What's the biggest interchange in your state? Is it the best designed?

[SkyPesos]

How are we defining "biggest" interchange?

There's a lot of different ways I can think of, from the one that covers the most land area, to the one with the most road miles, to the one with the highest overall traffic volumes.

It seems like either way can work with what is in the thread already. Like for Ohio, I-70/77 is largest for land area, but I chose one of the busiest by traffic volumes.

[OCGuy81]

How are we defining "biggest" interchange?

There's a lot of different ways I can think of, from the one that covers the most land area, to the one with the most road miles, to the one with the highest overall traffic volumes.

It seems like either way can work with what is in the thread already. Like for Ohio, I-70/77 is largest for land area, but I chose one of the busiest by traffic volumes.

I realize it's kind of a tough definition. Let's go with traffic volume.

[sparker]

The East Los Angeles Interchange, both in volume and sheer size.

Looking at it and the San Bernardino Split just north of there, part of me wonders if the simplest thing would have been to have the Golden State Freeway end right at the San Bernardino Split, and have a simpler interchange for the Pomona/Santa Monica with the Santa Ana instead.  A rail yard north of the Split (and west of I-5/Golden State Freeway) is what possibly precluded this.

In many ways the eventual East Los Angeles configuration + the current route designation choices in the area were adaptive towards existing roads (Santa Ana Freeway, San Bernardino Freeway) rather than the most logical, particularly I-10's jog from the Santa Monica to the Golden State and then San Bernardino Freeways.

Quite correct as to the former SP railyard east of the L.A. River and north of the "San Bernardino Split", which was SP's major regional TOFC (trailers-on-flat-cars, or "piggyback") facility until the mid-'70's, a decade and a half after I-5 was built through Lincoln Heights and Boyle Heights.  Bridging that yard and reconstructing the "split" would have required expanding both the Santa Ana and San Bernardino freeways as part of any project; the latter happened in the late '70's and early '80's while the "split" and the approaches to it haven't been significantly altered since the early '60's, except for the removal of the old single-lane flyover from the WB I-10 spur to SB US 101.  But also the DOH had their "master plan" for an Interstate arc around downtown L.A. consisting of the Golden State/I-5 freeway on the east and the Santa Monica/I-10 freeway on the south, all looping around downtown.  They reasoned that a separate through set of Interstate facilities, not superimposed on the existing "spoke" system emanating from the 4-Level Interchange located downtown, would be optimal to parse out through traffic from that with an origin or destination downtown, which was anticipated to continue using the older/extant freeway facilities.  Of course, the "arc" would be close enough to the city core to also be a partial server (particularly I-10 between current I-110 and the ELA interchange), but the principal aim was to divert, as much as possible, through and interregional traffic from that of downtown.  The basic layout of the "arc" was set in stone when it was decided to extend I-10 west to Santa Monica, with a short segment of the arc hosting both the N-S I-5 and the E-W I-10 through routes. 

All that being said, while the ELA interchange likely occupies more acreage than any other in or near central L.A., it would be interesting to compare its total lane-miles with the I-105/I-110 interchange in South Central; with the duplicative ramps for the HOV lanes along with the general-traffic "stack", and the long approaches to the flyovers, it may come pretty close in terms of those sheer lane-miles.   

In respect to "design", it could be safely said that the ELA interchange wasn't really "designed" as much as fit as well as possible into the topology of the immediate area, including the bluffs on the east side of the L.A. River.  As far as actual architecture goes, the aforementioned I-105/110 interchange is something of a "work of art" (except for that one straggler NB 110>WB 105 loop); fit into the neighborhood (and that during the controversy over displacement stemming from I-105 development) without massive additional loss of local housing.  Upshot -- while 105/110 looks like a well-designed stack, ELA has always reminded me of an overturned bowl of spaghetti.   

It'll be interesting to see how the in-process I-80/680/CA 12 interchange near Cordelia compares to the L.A. examples. 

[Tom958]

I-85/I-285/GA  14 Conn/GA 279 near Hartfield Airport is Georgia's biggest interchange, and the most impressive as far as its layout. However, the short weave on westbound 285 between GA 139 and the offramps to I-85 and the GA 14C-GA 279 CD road is getting to be a serious problem that'll be difficult to fix.

[ahj2000]

Here in VA the Springfield complex is a mess, but it works decently. It takes 95/495/395, both regular lanes as well as express lanes, plus a connection to 644/Franconia Rd, in all kinds of ways. It's a weird intersection. Some of it feels weird. At times, it seems you do way more road miles than necessary, especially when using the Express.

