In the early days of the Interstate System, cloverleaves were almost everywhere. Now they're becoming rarer and rarer. When did we as a road building society reach the point where we said "You know, these things are pretty damn dangerous. We should probably look into studying other types of interchanges."?
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.
Quote from: silverback1065 on June 07, 2020, 09:46:24 PM
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.
In my part of MA, we use the Parclo quite liberally. We do have one full cloverleaf: Exit 9 on the Mid-Cape. From there the MC is a Super 2 known as Suicide Alley. The next three exits are parclos. Off Cape, the nearest clover is on 195 and is the exit to Marion.
My definition is offsetting loops so their movements don't interfere. Think exit 33 on I-465 in Indianapolis.
There are only a handful of cloverleafs in CT and they're all substandard.
Seems obvious they fell out of favor as traffic volumes and thru traffic speeds increased, making weave/merge movements with thru traffic more hazardous and disruptive. Note that cloverleafs are still generally acceptable with collector/distributor lanes, which have no effect on the volume of weave/merge movements but eliminate the thru traffic.
Quote from: silverback1065 on June 07, 2020, 09:46:24 PM
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.
This one seems to work just fine despite the oddly shaped ramps and low-speed geometry, but these highways are signed at 45 MPH, not 55 or greater: https://goo.gl/maps/6pCMX8BSFabdU3h1A
If there's one reason I'd change it, it would be to improve pedestrian access, because that's hard to do right now without the expense of building pedestrian overpasses.
In general, I think cloverleaves on higher-speed roads are fine if you add C-D lanes,
except when one of the left-turning movements has a significantly high volume and is unduly burdened by going through the weaving/loop path. But if you want one of the roads to have good pedestrian/bicycle access, I'd go with a diamond, SPUI, diverging diamond, roundabout diamond, folded diamond, or maybe a parclo depending on how you handle the free-flowing geometry.
Quote from: silverback1065 on June 07, 2020, 09:46:24 PM
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.
Quote from: silverback1065 on June 07, 2020, 09:46:24 PM
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.
FTFY :-D
Not nitpicking, just saying I wouldn't even qualify it with urban vs rural. Weaving is *the* problem in any setting, just the busier the highway the more amplified the problem is. A very large portion on my transportation engineering course back in college was dedicated just to dealing with it. Causes breakdowns in throughput and dramatically increases collision rates.
There's a lot of variation as to when it fell out of favour. Here in Ontario we last built one in about 1964. Other jurisdictions have built them into the 21st century. But yes, their day is definitely done.
Hello from merry old Ireland, where we've got lucky clovers for anyone and everyone! Oprah says you get a cloverleaf, and YOU get a cloverleaf, and even YOU TOO can have a cloverleaf!
Maryland has done quite a bit of de-cloverleafing over the years to eliminate the weaving problem, in particular along the beltways. Here's some examples of interchanges that are now parclos:
I-495: exit 3 (done as part of the WWB replacement project), exit 7 (in this case, replaced a cloverleaf with a turbine flyover ramp), exit 15, exit 17, exit 19 (in this case, upgraded to a turbine interchange with 1 remaining cloverleaf), exit 20 (which also helps explain this phantom gantry (https://www.google.com/maps/@38.9585616,-76.8658404,3a,75y,169.86h,92.3t/data=!3m6!1e1!3m4!1slK3qYCqWhZwnrVX3hHzLQA!2e0!7i16384!8i8192?hl=en)), exit 25, exit 29, exit 31 (the remaining 3/4-cloverleaf still leaves a lot to be desired), exit 33
I-695: exit 15, exit 18, exit 26, exit 27, exit 31
There's also 2 unusual cases at I-70 exit 87 (https://www.google.com/maps/@39.2968182,-76.823252,895m/data=!3m1!1e3?hl=en) & I-83 exit 20 (https://www.google.com/maps/@39.4947974,-76.6675497,446m/data=!3m1!1e3?hl=en): For the US 29 NB->I-70 WB and Shawan Rd WB->I-83 SB movements, traffic can either take the original cloverleaf ramp or use a left-turn across the opposing direction, which then puts them on the ramp coming from that opposite direction. My guess is that these were both done so that traffic can make these movements from either side of the road, and not have to squeeze all the way to the right to take the cloverleaf.
Are other states as big into de-cloverleafing as MD is?
Regarding the creation of the cloverleaf: The 1st cloverleaf was constructed in NJ, well before limited access highways were built.
You know what else was basically a NJ invention - the traffic circle (NJ inventing it is an exaggeration, but they certainly went all in with them).
And another often used function in NJ: The jughandle.
If you notice the similarities above: NJ wanted to keep traffic flowing, with minimal causes for stoppage. But, as was noted above, these traffic control functions also take up a lot of real estate. Many interchanges either don't need to have continuous traffic flow on the cross street, or there's too much traffic on either roadway that would overpower a cloverleaf. Weaving is always an issue, and along with that is the natural substandard accel/decal lanes cloverleafs provide within that weaving movement.
Even NJ tended to build cloverleafs where it made more sense. Using South Jersey for an example, while NJDOT had to plow thru NJ 42, I-76 & I-295 into the older existing Philly suburbs, full cloverleaf interchanges aren't found in those older suburbs. Only as you travelled further away from those older suburbs would you start finding cloverleaves, such as where 295 meets 70 & 73. NJ 42 doesn't feature any full cloverleaf interchanges.
Most states don't consider cloverleafs for their interchanges, or they are so far down the list of options they would only get looked at if there's issues with their preferred designs. Nothing wrong with that - while it's good to consider options, there's nothing that requires every available option to be considered.
Because NJ isn't really building highways anymore, there aren't many new cloverleafs in the state. However, it's not for the lack of trying. When they review intersections to be upgraded to grade-separated interchanges, cloverleafs are still considered, and then accepted or rejected based on engineering studies and traffic projections. Jughandles are more likely where you're going to find some sort of cloverleaf being built in the state.
I think the question isn't so much "When did cloverleaves fall out of fashion?" It's more "When did C/D roads become the fashion?"
Quote from: jmacswimmer on June 08, 2020, 12:46:12 PM
Maryland has done quite a bit of de-cloverleafing over the years to eliminate the weaving problem, in particular along the beltways. ...
Are other states as big into de-cloverleafing as MD is?
