the previous ramp wit FL 113.
Bonus points for this one, because if the USGS topos on Acme Mapper can be trusted, this interchange had the same redundancy in its previous design, before FL 113 was turned into a freeway. The SPUI that's now at FL 113 and Merrill Road was a four-way intersection, but the Exit 46 ramp (Merrill Road West) from I-295 SB still had a left-turn available to Merrill Road EB.
In both of these configurations, I can't see any reason why the Exit 46-to-Merrill EB left turn is needed. Why not make the end of that ramp right-turn-only, potentially allowing Merrill Road WB to be free-flowing through that intersection rather than needing a stoplight for the left turn out of the exit ramp? Unlike some examples in this thread, there is not even a single business or driveway between the two ramps, so there is not a single thing that can be accessed uniquely from a left turn from the Exit 46 ramp.
I-880 NB at Dixon Landing Road, Milpitas: https://goo.gl/maps/i4ZEMkQVMr2Duf287
The "Dixon Landing Road West" loop ramp offers a superfluous left turn onto DLR East; and with two left turns you could use the "East" exit to access DLR west.
The NE quadrant ramp pair could be a RIRO on Dixon Landing Road; but instead it's part of a full 4-way intersection (except no left turn from DLR east onto I-880 north).
Quote from: roadman65 on July 02, 2023, 03:03:13 PM
https://www.google.com/maps/@30.3552199,-81.5548173,16.13z?entry=ttu
Merril Road EB has two exits from I-295 SB. One from the previous exit via FL 113 and the second (actual) ramp to Merrill Road that has a signalized intersection to allow left turns.
https://goo.gl/maps/7nUrdWjvw1nvhnLC8
Funny thing is the second ramp is signed for WB while EB gets signed on the previous ramp wit FL 113.
The direction-specific signage is due to WB Merrill Road not being accessible from the SB FL 113 ramp. They designed it in such a way that I-295 NB can make left or right turns off the connecting loop ramp but FL 113 SB can only turn right: https://goo.gl/maps/pxKJYMfrAW5PU3LW9
Quote from: dantheman on July 02, 2023, 04:09:21 PM
Quote from: roadman65 on July 02, 2023, 03:03:13 PM
https://www.google.com/maps/@30.3552199,-81.5548173,16.13z?entry=ttu
Merril Road EB has two exits from I-295 SB. One from the previous exit via FL 113 and the second (actual) ramp to Merrill Road that has a signalized intersection to allow left turns.
https://goo.gl/maps/7nUrdWjvw1nvhnLC8
Funny thing is the second ramp is signed for WB while EB gets signed on the previous ramp wit FL 113.
Bonus points for this one, because if the USGS topos on Acme Mapper can be trusted, this interchange had the same redundancy in its previous design, before FL 113 was turned into a freeway. The SPUI that's now at FL 113 and Merrill Road was a four-way intersection, but the Exit 46 ramp (Merrill Road West) from I-295 SB still had a left-turn available to Merrill Road EB.
In both of these configurations, I can't see any reason why the Exit 46-to-Merrill EB left turn is needed. Why not make the end of that ramp right-turn-only, potentially allowing Merrill Road WB to be free-flowing through that intersection rather than needing a stoplight for the left turn out of the exit ramp? Unlike some examples in this thread, there is not even a single business or driveway between the two ramps, so there is not a single thing that can be accessed uniquely from a left turn from the Exit 46 ramp.
Posted my above comment before I read yours, good points. The best part is they just replaced the traffic light off Exit 46 with a mast arm between 2021 - 2022 per GSV so they likely intend to keep this redundancy for a while.
Quote from: Thing 342 on July 02, 2023, 03:29:12 PM
I-295 SB to I-64 EB has two ramps: a loop ramp from the original cloverleaf interchange plus a flyover that was added in a later project. I'm not really sure why they decided to keep the loop ramp open after the flyover opened.
Redundancy, I suppose, if any accident blocks the flyover ramp, traffic can simply be diverted to the original loop ramp.
I think I have mentioned this one before, but it is a Bay Area example that I've known about for years:
At Santa Teresa Boulevard, Route 85 south has a ramp that allows you to make a left and go to Route 87 north.
https://www.google.com/maps/@37.2549406,-121.8593391,3a,75y,96.88h,91.2t/data=!3m7!1e1!3m5!1sLB1GpxH2RTWQW0DEGXGB3Q!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DLB1GpxH2RTWQW0DEGXGB3Q%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D29.970085%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192?entry=ttu
...Route 85 already has a flyover ramp just before it to reach northbound 87.