[ran4sh]

I-85/I-285/GA  14 Conn/GA 279 near Hartfield Airport is Georgia's biggest interchange, and the most impressive as far as its layout. However, the short weave on westbound 285 between GA 139 and the offramps to I-85 and the GA 14C-GA 279 CD road is getting to be a serious problem that'll be difficult to fix.

That onramp from 139 to I-285 could just be closed and traffic could be directed to enter via the I-85 interchange nearby

[Tom958]

That onramp from 139 to I-285 could just be closed and traffic could be directed to enter via the I-85 interchange nearby

Yeah, but that would suck.   

[ztonyg]

Arizona's is I-10 / AZ 51 / Loop 202 aka the "mini stack" . It flows okay except for the fact that traffic going straight (unless HOV) has to exit. Lots of delays occur on the Loop 202W to I-10W segment as well as AZ 51S toI-10 E where large volumes of traffic lose lanes in the primary directions.

The best designed interchange is the I-10 / I-17 "stack"  interchange which is overbuilt in some movements but allows traffic to move through it fairly efficiently..

[mgk920]

There are 2 big interchanges by Milwaukee -- Marquette (I-43/94/794) and Zoo (I-41/94/894, US 45).  The Marquette was reconstructed 10 years ago and the Zoo is in its reconstruction, s they are good to ride on.

The Badger Interchange (I-39/90/94/WI 30) in Madison likely covers much more land area than either.

For best designed, I'd have to go with the Zoo Interchange.

Mike

[Occidental Tourist]

Best designed interchange in California would have to be the the 5/14/210 interchange in Sylmar.  It reconfigured and incorporated the existing highway into the new design in a beneficial way as well as addressed the grade issues.

[thspfc]

There are 2 big interchanges by Milwaukee -- Marquette (I-43/94/794) and Zoo (I-41/94/894, US 45).  The Marquette was reconstructed 10 years ago and the Zoo is in its reconstruction, s they are good to ride on.

The Badger Interchange (I-39/90/94/WI 30) in Madison likely covers much more land area than either.

For best designed, I'd have to go with the Zoo Interchange.

Mike

The Badger is a 1970s mess of left exits. WisDOT is lucky that it's in a fairly rural area (so space wasn't a concern) and doesn't serve as much traffic as some other interchanges in its vicinity. But I'm not in the camp that wants it torn down and rebuilt. Spend that $$$ on the Beltline, please.

[1995hoo]

....

1995hoo, any thoughts on what the biggest interchange might be across the Potomac in your state?   

....

Only just now looking at this thread. I think it may be the diamond interchange of VA-79 and I-66 in Linden.

Here in VA the Springfield complex is a mess, but it works decently. It takes 95/495/395, both regular lanes as well as express lanes, plus a connection to 644/Franconia Rd, in all kinds of ways. It's a weird intersection. Some of it feels weird. At times, it seems you do way more road miles than necessary, especially when using the Express.

That interchange is obviously the answer for Virginia. I wouldn't say it's a "mess." Complicated, yes, no question. Unforgiving to someone who makes a mistake, definitely. But a "mess," no, because I'd say it was a complete mess 25 years ago before it was rebuilt into what it is now. The interchange is designed to eliminate big problems with weaving and merging that were inherent in the old design. It segregates local traffic heading to Springfield from long-distance traffic passing through the area, and it does an excellent job of that and it has eliminated some very long backups that occurred on a daily basis (for example, during the afternoon rush hour it used to be that you could forget about getting onto the Beltway's Inner Loop from Van Dorn Street because the backup caused by the weave area on I-95 in Springfield extended more than three miles (thus, past Van Dorn). That's no longer a problem.

If you're not familiar with it, you do have to read and obey all the BGSs telling you which lane to use, and that can cause problems because so many people seem to be used to the idea that it's not a big deal to be in the wrong lane.

[wanderer2575]

(1) the I-96/I-275/I-696/M-5 interchange. This interchange was more ad hock over the years.

Pretty good design considering it was bolted onto over the years.  A five-way interchange with direct connections to all other routes within the interchange.  Only glaring omission is a C/D lane for the two loop ramps on the ramp from wb I-696 to sb I-275.

(2) The I-696/M-10/US-24 interchange.

