Why does the Bay Area have so many cloverleafs?

[kernals12]

Highway engineers these days hate cloverleafs. They are seen as sources of congestion and accidents due to the weaving between vehicles entering and exiting. Many of them have been converted into Parclos on freeway arterial interchanges or into cloverstacks on freeway-freeway interchanges. But if you look at Google Maps, you see that the Bay Area still has tons of them, even at the extremely busy 880-101 interchange. So what is responsible for this situation? It seems like getting rid of them would be a fairly simple way to increase traffic capacity and safety.

[Max Rockatansky]

Are you effing kidding me?  What is your malfunction with this obsession with trashing the San Francisco Bay Area?  Are things just that peachy and rosy in Massachusetts that you can't let some place your family has origins go?

[kernals12]

Are you effing kidding me?  What is your malfunction with this obsession with trashing the San Francisco Bay Area?  Are things just that peachy and rosy in Massachusetts that you can't let some place your family has origins go?

I wasn't being snarky. I was just asking.

[hotdogPi]

Massachusetts has a whole bunch of cloverleaves, too.

[kernals12]

Massachusetts has a whole bunch of cloverleaves, too.

I know, I've had the pleasure of being one of those sad commuters using the I-93/I-95 interchange in Reading.

[Max Rockatansky]

Are you effing kidding me?  What is your malfunction with this obsession with trashing the San Francisco Bay Area?  Are things just that peachy and rosy in Massachusetts that you can't let some place your family has origins go?

I wasn't being snarky. I was just asking.

But come off that way by the way you phrase things, especially when you look at the cumulative sum of what you have said regarding the Bay Area (the thread last night in particular was very clear regarding your opinions).  To that end I too don't necessarily agree with how highway based transportation in the Bay has been historically handled, especially when it comes to a new crossing of San Francisco Bay.  I'm also not a fan of proposing tolls for State Highways that have always been free (especially 37 and 12).  But to than end I don't live in the Bay Area and I can't do much as a non-resident in terms of fighting things like that.

About the best thing I can think to do is talk about those issues in a realistic and tactful manner.  About as political as I ever have really gotten with the road community in California was getting behind SB1 a couple years ago.  The irony there was that SB1 was being contested heavily in the Central Valley due to a certain set portions of the funds drawn being set aside for the HSR.  For my part I saw the benefits of SB1 in terms of highway reinvestment as far out weighing any benefits to the HSR.  For what it's worth, I don't know if I changed anyone's opinion but I can say that District 6 seems to have benefited greatly from SB1.  That in my opinion is how you should be approaching issues like what you see in the San Francisco Bay Area.  Try to understand that for every single good Highway idea there are a lot of really bad ones that have come up also.  You have a lot of distrust towards highway development due to the FritzOwl level of dystopian ideas the Division of Highways once had for San Francisco. 

The real answer your question above is that facilities are old and Caltrans District 4 doesn't have the funding to upgrade them.  For whatever reason (which may be illustrated above) District 4 seems to be not too interested in using things like SB1 for stuff like ramp replacements and signage upgrades.  Really the only true development you'll see widely in the Bay Area right now is the construction of toll lanes on I-880/Nimitz Freeway and I-680.

[kkt]

It's not that complicated.  The Bay Area started building freeways early, so a lot of cloverleafs were built.  They've been playing catchup forever, trying to do seismic retrofits and repair earthquake damage and add capacity where possible.  Real estate and construction costs are high so only a few projects can get worked on.  Some of the interchanges with poor geometry have been addressed, but there's plenty left.

[kernals12]

It's not that complicated.  The Bay Area started building freeways early, so a lot of cloverleafs were built.  They've been playing catchup forever, trying to do seismic retrofits and repair earthquake damage and add capacity where possible.  Real estate and construction costs are high so only a few projects can get worked on.  Some of the interchanges with poor geometry have been addressed, but there's plenty left.

Cloverleaf take up a lot of space, so using more space efficient designs could free up valuable land

[DTComposer]

You are not factually correct. A quick scan of the nine Bay Area counties shows that fewer than 7% of the interchanges are three or four-loop cloverleaf designs. There used to be more, but again, actual research shows that many of them have been converted to parclos or other designs, just as you have suggested.

(there is a small margin of error possible here, since this involved my going through the interchange lists and comparing them to maps)

I'm not going to spend a lot of time on your blatant and immature bias against a region that you don't have any actual experience living in, but if you're going to show your bias, at least get your facts straight.