The one extra site that this diamond interchange left turn offers any access to is a light rail station (Ohlone/Chynoweth)
^ And that light rail station is likely the reason the left turn lane on the ramp still exists.
Also in Florida the EB Beachline (aka FL 528) has two exits for I-95 NB. One exit at FL 407 (Exit 37) and again Exit 42 B. Originally there was only one as Exit 42 was a parclo with missing movements and had no EB to NB with FL 407 acting as the connection, but later made it into a full Cloverleaf despite the EB to NB ramp was redundant.
However now that the exit on I-95 to Port St. John Parkway was opened it makes sense to have the direct ramp, but before it was just FDOT burning federal funds offered to the when they added two other missing movements it was decided to go the hundred yards and complete it all according to a phone call with a PE at FDOT.
Quote from: JustDrive on July 02, 2023, 02:02:17 PM
SB 405 at the Century/Imperial exits. The east-west designations are for show, as you can access either road in any direction from any ramp.
NB 15 and 215 both access Murrieta Hot Springs Road with complete freedom of movement.
Correct. SB 405 exits place you onto La Cienega. You can reach either direction of Century or Imperial from LC, but the signs lead you to where you do not need to make a left from LC to Century (or Imperial). [That's better for throughput to use right turns over left turns.]
The El Segundo exits used to be that way too, prior to the I-105 construction.
The onramp to US 101 south from Lankershim in Universal City doesn't even hide it anymore:
https://www.google.com/maps/@34.1389449,-118.3621476,3a,39.3y,230.95h,89.89t/data=!3m7!1e1!3m5!1swPW0Ggt7zJy0YQxA_Ts-tA!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DwPW0Ggt7zJy0YQxA_Ts-tA%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D257.35425%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192?entry=ttu
Basically, you drive to Ventura/Cauhenga Bl W and if you make a right turn there is an onramp about a block away and if you make a left turn there is an onramp a block away. Which one is better? It's totally up to you.
The infamous extra-toll exit to I-295 from I-95 just south of Portland, Maine, seems redundant with the next exit to the north, the trumpet:
(https://i.imgur.com/dp3Eaqf.png)
Or at least, it used to be. That northern trumpet exit looks like it's currently under construction to be turned into a diamond.
^ Correct. The diamond is now open, though construction will not wrap up for another month or two.
i suspect that many of these cases involve interchanges that have been upgraded in some way.
Two possibilities I can think of are -- older interstates that were built in sections where there are redundant ramps at what used to be a termination point -- the second ramp was built to eliminate weaving or make the movement easier. I wonder if that was the case for US 29 NB at I-70 (if I-70 ended here at some point in the '60s or early '70s). Or maybe US 29 itself since I'm not sure if the part from I-70 north to MD 99 was built at the same time as the part from US 40 to I-70.
Or -- the intersecting highway itself was majorly upgraded and the existing ramp wasn't good enough anymore. Thinking here of Delaware 7 interchange with I-95 which later became Delaware 1. The old Delaware 7 ramp (which also had a ramp coming into it from Christiana Mall) to I-95 NB wouldn't work for Delaware 1, but was still needed anyway.
A third example I can think of is also an interchange upgrade -- I-370 EB (Maryland) at Shady Grove Rd where there are now two ways to get to Shady Grove Road. One is via the former 370 which is the road that goes to the Shady Grove Metro Station. The other EB ramp was built when MD 200 was built to connect to I-370 (I think the original EB ramp mentioned above was inaccessible (or at least majorly compromised) for a while while they built that new interchange). WB on MD 200 there is only one ramp to get to Shady Grove Road, and that way did not exist before MD 200 was built.
I-70/US-29 was mostly built at one time. If you're not familiar with historicaerials.com, you could probably waste the rest of your day doing "research" . I-370/Shady Grove/MD-200 design changed significantly from the first proposal; the 2 lane loop ramp movement was originally designed as a flyover ramp. As you note there's no duplication of ramps coming from the east, and it seemed to me they just added asphalt on the fly to spread out the traffic onto Shady Grove.
Exits 2B and 2C on I-80 in SF both serve Fremont Street.
I believe this may have to do with removing the Embarcadero Freeway and its interchange with I-80, but still only need one ramp for Fremont Street.