VDOT is in the process of modifying two of I-395's partial cloverleafs, the ones at Duke Street and Edsall Road. Both were already more like three-quarter cloverleafs in that the movement from the eastbound arterial to northbound I-395 that would normally be accomplished via a loop ramp in the cloverleaf's southeastern quadrant was replaced with a flyover ramp. Problem was, the southbound side of I-395 suffered from the lack of C/D roads. At Duke Street, VDOT has removed the loop-around exit ramp from southbound I-395 to eastbound Duke Street (southwest quadrant of interchange) and modified the other southbound exit ramp such that you now exit and then either head west on Duke Street or turn left at a new traffic light to head eastbound; they've also created a lengthy new approach road such that traffic entering from Duke Street (at least from eastbound Duke Street) now joins I-395 via the existing Turkeycock ramp serving as a way out of the express lanes. The Edsall Road interchange just south of there has been modified by removing the loop-around ramp from westbound Edsall to southbound I-395 such that instead you turn left at a new light. In both cases, eliminating one of the loop ramps eliminates a weave area in the rightmost thru lane of southbound I-395.
My impression is that very few new cloverleafs were built after the mid 1960s.
Quote from: kkt on June 08, 2020, 02:51:37 PM
My impression is that very few new cloverleafs were built after the mid 1960s.
I can think of a number of examples built since 1980:
- I-35E/MN 77 (albeit with C/D roads in 35E)
- MN 13/MN 77
- I-35/US 14
- US 169/MN 610
- US 24/US 31
- US 45/US 84 (albeit with C/D roads on 84)
- I-55/I-69/I-269 (albeit with C/D roads on 55)
- I-22/I-269/US 78 (albeit with C/D roads)
- Many of the interchanges along VA 288
- Most of I-664 in Suffolk, VA
Some of these were built after 2000.
Quote from: kkt on June 08, 2020, 02:51:37 PM
My impression is that very few new cloverleafs were built after the mid 1960s.
I would add a caveat: very few new
interstate to interstate cloverleafs, especially in urban areas.
Quote from: Henry on June 08, 2020, 10:51:14 AM
Quote from: silverback1065 on June 07, 2020, 09:46:24 PM
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.
Quote from: jeffandnicole on June 08, 2020, 12:54:28 PM
Regarding the creation of the cloverleaf: The 1st cloverleaf was constructed in NJ, well before limited access highways were built.
You know what else was basically a NJ invention - the traffic circle (NJ inventing it is an exaggeration, but they certainly went all in with them).
And another often used function in NJ: The jughandle.
There's also the at-grade cloverleaf intersection, which is basically a hybrid between a cloverleaf and a set of jughandles.
Quote from: kkt on June 08, 2020, 02:51:37 PM
My impression is that very few new cloverleafs were built after the mid 1960s.
Florida used them in bunches for throughout their interstate binge of the 1970s and early-1980s. Lots of fresh right-of-way. Loads of parclos also remain...yay for 25 mph traffic trying to merge in with overzealous right-lane passers!
Good, it's about time we get rid of those weaving nightmares. Don't know why we used them in the first place.
CDOT has done a reasonable job eliminating cloverleafs. One that remains is Exit 2 on I-270 with US 6-85 (https://www.google.com/maps/place/I-270,+Colorado/@39.8001071,-104.9352973,17z/data=!3m1!4b1!4m5!3m4!1s0x876c7a2051334de7:0xf718ca9098fe68f3!8m2!3d39.8001071!4d-104.9331086) in Commerce City. That one is hot garbage-from 6 to 9 in the morning and 2-7 in the afternoon will always see congestion. Too many trucks slowing down to exit to/from the industrial areas.
Quote from: froggie on June 08, 2020, 03:36:56 PM
Quote from: kkt on June 08, 2020, 02:51:37 PM
My impression is that very few new cloverleafs were built after the mid 1960s.
I can think of a number of examples built since 1980:
- I-35E/MN 77 (albeit with C/D roads in 35E)
- MN 13/MN 77
- I-35/US 14
- US 169/MN 610
- US 24/US 31
- US 45/US 84 (albeit with C/D roads on 84)
- I-55/I-69/I-269 (albeit with C/D roads on 55)
- I-22/I-269/US 78 (albeit with C/D roads)
- Many of the interchanges along VA 288
- Most of I-664 in Suffolk, VA
Some of these were built after 2000.
A few in North Carolina in the past couple decades -
- I-95 / I-795 / US-264 (C/D roads on I-95) - around 2006
- US-264 / NC-11 Bypass - 2019
- US-70 / US-17 (only partially in use, stub on north side) - around 2012
- I-95 / I-74 (C/D roads on I-95) - around 2008
- US-1 / US-421 (C/D roads on US-421) - around 2008
- I-85 / I-73 (C/D roads on both) - around 2006
- I-85 / US-421 (C/D roads on both, one flyover) - around 2006
In Chesapeake, VA, the I-64 / VA-168 Business (Battlefield Blvd) interchange was originally a smaller cloverleaf. Around 2008, the entire interchange was reconstructed with a new, wider cloverleaf with new C/D roadways on I-64, and a new overpass.
Quote from: formulanone on June 08, 2020, 08:12:52 PM
Quote from: kkt on June 08, 2020, 02:51:37 PM
My impression is that very few new cloverleafs were built after the mid 1960s.
Florida used them in bunches for throughout their interstate binge of the 1970s and early-1980s. Lots of fresh right-of-way. Loads of parclos also remain...yay for 25 mph traffic trying to merge in with overzealous right-lane passers!
This is why keeping to the right except to pass is important. For some reason, the slower vehicle drivers think they are safer in the middle lanes, which in fact they are causing many of the safety issues on the highway.
Quote from: jeffandnicole on June 09, 2020, 07:59:48 AM
This is why keeping to the right except to pass is important. For some reason, the slower vehicle drivers think they are safer in the middle lanes, which in fact they are causing many of the safety issues on the highway.
Yes, the slowest traffic mostly belongs in the right-most lane.
I think in (mostly urban) places where there's a lot of exits spaced out every mile (or less), it's understandable to not hang out there if you're at least doing the speed limit, if there's several lanes of travel.
Quote from: Amtrakprod on June 08, 2020, 08:31:11 PM
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.
Quote from: webny99 on June 08, 2020, 03:40:54 PM
Quote from: kkt on June 08, 2020, 02:51:37 PM
My impression is that very few new cloverleafs were built after the mid 1960s.
