When did the cloverleaf fall out of fashion?

[texaskdog]

they are the hos of roadbuilding, cheap and easy

[Scott5114]

Oklahoma was still building them as late as 2010 (US-69/75 with US-70 Durant Bypass).

[sprjus4]

Hampton Roads still holds onto this mess that is I-64 / I-464 / US-17 / VA-168 (Oak Grove Interchange).

https://www.google.com/maps/@36.7609169,-76.2672024,1691m/data=!3m1!1e3!5m1!1e1

The westbound (pointing east) roadway with very little traffic and no congestion has a C/D roadway, while ironically the busiest and most congested weave that is on the eastbound (pointing west) roadway does -not- have any C/D roadway.

This interchange wasn't much of a problem until the VA-168 Oak Grove Connector was constructed in 1999 without any modifications to the then rural interchange for US-17 (then VA-104) Dominion Blvd. Today, US-17 and VA-168 both serve as major outlets to the south, especially with the completion of the US-17 relocation in 2005 and Dominion Blvd freeway in 2017, including growing suburbs in Chesapeake and northeast North Carolina, and fight to merge onto and off I-64 with those one-lane, weaving, 25 mph loops.

Ultimately, flyovers are needed for the I-64 East to VA-168 / US-17 South and VA-168 / US-17 North to I-64 East movements. The C/D configuration and loop ramps between I-464 and I-64 West is adequate for the traffic it handles.

[Ned Weasel]

they are the hos of roadbuilding, cheap and easy

I don't entirely agree. There are several cases where a diamond would have been cheaper and easier, but a cloverleaf was built instead. Some of these were later converted to diamonds. I can think of three examples on I-35 in Kansas alone: the interchanges with US 59 South, Shawnee Mission Parkway, and US 69 North/18th Street Expressway/Roe Avenue.

A cloverleaf is always cheaper and easier than a three-level interchange, but often the expense of building a three-level interchange is not warranted.

[cbeach40]

Good, it's about time we get rid of those weaving nightmares. Don't know why we used them in the first place.

Provides complete free-flow movement with only one structure. The impact of weaving wasn't well understood in the early years of freeways.
Of course, any built in the last 50 years has no excuse.

But there's other issues to consider.  Weaving is just one of many variables when constructing an interchange.

Yeah, and for decades we've had other, better options. Any cloverleaf built since then has been a deliberate choice to build an inferior interchange.

[jeffandnicole]

Good, it's about time we get rid of those weaving nightmares. Don't know why we used them in the first place.

Provides complete free-flow movement with only one structure. The impact of weaving wasn't well understood in the early years of freeways.
Of course, any built in the last 50 years has no excuse.

But there's other issues to consider.  Weaving is just one of many variables when constructing an interchange.

Yeah, and for decades we've had other, better options. Any cloverleaf built since then has been a deliberate choice to build an inferior interchange.

And this is when i question do people ever try to learn from reading the info contained within these forums, or are you too quick to say it's wrong without giving it any thought.

There are options, of which their merits are studied and weighed. A 4 level flyover interchange may be the best solution, but if the community doesn't want something 75 feet in the air, the cost is exhorbranate or there's too many obstructions to build one, they need to look at other options. They review the traffic volumes in the area. They review historical and environmental issues. When they build an interchange,  they don't send an email saying "I'm doing this" and it's done. They takes months or years to figure out the optimal solution.

There was a highway built near me with cloverleaf in the 1980s. They still perform very well.

[Road Hog]

The I-30/I-49 interchange near Texarkana was built in the mid-2000s (and probably designed in the 1990s). It is a 3/4 cloverleaf with C/D lanes and a flyover that was put in to save a house in the NW corner of the interchange.

[webny99]

But there's other issues to consider.  Weaving is just one of many variables when constructing an interchange.

Yeah, and for decades we've had other, better options. Any cloverleaf built since then has been a deliberate choice to build an inferior interchange.

And this is when i question do people ever try to learn from reading the info contained within these forums, or are you too quick to say it's wrong without giving it any thought.

There are options, of which their merits are studied and weighed. A 4 level flyover interchange may be the best solution, but if the community doesn't want something 75 feet in the air, the cost is exhorbranate or there's too many obstructions to build one, they need to look at other options. ...

Yeah, and take this cloverleaf, for example. There's no way you can say that's deliberately inferior when a simple stoplight would have sufficed.