[STLmapboy]

The Bay Area really doesn't have that many cloverleaves. It's more than most of the west coast, but less than much of the rest of the country (New England and the east coast being the most prolific in this regard). In the Midwest, Minnesota has quite a few, as does Wisconsin.

[jrouse]

The reason why 880-101 hasn't been rebuilt is cost.
It would be extremely expensive to put in flyovers in such a heavily urbanized area. 

[kkt]

Yes, it's cost, also there are other interchanges too close to 880-101 for good practice.  To meet current best practices they'd probably have to rebuild a mile from the actual interchange in each direction with collector-distributor roads.  Which is part of the reason the cost is so high...

[bing101]

I-780 @ I-80 interchange is cloverleaf. But that was when I-80 was then co-signed with  US-40.

[jrouse]

Yes, it's cost, also there are other interchanges too close to 880-101 for good practice.  To meet current best practices they'd probably have to rebuild a mile from the actual interchange in each direction with collector-distributor roads.  Which is part of the reason the cost is so high...

Yes, I should have been more specific.  It is for these reasons that you would need long, expensive flyovers. 

[Revive 755]

The Bay Area really doesn't have that many cloverleaves. It's more than most of the west coast, but less than much of the rest of the country (New England and the east coast being the most prolific in this regard). In the Midwest, Minnesota has quite a few, as does Wisconsin.

Could be mistaken, but I think Illinois has and generally used more than Wisconsin did.  I'm only finding I-43 at WI 100 around Milwaukee, possibly a few extinct once planned ones on I-94 south of I-894, whereas Chicagoland has multiple cloverleafs in a row on some corridors (I-55 east of I-355 for a bit).  They were also heavily used in other parts of Illinois (three in a row on I-55 in Springfield, usually at least one in the other decent sized areas).  Wisconsin seems quite good at removing the ones they had.

I think Indiana may have also had more the Wisconsin until many of them were reconfigured into other interchange types.

[myosh_tino]

Cloverleaf take up a lot of space, so using more space efficient designs could free up valuable land

It's funny you say this because of your reference to the 880-101 interchange in San Jose.  The main reason why that interchange hasn't been upgraded is because there is not enough space to build a couple of simple flyovers no less a full stack without having to "eminent domain" a significant number of properties around it.

[kernals12]

Cloverleaf take up a lot of space, so using more space efficient designs could free up valuable land

It's funny you say this because of your reference to the 880-101 interchange in San Jose.  The main reason why that interchange hasn't been upgraded is because there is not enough space to build a couple of simple flyovers no less a full stack without having to "eminent domain" a significant number of properties around it.

For freeway to arterial interchanges, SPUIs, Diamonds, Parclos, or DDIs would require less space than a Cloveleaf.

[kkt]

Cloverleaf take up a lot of space, so using more space efficient designs could free up valuable land

It's funny you say this because of your reference to the 880-101 interchange in San Jose.  The main reason why that interchange hasn't been upgraded is because there is not enough space to build a couple of simple flyovers no less a full stack without having to "eminent domain" a significant number of properties around it.

For freeway to arterial interchanges, SPUIs, Diamonds, Parclos, or DDIs would require less space than a Cloveleaf.

880 to 101 would be a freeway to freeway interchange.  It would also be somewhat limited in height due to the approach paths for San Jose Airport.

[mapman]

880 to 101 would be a freeway to freeway interchange.  It would also be somewhat limited in height due to the approach paths for San Jose Airport.

kkt is correct - the San Jose airport is the primary reason for the lack of an upgrade to this interchange.  You can't add ramps above the interchange due to the approach paths to the airport.  (This is also why there isn't an interchange between I-880 and CA 87.)  Also, you can't put ramps below the interchange due to the high water table in that area.  US 101 (the lower of the two freeways) has intermittent pavement flooding problems, despite Caltrans having multiple pumps to keep the roadway dry.  So, we're stuck with the cloverleaf configuration.   

[skluth]

The Bay Area really doesn't have that many cloverleaves. It's more than most of the west coast, but less than much of the rest of the country (New England and the east coast being the most prolific in this regard). In the Midwest, Minnesota has quite a few, as does Wisconsin.

Could be mistaken, but I think Illinois has and generally used more than Wisconsin did.  I'm only finding I-43 at WI 100 around Milwaukee, possibly a few extinct once planned ones on I-94 south of I-894, whereas Chicagoland has multiple cloverleafs in a row on some corridors (I-55 east of I-355 for a bit).  They were also heavily used in other parts of Illinois (three in a row on I-55 in Springfield, usually at least one in the other decent sized areas).  Wisconsin seems quite good at removing the ones they had.