I would add a caveat: very few new interstate to interstate cloverleafs, especially in urban areas.
As a follow-up, I can think of various freeway-to-freeway ones that have been modified due to congestion caused by the weaving problem. The two that most readily come to mind are the Capital Beltway and US-50 (unsigned I-595) in Maryland (only one loop ramp remains there) and the I-77/I-40 interchange in Statesville (three loops remain). I'd have to think harder to come up with other ones; these are just the two that immediately come to mind when I consider the issue.
Quote from: cbeach40 on June 09, 2020, 09:44:20 AM
Quote from: Amtrakprod on June 08, 2020, 08:31:11 PM
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.
There are a few remaining interstate highway cloverleaves left here in Wisconsin, one that I know is being actively studied for elimination (I-43/WI 100/Drown Deer Rd in northern Milwaukee County) and one elimination is under construction (I-39/90/I-43/WI 81 in Beloit). One was rebuilt a few years ago with new C/D lanes on the interstate side (I-39/90/94/US 151/Washington Ave in Madison), one that I know of was built with C/D lanes on the interstate side (I-43/WI 23 in Sheboygan), one just makes be scratch my head, but has C/D lanes (I-94/US 53 in Eau Claire) and one non-interstate freeway to freeway one was built new since 2000 (US 53/WI 29 between Eau Claire and Chippewa Falls). There is also an interstate one with C/D lanes on the non-interstate side (I-43/US 12 in Elkhorn).
Mike
So does anyone have a real answer to the question from the OP? When did agencies start moving cloverleaf interchanges down the list?
Quote from: kphoger on June 09, 2020, 11:50:28 AM
So does anyone have a real answer to the question from the OP? When did agencies start moving cloverleaf interchanges down the list?
1983½ model year
The I-94/I-69 interchange was built as a full cloverleaf, but with C/D ramps. This was about 1967.
Quote from: kphoger on June 09, 2020, 11:50:28 AM
So does anyone have a real answer to the question from the OP? When did agencies start moving cloverleaf interchanges down the list?
It would vary by state DOT, but my rough guess would be "late '70s" based on various facilities I'm familiar with. The full eight-ramp cloverleaf, as used for freeway-freeway connections, was still quite popular through the '60s, spanning most of the original Interstate construction period, and it continued to be rolled out into the mid "˜70s, mostly on freeways that had been designed and were in progress since the previous decade.
I'd be mildly interested in seeing some sort of count of how many freeway-to-freeway cloverleaf interchanges each state has, potentially further broken out into with and without C/D roadways, and a count of how many of each category each state used to have that have since been modified. But I have no idea where to find that information nor the motivation to try to compile it.
My sense is that some states have been more likely than others to build that style of interchange; for example, I-26 in South Carolina readily comes to mind as one that used to have three non-C/D road cloverleafs with other Interstates (I-95, I-20, and I-85; the I-85 one still exists in the same form, but it's now an interchange with I-85 Business due to the road being moved to a new alignment).
Quote from: 1995hoo on June 09, 2020, 02:47:46 PM
I have no idea where to find that information
googlemaps.com?
Quote from: 1995hoo on June 09, 2020, 02:47:46 PM
nor the motivation to try to compile it.
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.
Quote from: webny99 on June 09, 2020, 03:29:52 PM
Quote from: 1995hoo on June 09, 2020, 02:47:46 PM
I have no idea where to find that information
googlemaps.com?
Aside from the obvious practical issue of the massive amount of time that would take, it doesn't help with historical data. For example, the interchange of the Capital Beltway and US-50 that I mentioned earlier would be a good example–Google Maps shows the current configuration and not the old cloverleaf.
Quote from: webny99 on June 09, 2020, 03:29:52 PM
....
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.
The issue noted in boldface definitely occurred to me as an issue that prevails in several places in the Northeast.
Kentucky cloverleafs, full freeway to full freeway:
I-64/I-265 (will be replaced)
I-71/I-265 (will be replaced)
I-65/I-165-Natcher Parkway (has CD lanes on I-65)
I-65/WK Parkway-US 31W-KY 61 (has CD lanes on I-65)
I-165/WK Parkway
Replaced as part of the I-69 construction:
I-24/Purchase Parkway
WK Parkway/Pennyrile Parkway
There are some cloverleafs on various interstates in urban areas, but they are not freeway-to-freeway junctions.
Quote from: formulanone on June 09, 2020, 09:10:41 AM
I think in (mostly urban) places where there's a lot of exits spaced out every mile (or less), it's understandable to not hang out there if you're at least doing the speed limit, if there's several lanes of travel.
In Connecticut, where it is common for freeways to have high traffic volumes, for exits to be spaced less than a mile apart, and for acceleration and deceleration lanes to be too short for the de facto speeds, the middle lane is the lane with the most stable, consistent speeds.
Attempting to keep to the right lane leads to frequent lane changes (if traffic is light enough accommodate the change), or frequent speed changes due to exiting traffic slowing down, and entering traffic merging in at less than the prevailing speeds.
The situation is such that driving schools in the state frequently teach the middle lane as being the "thru lane", with the left lane reserved for passing, and the right lane reserved for extended entry/exit movements or vehicles unable to keep up with highway speeds.
Here's my attempt at Maryland's freeway-to-freeway cloverleafs:
I-70/I-81 (with full CD lanes on both routes)
I-95-495/MD 4 (4's freeway segment currently stops a mile and half to the southeast, but is planned to eventually continue all the way to the beltway)
I-95-495/MD 295
US 50/MD 201/MD 295 (there's a lot of stuff happening here, probably easier to look for yourself (https://www.google.com/maps/@38.9208342,-76.9313174,899m/data=!3m1!1e3?hl=en) than me attempt to explain)
I-95/MD 200 (with full CD lanes on I-95, plus an additional express flyover ramp for the EB-NB movement)
US 29/MD 32 (32 East has a double-line-separated CD lane)
MD 295/MD 32
MD 295/MD 100 (100 East has a double-line-separated CD lane)
I-695/MD 295
Also including some 3/4-cloverleafs:
I-95-495/MD 5
I-70/US 29
I-695/I-83 South
I-95/MD 100
I-195/MD 295
Finally, also worth noting that every interchange on I-95 "between the beltways" is either a full cloverleaf or partial cloverleaf, with the exception of exits 32 & 46.