This interchange flat-out sucks in design.  Tight, low-speed left-hand entrances to M-10, and from sb US-24 to wb I-696 because of an inexplicable curve north on I-696.  Pre-COVID, the loop ramp from sbd M-10 to nbd US-24 backed up considerably during morning rush hours, affecting the ramp from ebd I-696 to sbd M-10.  MDOT recently corrected a similar situation of the latter at I-96/I-196/M-37 in Grand Rapids with a braided ramp, and I wish to blazes they would do the same here.
https://goo.gl/maps/nXrr3GYgZMo8J5hGA

[Mapmikey]

I second the 1995hoo post above - the Springfield Interchange is WAY better than it was when I started using it daily in 1998.

The 95 NB to I-495 WB ramp used to be a tight clover where a lane ended in the middle of the loop!

Although construction of the interchange contributed to this, it was actually faster to use Braddock/Backlick in the afternoon rush hour than 495 EB to 95 SB.  Oddly, during another phase it was faster to use 495 EB/395 NB to Edsall then loop around to 395 SB.

It is definitely true that if you do not end up on the ramp you need to, it is not simple to get back to where you were trying to get to.  But I assume that of all huge urban interchanges nationwide.  This is one reason when I know I'm going somewhere large I am not familiar with, I street view the complicated interchanges so that I know in advance which side of the freeway I need to be on to navigate through them so I don't become a hazard.

[mgk920]

There are 2 big interchanges by Milwaukee -- Marquette (I-43/94/794) and Zoo (I-41/94/894, US 45).  The Marquette was reconstructed 10 years ago and the Zoo is in its reconstruction, s they are good to ride on.

The Badger Interchange (I-39/90/94/WI 30) in Madison likely covers much more land area than either.

For best designed, I'd have to go with the Zoo Interchange.

Mike

The Badger is a 1970s mess of left exits. WisDOT is lucky that it's in a fairly rural area (so space wasn't a concern) and doesn't serve as much traffic as some other interchanges in its vicinity. But I'm not in the camp that wants it torn down and rebuilt. Spend that $$$ on the Beltline, please.

A few more in Wisconsin where I like their designs are the I-39/US 51/WI 29 Rothschild Interchange, the rebuilt I-41/I-43/US 41/141 Howard Interchange, the combined I-41/WI 32 Shawano Interchange/WI 29 Shawano Ave interchange in the Green Bay area, the I-90/94 Tomah Interchange and the currently under construction I-39/90/I-43/WI 81 Beloit Interchange.  Most of the others I am fairly ambivalent towards, although my 'Hall of Shame' includes the I-39/90/94/WI 78 Cascade interchange (overly complicated left exit and entrance and local access disconnect situations), the I-94/US 53 Altoona Interchange (decades obsolete cloverleaf and local disconnects) and the US 41/141 Abrams Interchange (badly laid out southbound lane drop merges).

Mike

[skluth]

Here in VA the Springfield complex is a mess, but it works decently. It takes 95/495/395, both regular lanes as well as express lanes, plus a connection to 644/Franconia Rd, in all kinds of ways. It's a weird intersection. Some of it feels weird. At times, it seems you do way more road miles than necessary, especially when using the Express.

That interchange is obviously the answer for Virginia. I wouldn't say it's a "mess." Complicated, yes, no question. Unforgiving to someone who makes a mistake, definitely. But a "mess," no, because I'd say it was a complete mess 25 years ago before it was rebuilt into what it is now. The interchange is designed to eliminate big problems with weaving and merging that were inherent in the old design. It segregates local traffic heading to Springfield from long-distance traffic passing through the area, and it does an excellent job of that and it has eliminated some very long backups that occurred on a daily basis (for example, during the afternoon rush hour it used to be that you could forget about getting onto the Beltway's Inner Loop from Van Dorn Street because the backup caused by the weave area on I-95 in Springfield extended more than three miles (thus, past Van Dorn). That's no longer a problem.

If you're not familiar with it, you do have to read and obey all the BGSs telling you which lane to use, and that can cause problems because so many people seem to be used to the idea that it's not a big deal to be in the wrong lane.

You definitely have to read the BGSs there. Not long after the redesigned Springfield Mixing Bowl finished, some friends and I drove from Norfolk to DC Six Flags in two cars. The other car's driver was leading and I was following. My friend kept to his GPS because he was so enamored with his new toy (it was 2007). I was following the signs and tried signaling to get him to switch lanes but he didn't pay attention. So we got stuck on I-395 and he then exited at Edsall rather than just continuing through DC on I-395, etc because of the same stupid GPS. I tried to convince him to let me lead, but he wanted to use his toy. (He had gotten our Six Flags tix free through a promo, so that made him in charge in everyone else's eyes.) We did get there eventually, but I learned that day that GPS is not the miracle advertised.