[Flint1979]

MDOT is getting rid of one at the M-46 interchange on I-75. Very outdated design and terrible merging lanes made it dangerous. It's part of a bigger project to widen I-75. I don't like them and hate left lane entrances, exits I don't mind. Like the Lodge and Ford Freeways in Detroit.

[jeffandnicole]

But there's other issues to consider.  Weaving is just one of many variables when constructing an interchange.

Yeah, and for decades we've had other, better options. Any cloverleaf built since then has been a deliberate choice to build an inferior interchange.

And this is when i question do people ever try to learn from reading the info contained within these forums, or are you too quick to say it's wrong without giving it any thought.

There are options, of which their merits are studied and weighed. A 4 level flyover interchange may be the best solution, but if the community doesn't want something 75 feet in the air, the cost is exhorbranate or there's too many obstructions to build one, they need to look at other options. ...

Yeah, and take this cloverleaf, for example. There's no way you can say that's deliberately inferior when a simple stoplight would have sufficed.

That's hardly standard, but you also have a parallel road that mixes into the 2 ramps on the west side of the highway, and there's already traffic lights just to the west and east of the interchange.  Try putting 4 traffic lights into a span of just over 1/4 of a mile, which would result in 2 sets of traffic lights being about 600 feet away from each other. That wouldn't make for great engineering having lights barely 1/10th of a mile apart. 

[webny99]

Yeah, and take this cloverleaf, for example. There's no way you can say that's deliberately inferior when a simple stoplight would have sufficed.

That's hardly standard, but you also have a parallel road that mixes into the 2 ramps on the west side of the highway, and there's already traffic lights just to the west and east of the interchange.  Try putting 4 traffic lights into a span of just over 1/4 of a mile, which would result in 2 sets of traffic lights being about 600 feet away from each other. That wouldn't make for great engineering having lights barely 1/10th of a mile apart.

Right, but that's the whole point. In this case, the cloverleaf wasn't an inferior design. 4 stoplights in 1/4 mile, or even a simple diamond or slip ramp style interchange, would have been inferior. Here's another cloverleaf where a stoplight or maybe even a four-way stop would have sufficed.

[steviep24]

Cheddar explains why the cloverleaf sucks.

https://www.youtube.com/watch?v=7GTZRSPry70&t=314s

[sparker]

At this point, a full cloverleaf/CD arrangement at the now-redesigned I-94/US 31 interchange near Benton Harbor would be a vast improvement over the parclo now projected (see the appropriate thread in Great Lakes for details).  MDOT's continued reductionist attitude toward this project is disappointing, so say the least.

[hobsini2]

They're dangerous and terrible in urban areas. Weaving issues make them dangerous and cut their ability to handle high amounts of traffic. They also take up too much space in urban areas too. Parclos are so much better. Cloverleaf's are hot garbage in urban areas, but they're fine in rural areas. Not sure when we started to realize this but that's largely why they're not popular anymore.

Try telling that to IL! I-80 alone has at least four of them: at I-55 in Joliet is still a cloverleaf, at I-39 near Lasalle, and at I-280 and I-88 east of the Quad Cities.

Don't know about the Quad Cities interchanges. The I-39 interchange works pretty good, but it's in the middle of nowhere. The I-55 interchange needs to be redesigned to at least eliminate the cloverleafs from I-80 to I-55. The I-55 to I-80 cloverleaf ramps don't seem to be as busy, and removing the two cloverleafs would allow longer deceleration lanes along I-55 and longer acceleration lanes along I-80 for the remaining cloverleaf ramps.

It is in the I-80 reconstruction plan that I saw to eliminate the full cloverleaf with I-55. The SB 55 to EB 80 ramp will be more of the fly under kind. The rest of the cloverleaf remains. They did a lengthen of the ramps a few years ago to make the outside movements be faster than the previously posted 30 mph. You can now do those movements at 55 mph easily.

[ChiMilNet]

They're dangerous and terrible in urban areas. Weaving issues make them dangerous and cut their ability to handle high amounts of traffic. They also take up too much space in urban areas too. Parclos are so much better. Cloverleaf's are hot garbage in urban areas, but they're fine in rural areas. Not sure when we started to realize this but that's largely why they're not popular anymore.

Try telling that to IL! I-80 alone has at least four of them: at I-55 in Joliet is still a cloverleaf, at I-39 near Lasalle, and at I-280 and I-88 east of the Quad Cities.