Quote from: 1995hoo on June 09, 2020, 03:45:40 PM
Quote from: webny99 on June 09, 2020, 03:29:52 PM
Quote from: 1995hoo on June 09, 2020, 02:47:46 PM
I have no idea where to find that information
googlemaps.com?
Aside from the obvious practical issue of the massive amount of time that would take, it doesn't help with historical data. For example, the interchange of the Capital Beltway and US-50 that I mentioned earlier would be a good example–Google Maps shows the current configuration and not the old cloverleaf.
I wasn't really being serious and almost added an emoji to indicate such, but your point about the historical data is a good one. Hadn't thought of that.
Quote from: 1995hoo on June 09, 2020, 03:45:40 PM
Quote from: webny99 on June 09, 2020, 03:29:52 PM
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.
The issue noted in boldface definitely occurred to me as an issue that prevails in several places in the Northeast.
I wasn't thinking of it is an issue
per se, except that it just means we tend to have fewer cloverleaf interchanges. And, in the case of New York, there's so few that the state has never really had a reason to consider improvements, such as C/D roads, that have become commonplace in other states.
Minneapolis & Saint Paul loved them. Here in Austin I know there are a couple (183 & 71 which may disappear in current reconstruction; Mopac & 35th kind of; I'd have to think but there are probably a couple more). generally we have flyovers or you have to exit, take a left, and get on the next highway
Quote from: webny99 on June 09, 2020, 04:24:20 PM
Quote from: 1995hoo on June 09, 2020, 03:45:40 PM
Quote from: webny99 on June 09, 2020, 03:29:52 PM
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.
The issue noted in boldface definitely occurred to me as an issue that prevails in several places in the Northeast.
I wasn't thinking of it is an issue per se, except that it just means we tend to have fewer cloverleaf interchanges. And, in the case of New York, there's so few that the state has never really had a reason to consider improvements, such as C/D roads, that have become commonplace in other states.
I didn't mean to use the word "issue" in the sense of "problematic," but I can see how my comment might have been interpreted that way. I just meant that in the Northeast I think there is a relatively high percentage of toll roads or former toll roads, especially "ticket system" toll roads, that would place a natural limit on the use of cloverleafs that might not be an issue in states with fewer toll roads or higher percentages of free Interstate-grade highways. (Certainly there are toll roads that use the barrier toll system that do have cloverleafs; the Powhite Parkway, VA-76, near Richmond comes to mind, as it has a freeway-to-freeway cloverleaf with VA-288 that has C/D roads only on VA-288, although I suppose that interchange is to the west of the last toll barrier.)
US-131/M-6 was built as a cloverleaf (with C/D roads) in 2004
Quote from: webny99 on June 09, 2020, 03:29:52 PM
Quote from: 1995hoo on June 09, 2020, 02:47:46 PM
I have no idea where to find that information
googlemaps.com?
Quote from: 1995hoo on June 09, 2020, 02:47:46 PM
nor the motivation to try to compile it.
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 (https://www.google.com/maps/@42.1150736,-75.897324,3a,57.7y,218.7h,86.14t/data=!3m6!1e1!3m4!1s9KFyOuLjAm_Zp9fT_rQmyg!2e0!7i16384!8i8192).
Quote from: vdeane on June 09, 2020, 08:46:25 PM
The I-87/NY 17/NY 7 interchange has already been reconfigured (https://www.google.com/maps/@42.1150736,-75.897324,3a,57.7y,218.7h,86.14t/data=!3m6!1e1!3m4!1s9KFyOuLjAm_Zp9fT_rQmyg!2e0!7i16384!8i8192).
OK, I wasn't aware of the current project status. It's been ongoing for so long that I had my doubts that construction had fully wrapped.
Quote from: formulanone on June 08, 2020, 08:12:52 PM
Quote from: kkt on June 08, 2020, 02:51:37 PM
My impression is that very few new cloverleafs were built after the mid 1960s.
Florida used them in bunches for throughout their interstate binge of the 1970s and early-1980s. Lots of fresh right-of-way. Loads of parclos also remain...yay for 25 mph traffic trying to merge in with overzealous right-lane passers!
One of the most recent ones I know about is US 27 and FL 50 in Clermont. The southern portion of it really needs to be fixed though.
Vermont is easy in this regard...we only have three freeway-to-freeway interchanges to begin with. And none of them are traditional cloverleaf interchanges.
Quote from: jmacswimmer on June 09, 2020, 04:23:45 PM
Here's my attempt at Maryland's freeway-to-freeway cloverleafs:
I-70/I-81 (with full CD lanes on both routes)
And it still has short/no merge areas.
Quote from: hbelkins on June 10, 2020, 01:30:03 PM
And it still has short/no merge areas.
Here's one with neither C-D lanes nor auxiliary lanes: https://goo.gl/maps/sRqTJASPN2sRt8XV7
But it has stop signs at the ends of the ramps!
Tennessee has three of these:
I-81 and I-26 (when built in the mid-70's, I-26 was still US 23)
I-24 and TN 155 Briley Pkwy in NW Nashville (I-24 has C/D lanes)
I-40 and I-269/TN 385 in Arlington (I-40 has C/D lanes), which is the newest of the bunch, built in the late 90's.
they are the hos of roadbuilding, cheap and easy
Oklahoma was still building them as late as 2010 (US-69/75 with US-70 Durant Bypass).
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.
Quote from: texaskdog on June 10, 2020, 08:38:27 PM
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.
Quote from: jeffandnicole on June 09, 2020, 10:16:11 AM
Quote from: cbeach40 on June 09, 2020, 09:44:20 AM
Quote from: Amtrakprod on June 08, 2020, 08:31:11 PM
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.
Quote from: cbeach40 on June 12, 2020, 05:13:13 PM
Quote from: jeffandnicole on June 09, 2020, 10:16:11 AM
Quote from: cbeach40 on June 09, 2020, 09:44:20 AM
Quote from: Amtrakprod on June 08, 2020, 08:31:11 PM
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.
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.
Quote from: jeffandnicole on June 12, 2020, 05:37:14 PM
Quote from: cbeach40 on June 12, 2020, 05:13:13 PM
Quote from: jeffandnicole on June 09, 2020, 10:16:11 AM
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 (https://www.google.com/maps/@43.2037584,-77.660569,17z/data=!5m1!1e1), for example. There's no way you can say that's deliberately inferior when a simple stoplight would have sufficed.