[thspfc]

There are 2 big interchanges by Milwaukee -- Marquette (I-43/94/794) and Zoo (I-41/94/894, US 45).  The Marquette was reconstructed 10 years ago and the Zoo is in its reconstruction, s they are good to ride on.

The Badger Interchange (I-39/90/94/WI 30) in Madison likely covers much more land area than either.

For best designed, I'd have to go with the Zoo Interchange.

Mike

The Badger is a 1970s mess of left exits. WisDOT is lucky that it's in a fairly rural area (so space wasn't a concern) and doesn't serve as much traffic as some other interchanges in its vicinity. But I'm not in the camp that wants it torn down and rebuilt. Spend that $$$ on the Beltline, please.

A few more in Wisconsin where I like their designs are the I-39/US 51/WI 29 Rothschild Interchange, the rebuilt I-41/I-43/US 41/141 Howard Interchange, the combined I-41/WI 32 Shawano Interchange/WI 29 Shawano Ave interchange in the Green Bay area, the I-90/94 Tomah Interchange and the currently under construction I-39/90/I-43/WI 81 Beloit Interchange.  Most of the others I am fairly ambivalent towards, although my 'Hall of Shame' includes the I-39/90/94/WI 78 Cascade interchange (overly complicated left exit and entrance and local access disconnect situations), the I-94/US 53 Altoona Interchange (decades obsolete cloverleaf and local disconnects) and the US 41/141 Abrams Interchange (badly laid out southbound lane drop merges).

Mike

My "very good" tier is the Marquette, Zoo, Mitchell, northern US-51/WI-29 interchange (the one in Wausau just south of WI-52), I-41/I-43, I-41/Shawano Ave, and I-41/US-45 in Oshkosh.

About the Cascade Interchange - it's unique because there are only four important, high-volume movements (both directions of I-90/94 and both directions of I-39).

My "please fix this" tier is the Stadium Interchange, the Beltline/Park Street interchange, and the I-39/90/94/US-151 cloverleaf. The Stadium Interchange needs a major rebuild, similar to that of the Zoo and Marquette but maybe not quite as large. The Park Street interchange could work as a SPUI. The cloverleaf just needs two flyovers for the US-151 to I-39/90/94 movements that are currently loops.

[ahj2000]

Here in VA the Springfield complex is a mess, but it works decently. It takes 95/495/395, both regular lanes as well as express lanes, plus a connection to 644/Franconia Rd, in all kinds of ways. It's a weird intersection. Some of it feels weird. At times, it seems you do way more road miles than necessary, especially when using the Express.

That interchange is obviously the answer for Virginia. I wouldn't say it's a "mess." Complicated, yes, no question. Unforgiving to someone who makes a mistake, definitely. But a "mess," no, because I'd say it was a complete mess 25 years ago before it was rebuilt into what it is now. The interchange is designed to eliminate big problems with weaving and merging that were inherent in the old design. It segregates local traffic heading to Springfield from long-distance traffic passing through the area, and it does an excellent job of that and it has eliminated some very long backups that occurred on a daily basis (for example, during the afternoon rush hour it used to be that you could forget about getting onto the Beltway's Inner Loop from Van Dorn Street because the backup caused by the weave area on I-95 in Springfield extended more than three miles (thus, past Van Dorn). That's no longer a problem.

If you're not familiar with it, you do have to read and obey all the BGSs telling you which lane to use, and that can cause problems because so many people seem to be used to the idea that it's not a big deal to be in the wrong lane.

You definitely have to read the BGSs there. Not long after the redesigned Springfield Mixing Bowl finished, some friends and I drove from Norfolk to DC Six Flags in two cars. The other car's driver was leading and I was following. My friend kept to his GPS because he was so enamored with his new toy (it was 2007). I was following the signs and tried signaling to get him to switch lanes but he didn't pay attention. So we got stuck on I-395 and he then exited at Edsall rather than just continuing through DC on I-395, etc because of the same stupid GPS. I tried to convince him to let me lead, but he wanted to use his toy. (He had gotten our Six Flags tix free through a promo, so that made him in charge in everyone else's eyes.) We did get there eventually, but I learned that day that GPS is not the miracle advertised.