I think Indiana may have also had more the Wisconsin until many of them were reconfigured into other interchange types.

I grew up in Wisconsin and thought there were a fair number of cloverleafs. I-43@WI 23. I-90/94@US 151. I-94@US 53. US 53@WI 29 is one of the more wacko cloverleafs I've seen. I-43@I-90 (from back when it was WI 15@I-90). I wish they had built one at US/I-41@US 151 instead of the stupid diamond interchange plopping a couple stop lights on what is otherwise a non-stop drive from Madison to Green Bay.

[silverback1065]

Are you effing kidding me?  What is your malfunction with this obsession with trashing the San Francisco Bay Area?  Are things just that peachy and rosy in Massachusetts that you can't let some place your family has origins go?

I wasn't being snarky. I was just asking.

But come off that way by the way you phrase things, especially when you look at the cumulative sum of what you have said regarding the Bay Area (the thread last night in particular was very clear regarding your opinions).  To that end I too don't necessarily agree with how highway based transportation in the Bay has been historically handled, especially when it comes to a new crossing of San Francisco Bay.  I'm also not a fan of proposing tolls for State Highways that have always been free (especially 37 and 12).  But to than end I don't live in the Bay Area and I can't do much as a non-resident in terms of fighting things like that.

About the best thing I can think to do is talk about those issues in a realistic and tactful manner.  About as political as I ever have really gotten with the road community in California was getting behind SB1 a couple years ago.  The irony there was that SB1 was being contested heavily in the Central Valley due to a certain set portions of the funds drawn being set aside for the HSR.  For my part I saw the benefits of SB1 in terms of highway reinvestment as far out weighing any benefits to the HSR.  For what it's worth, I don't know if I changed anyone's opinion but I can say that District 6 seems to have benefited greatly from SB1.  That in my opinion is how you should be approaching issues like what you see in the San Francisco Bay Area.  Try to understand that for every single good Highway idea there are a lot of really bad ones that have come up also.  You have a lot of distrust towards highway development due to the FritzOwl level of dystopian ideas the Division of Highways once had for San Francisco. 

The real answer your question above is that facilities are old and Caltrans District 4 doesn't have the funding to upgrade them.  For whatever reason (which may be illustrated above) District 4 seems to be not too interested in using things like SB1 for stuff like ramp replacements and signage upgrades.  Really the only true development you'll see widely in the Bay Area right now is the construction of toll lanes on I-880/Nimitz Freeway and I-680.

you do know that he just wrote text and you really can't tell what his emotions are right? texting is the worst form of communication and assuming a persons emotions from text is ill advised. emojis help but it's still not perfect.

[Max Rockatansky]

Are you effing kidding me?  What is your malfunction with this obsession with trashing the San Francisco Bay Area?  Are things just that peachy and rosy in Massachusetts that you can't let some place your family has origins go?

I wasn't being snarky. I was just asking.

But come off that way by the way you phrase things, especially when you look at the cumulative sum of what you have said regarding the Bay Area (the thread last night in particular was very clear regarding your opinions).  To that end I too don't necessarily agree with how highway based transportation in the Bay has been historically handled, especially when it comes to a new crossing of San Francisco Bay.  I'm also not a fan of proposing tolls for State Highways that have always been free (especially 37 and 12).  But to than end I don't live in the Bay Area and I can't do much as a non-resident in terms of fighting things like that.

About the best thing I can think to do is talk about those issues in a realistic and tactful manner.  About as political as I ever have really gotten with the road community in California was getting behind SB1 a couple years ago.  The irony there was that SB1 was being contested heavily in the Central Valley due to a certain set portions of the funds drawn being set aside for the HSR.  For my part I saw the benefits of SB1 in terms of highway reinvestment as far out weighing any benefits to the HSR.  For what it's worth, I don't know if I changed anyone's opinion but I can say that District 6 seems to have benefited greatly from SB1.  That in my opinion is how you should be approaching issues like what you see in the San Francisco Bay Area.  Try to understand that for every single good Highway idea there are a lot of really bad ones that have come up also.  You have a lot of distrust towards highway development due to the FritzOwl level of dystopian ideas the Division of Highways once had for San Francisco. 

The real answer your question above is that facilities are old and Caltrans District 4 doesn't have the funding to upgrade them.  For whatever reason (which may be illustrated above) District 4 seems to be not too interested in using things like SB1 for stuff like ramp replacements and signage upgrades.  Really the only true development you'll see widely in the Bay Area right now is the construction of toll lanes on I-880/Nimitz Freeway and I-680.

you do know that he just wrote text and you really can't tell what his emotions are right? texting is the worst form of communication and assuming a persons emotions from text is ill advised. emojis help but it's still not perfect.