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.
Quote from: webny99 on June 12, 2020, 10:49:17 PM
Quote from: jeffandnicole on June 12, 2020, 05:37:14 PM
Quote from: cbeach40 on June 12, 2020, 05:13:13 PM
Quote from: jeffandnicole on June 09, 2020, 10:16:11 AM
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 (https://www.google.com/maps/@43.2037584,-77.660569,17z/data=!5m1!1e1), 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.
Quote from: jeffandnicole on June 13, 2020, 01:39:35 AM
Quote from: webny99 on June 12, 2020, 10:49:17 PM
Yeah, and take this cloverleaf (https://www.google.com/maps/@43.2037584,-77.660569,17z/data=!5m1!1e1), 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 (https://www.google.com/maps/@42.946953,-76.9759879,17z/data=!5m1!1e1) where a stoplight or maybe even a four-way stop would have sufficed.
Cheddar explains why the cloverleaf sucks.
https://www.youtube.com/watch?v=7GTZRSPry70&t=314s
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.
Quote from: skluth on June 08, 2020, 05:08:46 PM
Quote from: Henry on June 08, 2020, 10:51:14 AM
Quote from: silverback1065 on June 07, 2020, 09:46:24 PM
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.
Quote from: hobsini2 on July 18, 2020, 07:55:39 PM
Quote from: skluth on June 08, 2020, 05:08:46 PM
Quote from: Henry on June 08, 2020, 10:51:14 AM
Quote from: silverback1065 on June 07, 2020, 09:46:24 PM
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.
Quote from: steviep24 on July 18, 2020, 05:59:28 PM
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.
when did MDOT decide to fuck up the us 31 interchange?
Quote from: vdeane on June 09, 2020, 08:46:25 PM
Quote from: webny99 on June 09, 2020, 03:29:52 PM
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 (https://www.google.com/maps/@42.1150736,-75.897324,3a,57.7y,218.7h,86.14t/data=!3m6!1e1!3m4!1s9KFyOuLjAm_Zp9fT_rQmyg!2e0!7i16384!8i8192).
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.
Quote from: MCRoads on July 19, 2020, 05:23:46 PM
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?
Quote from: ChiMilNet on July 19, 2020, 01:06:08 PM
Quote from: hobsini2 on July 18, 2020, 07:55:39 PM
Quote from: skluth on June 08, 2020, 05:08:46 PM
Quote from: Henry on June 08, 2020, 10:51:14 AM
Quote from: silverback1065 on June 07, 2020, 09:46:24 PM
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.
Quote from: MCRoads on July 19, 2020, 05:23:46 PM
Quote from: steviep24 on July 18, 2020, 05:59:28 PM
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.
Quote from: hobsini2 on July 20, 2020, 03:34:59 PM
Quote from: ChiMilNet on July 19, 2020, 01:06:08 PM
Quote from: hobsini2 on July 18, 2020, 07:55:39 PM
Quote from: skluth on June 08, 2020, 05:08:46 PM
Quote from: Henry on June 08, 2020, 10:51:14 AM
Quote from: silverback1065 on June 07, 2020, 09:46:24 PM
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:
(https://i.imgur.com/Fujdzxv.png)
Thx CAD. That's certainly then feeling I get from driving it regularly.
Interesting. I didn't realize it was that high. I guess it is pretty well justified then.
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.
Quote from: CtrlAltDel on July 20, 2020, 05:39:12 AM
Quote from: MCRoads on July 19, 2020, 05:23:46 PM
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?
Dang it. Yes, that is indeed what I had in mind. We drive on 25 all the time, but almost never 34, so I guess being close is still pretty good.
Quote from: ChiMilNet on July 20, 2020, 05:28:03 PM
Interesting. I didn't realize it was that high. I guess it is pretty well justified then.
I didn't know that, either. It makes sense, though. IL 59 runs due south, then ends and goes pretty much straight onto I-55. I can see a lot of that traffic taking the loop ramp.
I'm also surprised at just how low the AADT is between the two legs leading away from Chicago. I figured it would be lower, but a lot higher than 15-20% of the traffic of the busiest ramps.
Quote from: GaryV on July 20, 2020, 06:12:07 PM
Interesting that all the loop ramps have lower numbers than their opposite-direction corresponding non-loop ramp.
Only one of the pairs has more than a 10% difference, though.
E→S = 1,800 / N→W = 1,700 (5.6% lower)
N→E = 7,800 / W→S = 6,600 (15.4% lower)
W→N = 8,800 / S→E = 8,500 (3.4% lower)
S→W = 11,000 / E→N = 10,100 (8.2% lower)
Quote from: kphoger on July 21, 2020, 11:03:49 AM
Quote from: GaryV on July 20, 2020, 06:12:07 PM
Interesting that all the loop ramps have lower numbers than their opposite-direction corresponding non-loop ramp.
Only one of the pairs has more than a 10% difference, though.
E→S = 1,800 / N→W = 1,700 (5.6% lower)
N→E = 7,800 / W→S = 6,600 (15.4% lower)
W→N = 8,800 / S→E = 8,500 (3.4% lower)
S→W = 11,000 / E→N = 10,100 (8.2% lower)
Those percentages probably correlate roughly with the percentage of trips for which an alternate route is faster than the loop... but not the non-loop.
Quote from: webny99 on July 21, 2020, 02:12:09 PM
Quote from: kphoger on July 21, 2020, 11:03:49 AM
Quote from: GaryV on July 20, 2020, 06:12:07 PM
Interesting that all the loop ramps have lower numbers than their opposite-direction corresponding non-loop ramp.
Only one of the pairs has more than a 10% difference, though.
E→S = 1,800 / N→W = 1,700 (5.6% lower)
N→E = 7,800 / W→S = 6,600 (15.4% lower)
W→N = 8,800 / S→E = 8,500 (3.4% lower)
S→W = 11,000 / E→N = 10,100 (8.2% lower)
Those percentages probably correlate roughly with the percentage of trips for which an alternate route is faster than the loop... but not the non-loop.
Doubt it.
Why else would the volumes on the loop be lower? I thought I was just stating the obvious... probably true for every loop, not just these ones.