My experiences dealing with other people is the opposite lol. I get a lot of "I can handle this I know a shortcut"  from friends who haven't lived in Nova and then we're on a toll lane to Tysons when we were trying to get to Reagan.

[zachary_amaryllis]

Largest here is obviously the I-25/I-70 interchange (the Mousetrap).  It's fine, but EB 70 -> SB I-25 always clogs up pretty well on the weekends with people coming back from the mountains.

Chris

With the EB 70 to SB 25 movement, is the US 6 freeway also used as an alternative to that movement? I would be surprised if everyone relied on that one ramp movement, but not a lot of people use US 6 to get from EB 70 to SB 25.

I always take US6 myself, but I'm sure there is a good segment of the populace that isn't using Google Maps that just know that I-70 and I-25 connect and they need to get onto I-25 south.  (The US6 WB->I-25 SB traffic also sucks on the weekends.)

I've always been amazed by the amount of people who don't know what "shape" the highways take in their city.  I'm sure my wife has no idea why we take US6 west when we're going to the mountains instead of I-70.

Chris

coming back from the mountains one day, i was trying to go from 76 eb to 25 nb. rest of the highway was fine, but spent about 45 minutes going what... half a mile? to merge onto 25. it might not be the 'biggest' interchange (mousetrap wins imho) but the 76/36/25/270 thing just seems like a hot mess to me.

[tq-07fan]

Maybe the north split in indiana? (65/70) it's being rebuilt this year though.

I think it's one of the I-70/I-465 interchanges.

The eastside one perhaps. They're both about the same size. Actually the current construction plans for the North Split might make it a tad smaller. One of the ideas of its redesign is to make it a little more simpler and efficient. It's large size was partially due to uneeded ramps that were never utilized. I would also wager that the upcoming redesign of the northeast side I-465/I-69 interchange might be among the biggest when completed.

One further note, I wonder how the I-65/Borman Expressway (80/94) interchange is size wise?

Simply going off Google Maps I-65/I-90/I-94/US 12/US 20 looks bigger but you should include 15th Street and US 12-US 20. The ramps that go direct from I-65 to the Indiana Toll Road were added sometime after the 1990's, before that it was a small Breezewood. You had to use US 20 to go under the Toll Road to the stoplight for I-65. I rode through it on Greyhound a half dozen times coming from Chicago and it was confusing, even being a passenger. Using the new toll plazas for each direction off the Toll Road was a really neat solution although the turns are a bit tight.

Jim

[sparker]

Best designed interchange in California would have to be the the 5/14/210 interchange in Sylmar.  It reconfigured and incorporated the existing highway into the new design in a beneficial way as well as addressed the grade issues.

Maybe not the absolute "best", but one that addressed the needs of several routes converging on one "stem" (I-5) and periodically improving them over the years to minimize weaving and lane shifts to get where one needs to go.  The use of the old 1956 4-lane Golden State Freeway as a set of separate truck lanes was something of a stroke of genius considering the NB grade encountered on I-5 starting just below the CA 14 split.  It's just unfortunate that the whole thing sits atop a very active local fault line; parts of the complex have collapsed in each of the major earthquakes that have hit the region since the facility was initially completed in 1970 (Sylmar '71 and Northridge '94).  As long as the freeways use that canyon complex to exit the San Fernando Valley, earthquakes are always going to be a recurring issue; all that can be done is to rebuild using more resistant methods. 

[epzik8]

Maryland: Once fully built out it'll be the northeast I-95/I-695 interchange (currently a 4-level stack, with direct flyovers to/from the I-95 ETL's to be added later), but for the moment it might be a close contest between the aforementioned interchange, I-70/I-695, I-270/I-370, I-95/I-495 College Park, I-95/I-495/I-595/US 50, & I-95/I-495/I-295/Nat'l Harbor.  If I-270/I-495 was one interchange instead of 3 partial interchanges spread out from each other, it would probably be in the running too.  Also worth noting is the 3 closely-spaced interchanges in Frederick where I-70, I-270, US 15, US 40, & US 340 all meet - none of them are too large on their own, but when viewed as one big interchange system I think it's rather impressive.