Don't know about the Quad Cities interchanges. The I-39 interchange works pretty good, but it's in the middle of nowhere. The I-55 interchange needs to be redesigned to at least eliminate the cloverleafs from I-80 to I-55. The I-55 to I-80 cloverleaf ramps don't seem to be as busy, and removing the two cloverleafs would allow longer deceleration lanes along I-55 and longer acceleration lanes along I-80 for the remaining cloverleaf ramps.

It is in the I-80 reconstruction plan that I saw to eliminate the full cloverleaf with I-55. The SB 55 to EB 80 ramp will be more of the fly under kind. The rest of the cloverleaf remains. They did a lengthen of the ramps a few years ago to make the outside movements be faster than the previously posted 30 mph. You can now do those movements at 55 mph easily.

And of course, IDOT picks the one movement that isn't nearly as badly needed for the flyover. EB I-80 to NB I-55 should be the obvious one with WB I-80 to SB I-55 being the next. I would say that one should be given third priority. They widened the movements on the interchange about 15 years ago, which also included widening the loops themselves. You can at least go around those without having to slow down to 15-20 mph. That said, I don't understand why they didn't add a flyover at that time, but then again, this is IDOT.

[MCRoads]

Cheddar explains why the cloverleaf sucks.

https://www.youtube.com/watch?v=7GTZRSPry70&t=314s

To normal person, this is pretty informative. As a road geek, it is pretty cringe. They focus on things that don’t really matter, and gloss over stuff that does! They don’t even talk about solutions! The most they have to say is that new interchange locations aren’t having cloverleaf interchanges as an alternative, and how some interchanges need flyovers. No mention of how or why C/D roads work, what they can do to replace the interchange with minimal cost. Every single video about the subject I have seen has talked about how awesome the interchange at CO 43@I-25 is, and how decloverleafing doesn’t need to be expensive. No mention of that here! And to top it all off, most of the interchanges they show aren’t even cloverleafs! If you want to make a video about them, at least do some research.

[silverback1065]

when did MDOT decide to fuck up the us 31 interchange?

[SGwithADD]

A journey of a thousand miles begins with a single step.
On a more serious note, maybe a few of us will be willing to compile it for our own states. There's really not that many when you limit it to freeway-freeway examples only. I'll do New York, excluding the NYC area:

I-90/NY 33
I-81/I-481/NY 481
I-86/NY 201
I-787/NY 7
I-84/NY 17
I-81-86/NY 7: Used to be a full cloverleaf. It's currently under construction and will basically be a diamond with a NB to WB loop when finished.
NY 8-12/NY 49: Currently has 2 flyovers, but it may have been a full cloverleaf in the past. I'm not sure.

I stand to be corrected, but I believe that's an exhaustive list. None of them have C/D roads. NY does not seem to believe in those. NY is also unique in that our most significant 2di's (I-90 and I-87) are mostly tolled, so most interchanges are trumpets, or double-trumpets in the case of freeway-freeway junctions. Of course, this list would quadruple (or more) in length if we included examples involving one or more non-freeways.

I-787/NY 7 has always existed in its current form with the WB/SB flyover.

The I-87/NY 17/NY 7 interchange has already been reconfigured.

Adding four more to the list (three of which are from downstate):
- NY 17 (future I-86) with NY 26.  NY 26 is a short freeway in that span.
- I-87/I-287/Thruway with the Palisades Interstate Pkwy.
- NY 135 and the Southern State Pkwy.
- Northern State Pkwy. and Sunken Meadow State Pkwy.

True that no cloverleafs in NY have C/D lanes now, but the I-81+NY 17/NY 7 interchange used to have C/D lanes before the reconstruction.  If we stretch the definition of what a C/D lane can be to include service roads, then I-87 with the Cross-County could technically count (where Central Park Ave. acts as a service road for I-87).  However, I would no longer consider this to be freeway-to-freeway myself.  Same goes for I-495 (LIE) and the Grand Central Pkwy.

[CtrlAltDel]

Every single video about the subject I have seen has talked about how awesome the interchange at CO 43@I-25 is, and how decloverleafing doesn't need to be expensive.

There is no CO 43. Did you perchance mean US 34?

[hobsini2]

They're dangerous and terrible in urban areas. Weaving issues make them dangerous and cut their ability to handle high amounts of traffic. They also take up too much space in urban areas too. Parclos are so much better. Cloverleaf's are hot garbage in urban areas, but they're fine in rural areas. Not sure when we started to realize this but that's largely why they're not popular anymore.