Quote from: kphoger on July 21, 2020, 02:17:48 PM
Quote from: webny99 on July 21, 2020, 02:12:09 PM
Quote from: kphoger on July 21, 2020, 11:03:49 AM
Quote from: GaryV on July 20, 2020, 06:12:07 PM
Interesting that all the loop ramps have lower numbers than their opposite-direction corresponding non-loop ramp.
Only one of the pairs has more than a 10% difference, though.
E→S = 1,800 / N→W = 1,700 (5.6% lower)
N→E = 7,800 / W→S = 6,600 (15.4% lower)
W→N = 8,800 / S→E = 8,500 (3.4% lower)
S→W = 11,000 / E→N = 10,100 (8.2% lower)
Those percentages probably correlate roughly with the percentage of trips for which an alternate route is faster than the loop... but not the non-loop.
Doubt it.
Quote from: webny99 on July 21, 2020, 02:20:32 PM
Why else would the volumes on the loop be lower? I thought I was just stating the obvious... probably true for every loop, not just these ones.
I mean, show me such a trip–especially the pair with a 15% difference.
Quote from: kphoger on July 21, 2020, 02:37:04 PM
Quote from: kphoger on July 21, 2020, 02:17:48 PM
Quote from: webny99 on July 21, 2020, 02:12:09 PM
Those percentages probably correlate roughly with the percentage of trips for which an alternate route is faster than the loop... but not the non-loop.
Doubt it.
Quote from: webny99 on July 21, 2020, 02:20:32 PM
Why else would the volumes on the loop be lower? I thought I was just stating the obvious... probably true for every loop, not just these ones.
I mean, show me such a trip–especially the pair with a 15% difference.
Google is not cooperating with me today! But, here's a potential one (https://www.google.com/maps/dir/Channahon,+IL/Rockdale,+IL+60436/@41.4644356,-88.2015868,12.25z/data=!4m15!4m14!1m5!1m1!1s0x880e889b1a8aae6f:0x30dde9f6a5963b2a!2m2!1d-88.2286735!2d41.4294753!1m5!1m1!1s0x880e63d417b9a4a5:0x1911d2110284f671!2m2!1d-88.1145036!2d41.5061419!3e0!5i1!5m1!1e1). And another (https://www.google.com/maps/dir/Speedway+Gas+Station,+23901+W+Eames+St,+Channahon,+IL+60410/Cracker+Barrel+Old+Country+Store,+Riverboat+Center+Drive,+Joliet,+IL/@41.4747205,-88.2147484,13z/data=!3m1!4b1!4m14!4m13!1m5!1m1!1s0x880e884f583be8ed:0xe816a8b93aa3c80e!2m2!1d-88.1920563!2d41.4589336!1m5!1m1!1s0x880e620847b7ef81:0xadecce31e1dfa808!2m2!1d-88.1677857!2d41.4940028!3e0!5m1!1e1). And here's one (https://www.google.com/maps/dir/Shorewood,+IL/Minooka,+IL/@41.4883446,-88.2705963,13z/data=!3m1!4b1!4m14!4m13!1m5!1m1!1s0x880e8a09256c63c1:0x7402055d4d4ea1ab!2m2!1d-88.2017293!2d41.5200305!1m5!1m1!1s0x880e8f38661ab209:0xda51ef32077eca58!2m2!1d-88.2617305!2d41.4553084!3e0!5m1!1e1) for S/W vs. E/N where Google doesn't even present the freeway as an option in the direction that requires the loop.
There's really countless localized trips that you could come up with. That extra 60-90 seconds comes into play a lot more often than you might think.
Quote from: webny99 on July 21, 2020, 03:25:34 PM
Quote from: kphoger on July 21, 2020, 02:37:04 PM
Quote from: kphoger on July 21, 2020, 02:17:48 PM
Quote from: webny99 on July 21, 2020, 02:12:09 PM
Those percentages probably correlate roughly with the percentage of trips for which an alternate route is faster than the loop... but not the non-loop.
Doubt it.
Quote from: webny99 on July 21, 2020, 02:20:32 PM
Why else would the volumes on the loop be lower? I thought I was just stating the obvious... probably true for every loop, not just these ones.
I mean, show me such a trip–especially the pair with a 15% difference.
Google is not cooperating with me today! But, here's a potential one (https://www.google.com/maps/dir/Channahon,+IL/Rockdale,+IL+60436/@41.4644356,-88.2015868,12.25z/data=!4m15!4m14!1m5!1m1!1s0x880e889b1a8aae6f:0x30dde9f6a5963b2a!2m2!1d-88.2286735!2d41.4294753!1m5!1m1!1s0x880e63d417b9a4a5:0x1911d2110284f671!2m2!1d-88.1145036!2d41.5061419!3e0!5i1!5m1!1e1). And another (https://www.google.com/maps/dir/Speedway+Gas+Station,+23901+W+Eames+St,+Channahon,+IL+60410/Cracker+Barrel+Old+Country+Store,+Riverboat+Center+Drive,+Joliet,+IL/@41.4747205,-88.2147484,13z/data=!3m1!4b1!4m14!4m13!1m5!1m1!1s0x880e884f583be8ed:0xe816a8b93aa3c80e!2m2!1d-88.1920563!2d41.4589336!1m5!1m1!1s0x880e620847b7ef81:0xadecce31e1dfa808!2m2!1d-88.1677857!2d41.4940028!3e0!5m1!1e1). And here's one (https://www.google.com/maps/dir/Shorewood,+IL/Minooka,+IL/@41.4883446,-88.2705963,13z/data=!3m1!4b1!4m14!4m13!1m5!1m1!1s0x880e8a09256c63c1:0x7402055d4d4ea1ab!2m2!1d-88.2017293!2d41.5200305!1m5!1m1!1s0x880e8f38661ab209:0xda51ef32077eca58!2m2!1d-88.2617305!2d41.4553084!3e0!5m1!1e1) for S/W vs. E/N where Google doesn't even present the freeway as an option in the direction that requires the loop.
There's really countless localized trips that you could come up with. That extra 60-90 seconds comes into play a lot more often than you might think.
And if I am on 6 by Youngs Rd, I get on 80 at Houbolt Rd.
Hoping this isn't too off topic, but what's been the best replacement for these? Stacks?
Quote from: OCGuy81 on July 23, 2020, 02:44:16 PM
Hoping this isn't too off topic, but what's been the best replacement for these? Stacks?
Only if you have the space and the money.