All are fairly well designed, with a couple exceptions:

-The ramp from I-495 EB to I-95 NB in College Park has a fairly sharp curve, and the last half-mile on I-495 leading up to the ramp has quite a bit of weaving as everyone tries to squeeze over for the exit.
-The I-70/I-695 stack was well-designed for its intended use had I-70 been completed to I-95, but we all know what happened there and now the ramps leading to/from the west are heavily utilized (none more so than I-70 EB to I-695 NB) while to/from the east is underutilized.
-I-70 WB thru the Frederick interchanges has an unusual lane configuration that likely contributes to the recurring congestion there - enters with 3 lanes + an aux lane from exit 54; this aux lane + the right 2 lanes gradually depart at exits 53 & 52 while 2 lanes add on the left from I-270, the left of which ends.  Which leaves 70 with 2 lanes leaving Frederick.  Got all that?

1995hoo, any thoughts on what the biggest interchange might be across the Potomac in your state?   

There are 2 big interchanges by Milwaukee -- Marquette (I-43/94/794) and Zoo (I-41/94/894, US 45).  The Marquette was reconstructed 10 years ago and the Zoo is in its reconstruction, s they are good to ride on.

Have you been down to Milwaukee recently? Zoo has been finished for about 3 years now. It's really nice. One of the best in the country for sure.

Speaking of the Zoo, I saw that this just happened the other day - the driver survived, fortunately.

https://www.youtube.com/watch?v=VsUw5UZEJ4g

I can't believe how massive the National Harbor interchange is. It and exit 3 for MD 210 are practically one super-interchange.

I-70/I-695 is nicely designed, but underused due to the cancellation of I-70 within Baltimore.

[triplemultiplex]

The Badger Interchange (I-39/90/94/WI 30) in Madison likely covers much more land area than either.

If we're talking land area, that big WB->SB loop ramp in Lake Hallie puts that interchange in the running.

[StogieGuy7]

Here in VA the Springfield complex is a mess, but it works decently. It takes 95/495/395, both regular lanes as well as express lanes, plus a connection to 644/Franconia Rd, in all kinds of ways. It's a weird intersection. Some of it feels weird. At times, it seems you do way more road miles than necessary, especially when using the Express.

That interchange is obviously the answer for Virginia. I wouldn't say it's a "mess." Complicated, yes, no question. Unforgiving to someone who makes a mistake, definitely. But a "mess," no, because I'd say it was a complete mess 25 years ago before it was rebuilt into what it is now. The interchange is designed to eliminate big problems with weaving and merging that were inherent in the old design. It segregates local traffic heading to Springfield from long-distance traffic passing through the area, and it does an excellent job of that and it has eliminated some very long backups that occurred on a daily basis (for example, during the afternoon rush hour it used to be that you could forget about getting onto the Beltway's Inner Loop from Van Dorn Street because the backup caused by the weave area on I-95 in Springfield extended more than three miles (thus, past Van Dorn). That's no longer a problem.

If you're not familiar with it, you do have to read and obey all the BGSs telling you which lane to use, and that can cause problems because so many people seem to be used to the idea that it's not a big deal to be in the wrong lane.

You definitely have to read the BGSs there. Not long after the redesigned Springfield Mixing Bowl finished, some friends and I drove from Norfolk to DC Six Flags in two cars. The other car's driver was leading and I was following. My friend kept to his GPS because he was so enamored with his new toy (it was 2007). I was following the signs and tried signaling to get him to switch lanes but he didn't pay attention. So we got stuck on I-395 and he then exited at Edsall rather than just continuing through DC on I-395, etc because of the same stupid GPS. I tried to convince him to let me lead, but he wanted to use his toy. (He had gotten our Six Flags tix free through a promo, so that made him in charge in everyone else's eyes.) We did get there eventually, but I learned that day that GPS is not the miracle advertised.

My experiences dealing with other people is the opposite lol. I get a lot of "I can handle this I know a shortcut"  from friends who haven't lived in Nova and then we're on a toll lane to Tysons when we were trying to get to Reagan.

To this day, visiting NoVa is like my own personal "Back to the Future" sequel.  Dude, I still remember (well) when I-66 ended at the beltway, I-95 continued into DC and was called the Shirley Highway, when the Dulles Access Highway was a free one-way trip from the beltway to the airport (no exits, only entrances) and when I-66 ended somewhere near Manassas. I visit now and it's a wild scene!  But I still don't get lost - just read the signs.

[MCRoads]

I know Colorado was mentioned earlier, however I have to disagree. I think the biggest interchange is definitely the US-36/I-270/I-76/I-25 interchange. It may not have as much traffic as I-70/I-25(I'm betting not by much), but it definitely takes up more space. No question.