Try telling that to IL! I-80 alone has at least four of them: at I-55 in Joliet is still a cloverleaf, at I-39 near Lasalle, and at I-280 and I-88 east of the Quad Cities.

Don't know about the Quad Cities interchanges. The I-39 interchange works pretty good, but it's in the middle of nowhere. The I-55 interchange needs to be redesigned to at least eliminate the cloverleafs from I-80 to I-55. The I-55 to I-80 cloverleaf ramps don't seem to be as busy, and removing the two cloverleafs would allow longer deceleration lanes along I-55 and longer acceleration lanes along I-80 for the remaining cloverleaf ramps.

It is in the I-80 reconstruction plan that I saw to eliminate the full cloverleaf with I-55. The SB 55 to EB 80 ramp will be more of the fly under kind. The rest of the cloverleaf remains. They did a lengthen of the ramps a few years ago to make the outside movements be faster than the previously posted 30 mph. You can now do those movements at 55 mph easily.

And of course, IDOT picks the one movement that isn't nearly as badly needed for the flyover. EB I-80 to NB I-55 should be the obvious one with WB I-80 to SB I-55 being the next. I would say that one should be given third priority. They widened the movements on the interchange about 15 years ago, which also included widening the loops themselves. You can at least go around those without having to slow down to 15-20 mph. That said, I don't understand why they didn't add a flyover at that time, but then again, this is IDOT.

Actually, 55 SB to 80 EB is one of the busiest ramps in Joliet. I agree that 80 EB to 55 NB needs to be a fly over and probably will be eventually.

[D-Dey65]

Cheddar explains why the cloverleaf sucks.

https://www.youtube.com/watch?v=7GTZRSPry70&t=314s

To normal person, this is pretty informative. As a road geek, it is pretty cringe. They focus on things that don't really matter, and gloss over stuff that does! They don't even talk about solutions! The most they have to say is that new interchange locations aren't having cloverleaf interchanges as an alternative, and how some interchanges need flyovers. No mention of how or why C/D roads work, what they can do to replace the interchange with minimal cost.

Even C/D roads can be made dysfunctional if they build stuff too close to them though.

[CtrlAltDel]

They're dangerous and terrible in urban areas. Weaving issues make them dangerous and cut their ability to handle high amounts of traffic. They also take up too much space in urban areas too. Parclos are so much better. Cloverleaf's are hot garbage in urban areas, but they're fine in rural areas. Not sure when we started to realize this but that's largely why they're not popular anymore.

Try telling that to IL! I-80 alone has at least four of them: at I-55 in Joliet is still a cloverleaf, at I-39 near Lasalle, and at I-280 and I-88 east of the Quad Cities.

Don't know about the Quad Cities interchanges. The I-39 interchange works pretty good, but it's in the middle of nowhere. The I-55 interchange needs to be redesigned to at least eliminate the cloverleafs from I-80 to I-55. The I-55 to I-80 cloverleaf ramps don't seem to be as busy, and removing the two cloverleafs would allow longer deceleration lanes along I-55 and longer acceleration lanes along I-80 for the remaining cloverleaf ramps.

It is in the I-80 reconstruction plan that I saw to eliminate the full cloverleaf with I-55. The SB 55 to EB 80 ramp will be more of the fly under kind. The rest of the cloverleaf remains. They did a lengthen of the ramps a few years ago to make the outside movements be faster than the previously posted 30 mph. You can now do those movements at 55 mph easily.

And of course, IDOT picks the one movement that isn't nearly as badly needed for the flyover. EB I-80 to NB I-55 should be the obvious one with WB I-80 to SB I-55 being the next. I would say that one should be given third priority. They widened the movements on the interchange about 15 years ago, which also included widening the loops themselves. You can at least go around those without having to slow down to 15-20 mph. That said, I don't understand why they didn't add a flyover at that time, but then again, this is IDOT.

Actually, 55 SB to 80 EB is one of the busiest ramps in Joliet. I agree that 80 EB to 55 NB needs to be a fly over and probably will be eventually.

Just to facilitate discussion a bit, here is an image with the AADT for each of the 8 ramps at the I-55 / I-80 interchange:

[hobsini2]

Thx CAD. That's certainly then feeling I get from driving it regularly.

[ChiMilNet]

Interesting. I didn't realize it was that high. I guess it is pretty well justified then.

[GaryV]

Interesting that all the loop ramps have lower numbers than their opposite-direction corresponding non-loop ramp.  For any given intersection you'd expect about the same number of vehicles coming and going.  It looks like maybe some people avoid the loops.