Quote from: stridentweasel on July 23, 2020, 08:53:25 PM
Quote from: OCGuy81 on July 23, 2020, 02:44:16 PM
Hoping this isn't too off topic, but what's been the best replacement for these? Stacks?
Only if you have the space and the money.
If one can live with 35-40 mph ramps, turbine interchanges work reasonably well. I still think cloverleaves with C/D lanes for both facilities work fine in rural situations (the I-22/269 interchange in NW MS is an example of such -- although I would have liked to have seen them modify it with a WB>SB flyover; also, the I-95/future 87 interchange in NC will probably remain a double-CD cloverleaf).
I think that, for most situations, adding one or two flyover ramps is fine. Generally, not all four accel/decel crunch points are equally bad, and a couple of them might as well remain as-is.
Quote from: OCGuy81 on July 23, 2020, 02:44:16 PM
Hoping this isn't too off topic, but what's been the best replacement for these? Stacks?
It depends on the overall interchange. If the cross road is a local roadway and isn't that busy, a diamond or some variation thereof would work fine. If you desire freeflow movements on both roadways, the turbine or stack are better, but they also come at a much higher cost.
There's also the consideration of where to place the ramps, especially if you don't close down any point of the interchange. Working with a clean slate is easy; working around existing ramps is quite a bit more challenging.
Some are fine with the addition of C/D lanes, some with added direct ramps and some, if they are with surface roads, with more conventional style service interchanges.
Mike
It seems as if, with the presence of C/D lanes, the cloverleaf interchange -- if laid out with medium-high speed (>30-35 mph) loop ramps -- may still be a viable cost-cutting choice for rural "system" interchanges between limited-access facilities. But I'd be willing to wager that there will be no more pure cloverleaves built as interchanges between freeways/expressways and surface roads.
I don't remember where I saw it, but one plan I saw for the new interchange between I-95 and I-42 used a cloverleaf, with C/D lanes for I-95, IIRC. It seems that the cloverleaf kind of still is in fashion, just in a different form.
^ Perhaps this one (https://jocoreport.com/wp-content/uploads/2017/09/Conceptual-design-of-95-and-70-interchnage.pdf)? (from a Johnston County newspaper article)
In Texas, it was sometime in the early 90s. I remember a cloverleaf being built in the 80s, but since the 90s on, not only do they not build any more cloverleafs, they don't build any parclos nor do they build any more intersections at all that have any kind of loop in the exit/entrance ramp. Plus, many old cloverleafs are being torn down for complete stack interchanges (with the exception of the new Loop 375/I-10 intersection in El Paso, where they built a stack and just left the old cloverleaf there). Seeing a cloverleaf in Texas today is like seeing a white whale.
Quote from: froggie on July 26, 2020, 08:42:09 PM
^ Perhaps this one (https://jocoreport.com/wp-content/uploads/2017/09/Conceptual-design-of-95-and-70-interchnage.pdf)? (from a Johnston County newspaper article)
That's exactly the one. It has I-95 swerving east so they can build an intersection with future I-42 (currently Bypass 70) that's a cloverleaf in the middle of what's now an open field with a bunch of solar panels in the middle of it. I just remember being amused when I first saw it: "they still design cloverleafs?"
Quote from: silverback1065 on June 07, 2020, 09:46:24 PM
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.
Without reading the rest of this thread (yet) (I rarely visit the boards that aren't Northeast or Mid-Atlantic), I'll point out that I-695 in MD had three full clovers within +/- 2 miles (clockwise, MD 41, MD 147, and US 1 in the Parkville/Carney stretch). Then the MD 147 interchange was slightly reconfigured, but you must still risk weaving on the counterclockwise loop at 147.
At least PennDOT has CD roads on 95 at the (still) full clover at PA 420 south of the Philly airport. Plenty of room IMO for that interchange, and the CDs have been there since day one in 1972(?).
ixnay
Arizona is a state where they never were really in fashion but have now completely fallen out of fashion.
I believe Arizona used to have 3 full cloverleafs:
I-17 / I-40 / AZ89A (former US89A) in Flagstaff
I-17 / Deer Valley Rd in Phoenix
I-17 / Bell Rd in Phoenix
All 3 are no longer full cloverleafs. I-17 / Bell Rd. is a diamond. I-17 / Deer Valley Rd is now a parclo. I-17 / I-40 / AZ89A has 2 loops, 1 flyover, and 1 right exit / left entrance ramp now.
Arizona doesn't even like parclos very much as it removed them completely at I-17 / Thunderbird Rd, I-19 / Ajo Way, I-19 / Valencia Rd, I-10 / Valencia Rd.
Arizona also never built the parclo that it intended to built at I-19 / Irvington Rd. The only recent build Arizona parclos are I-17 / AZ 74 and the "folded diamond" at US 60 / Meridian Rd
In addition, Arizona has also been steadily removing trumpet interchanges.
I've definitely thought about this for WA, but never put pen-to-paper:
The major full cloverleafs in Washington State right now are as follows:
1960s:
* I-5 @ JBLM Main & North Gates (Exit 120)
* I-5 @ S 56 St (Tacoma; Exit 130)
* I-405 @ NE 8 St (Bellevue; Exit 13B)
* WA-99 @ Des Moines Dr/14 Ave S (South Seattle)
1970s:
* I-205 @ WA-500 (Vancouver; Exit 30)
* I-405 @ NE 85 St (Kirkland; Exit 18)
* I-182/US-12 @ US-395 (Pasco; Exit 14)
* I-90 @ 148/150 Ave SE (Bellevue; Exit 11)
As far as when I believe it officially died in Washington State (since that's sort of the point of this thread), I would trace it to the late 1990s when I-5 @ WA-512 (https://www.google.com/maps/@47.1631171,-122.4795835,499m/data=!3m1!1e3) in Lakewood was reconfigured into a partial cloverleaf. The western loop ramps were conflicting with each other very heavily, so the southwest loop ramp was replaced with a triple left turn. However, no knew cloverleafs have been built since the 1970s, to my knowledge, so the late 1970s is when they fell out of fashion.
tl;dr... the negatives of cloverleafs in WA were clear by the late 1970s, and they stopped building them; by the 1990s, their issues became serious enough to warrant their reconstruction, primarily into partial cloverleafs. This practice continues today.
Following the modification at I-5 & WA-512 in the late 1990s, many cloverleafs in WA were modified to remove ramps, including...
* I-5 @ S 38 St (Tacoma; Exit 132), modified in 2001 into a Parclo B4
* I-405 @ WA-167 (Renton, Exit 2), modified in 2002 and 2018 with flyover ramps
* I-5 @ WA-18 (Federal Way, Exit 142), modified in 2012 into a cloverstack
Quote from: ztonyg on August 05, 2020, 12:49:19 AM
Arizona is a state where they never were really in fashion but have now completely fallen out of fashion.
I believe Arizona used to have 3 full cloverleafs:
I-17 / I-40 / AZ89A (former US89A) in Flagstaff
I-17 / Deer Valley Rd in Phoenix
I-17 / Bell Rd in Phoenix
All 3 are no longer full cloverleafs. I-17 / Bell Rd. is a diamond. I-17 / Deer Valley Rd is now a parclo. I-17 / I-40 / AZ89A has 2 loops, 1 flyover, and 1 right exit / left entrance ramp now.
Arizona doesn't even like parclos very much as it removed them completely at I-17 / Thunderbird Rd, I-19 / Ajo Way, I-19 / Valencia Rd, I-10 / Valencia Rd.
Arizona also never built the parclo that it intended to built at I-19 / Irvington Rd. The only recent build Arizona parclos are I-17 / AZ 74 and the "folded diamond" at US 60 / Meridian Rd
In addition, Arizona has also been steadily removing trumpet interchanges.
Some parclos still exist on I-10 from Benson east to the New Mexico state line, in Wilcox, Bowie and San Simon.
I remember we used to have a Clover I-70 and I-75 near Dayton
Wish I could tell you. They're still built pretty regularly in NC.
As stated by
sprjus4.
Quote from: sprjus4 on June 09, 2020, 04:03:25 AM
A few in North Carolina in the past couple decades -
- I-95 / I-795 / US-264 (C/D roads on I-95) - around 2006
- US-264 / NC-11 Bypass - 2019
- US-70 / US-17 (only partially in use, stub on north side) - around 2012
- I-95 / I-74 (C/D roads on I-95) - around 2008
- US-1 / US-421 (C/D roads on US-421) - around 2008
- I-85 / I-73 (C/D roads on both) - around 2006
- I-85 / US-421 (C/D roads on both, one flyover) - around 2006
I recently found out that the Town of Brookhaven did something really dumb with an interchange on NY 27. They installed the entrance to a park on the on-ramp from Suffolk CR 51 to the eastbound NY 27 service road. As if building an intersection too close to a ramp doesn't already increase the risk of accidents, and renders cloverleafs more dysfunctional.
https://goo.gl/maps/yRCpL9phJZpsUmAD6
Quote from: D-Dey65 on August 16, 2020, 09:25:51 PM
I recently found out that the Town of Brookhaven did something really dumb with an interchange on NY 27. They installed the entrance to a park on the on-ramp from Suffolk CR 51 to the eastbound NY 27 service road. As if building an intersection too close to a ramp doesn't already increase the risk of accidents, and renders cloverleafs more dysfunctional.
https://goo.gl/maps/yRCpL9phJZpsUmAD6
Huh? That's just a frontage road. There's thousands of examples of businesses built with entrances to frontage roads.
Quote from: jakeroot on August 18, 2020, 12:25:44 AM
Quote from: D-Dey65 on August 16, 2020, 09:25:51 PM
I recently found out that the Town of Brookhaven did something really dumb with an interchange on NY 27. They installed the entrance to a park on the on-ramp from Suffolk CR 51 to the eastbound NY 27 service road. As if building an intersection too close to a ramp doesn't already increase the risk of accidents, and renders cloverleafs more dysfunctional.
https://goo.gl/maps/yRCpL9phJZpsUmAD6
Huh? That's just a frontage road. There's thousands of examples of businesses built with entrances to frontage roads.
Actually, that's a partial cloverleaf.
Quote from: D-Dey65 on August 18, 2020, 11:11:18 AM
Quote from: jakeroot on August 18, 2020, 12:25:44 AM
Quote from: D-Dey65 on August 16, 2020, 09:25:51 PM
I recently found out that the Town of Brookhaven did something really dumb with an interchange on NY 27. They installed the entrance to a park on the on-ramp from Suffolk CR 51 to the eastbound NY 27 service road. As if building an intersection too close to a ramp doesn't already increase the risk of accidents, and renders cloverleafs more dysfunctional.
https://goo.gl/maps/yRCpL9phJZpsUmAD6
Huh? That's just a frontage road. There's thousands of examples of businesses built with entrances to frontage roads.
Actually, that's a partial cloverleaf.
It's a partial cloverleaf that exits/enters a service road.
The park entrance is on the service road. The exit ramp to the west of the park ends at the cross street; it has a stop sign. If you go straight through you're on the service road. The loop ramp never touches the service road.
Quote from: GaryV on August 18, 2020, 12:51:46 PM
Quote from: D-Dey65 on August 18, 2020, 11:11:18 AM
Quote from: jakeroot on August 18, 2020, 12:25:44 AM
Quote from: D-Dey65 on August 16, 2020, 09:25:51 PM
I recently found out that the Town of Brookhaven did something really dumb with an interchange on NY 27. They installed the entrance to a park on the on-ramp from Suffolk CR 51 to the eastbound NY 27 service road. As if building an intersection too close to a ramp doesn't already increase the risk of accidents, and renders cloverleafs more dysfunctional.
https://goo.gl/maps/yRCpL9phJZpsUmAD6
Huh? That's just a frontage road. There's thousands of examples of businesses built with entrances to frontage roads.
Actually, that's a partial cloverleaf.
It's a partial cloverleaf that exits/enters a service road.
The park entrance is on the service road. The exit ramp to the west of the park ends at the cross street; it has a stop sign. If you go straight through you're on the service road. The loop ramp never touches the service road.
Agreed. The park access lies between a stop sign and a stoplight. Hardly "something really dumb".
Exiting traffic to CH-51 SB would not drive past that entrance.
Exiting traffic to CH-51 NB would not drive past that entrance.
Exiting traffic to CH-55 would not drive past that entrance.
Entering traffic from CH-55 would not drive past that entrance.
Entering traffic from CH-51
would drive past that entrance, but that's no more "dumb" than their also having to go through a stoplight at CH-55.