I refer to:

https://www.aaroads.com/forum/index.php?topic=27559.msg2529175#msg2529175

Suffice to say, a lot can be inferred after reading the "rant."   And to that end, I disagree.  I've taken written statements from people for twenty years and there certainly is a lot you can take from written word.  You can clearly convey emotions, infer them, or even subtly sneak them into writing.

[STLmapboy]

Are you effing kidding me?  What is your malfunction with this obsession with trashing the San Francisco Bay Area?  Are things just that peachy and rosy in Massachusetts that you can't let some place your family has origins go?

I wasn't being snarky. I was just asking.

But come off that way by the way you phrase things, especially when you look at the cumulative sum of what you have said regarding the Bay Area (the thread last night in particular was very clear regarding your opinions).  To that end I too don't necessarily agree with how highway based transportation in the Bay has been historically handled, especially when it comes to a new crossing of San Francisco Bay.  I'm also not a fan of proposing tolls for State Highways that have always been free (especially 37 and 12).  But to than end I don't live in the Bay Area and I can't do much as a non-resident in terms of fighting things like that.

About the best thing I can think to do is talk about those issues in a realistic and tactful manner.  About as political as I ever have really gotten with the road community in California was getting behind SB1 a couple years ago.  The irony there was that SB1 was being contested heavily in the Central Valley due to a certain set portions of the funds drawn being set aside for the HSR.  For my part I saw the benefits of SB1 in terms of highway reinvestment as far out weighing any benefits to the HSR.  For what it's worth, I don't know if I changed anyone's opinion but I can say that District 6 seems to have benefited greatly from SB1.  That in my opinion is how you should be approaching issues like what you see in the San Francisco Bay Area.  Try to understand that for every single good Highway idea there are a lot of really bad ones that have come up also.  You have a lot of distrust towards highway development due to the FritzOwl level of dystopian ideas the Division of Highways once had for San Francisco. 

The real answer your question above is that facilities are old and Caltrans District 4 doesn't have the funding to upgrade them.  For whatever reason (which may be illustrated above) District 4 seems to be not too interested in using things like SB1 for stuff like ramp replacements and signage upgrades.  Really the only true development you'll see widely in the Bay Area right now is the construction of toll lanes on I-880/Nimitz Freeway and I-680.

you do know that he just wrote text and you really can't tell what his emotions are right? texting is the worst form of communication and assuming a persons emotions from text is ill advised. emojis help but it's still not perfect.

I refer to:

https://www.aaroads.com/forum/index.php?topic=27559.msg2529175#msg2529175

Suffice to say, a lot can be inferred after reading the "rant."   And to that end, I disagree.  I've taken written statements from people for twenty years and there certainly is a lot you can take from written word.  You can clearly convey emotions, infer them, or even subtly sneak them into writing.

Surely you understand that what you put was a bit on the long side, though, right? It's better than kernals' linked braindump, for sure, but it's still a bit of a tl;dr situation.

[Max Rockatansky]

Are you effing kidding me?  What is your malfunction with this obsession with trashing the San Francisco Bay Area?  Are things just that peachy and rosy in Massachusetts that you can't let some place your family has origins go?

I wasn't being snarky. I was just asking.

But come off that way by the way you phrase things, especially when you look at the cumulative sum of what you have said regarding the Bay Area (the thread last night in particular was very clear regarding your opinions).  To that end I too don't necessarily agree with how highway based transportation in the Bay has been historically handled, especially when it comes to a new crossing of San Francisco Bay.  I'm also not a fan of proposing tolls for State Highways that have always been free (especially 37 and 12).  But to than end I don't live in the Bay Area and I can't do much as a non-resident in terms of fighting things like that.

About the best thing I can think to do is talk about those issues in a realistic and tactful manner.  About as political as I ever have really gotten with the road community in California was getting behind SB1 a couple years ago.  The irony there was that SB1 was being contested heavily in the Central Valley due to a certain set portions of the funds drawn being set aside for the HSR.  For my part I saw the benefits of SB1 in terms of highway reinvestment as far out weighing any benefits to the HSR.  For what it's worth, I don't know if I changed anyone's opinion but I can say that District 6 seems to have benefited greatly from SB1.  That in my opinion is how you should be approaching issues like what you see in the San Francisco Bay Area.  Try to understand that for every single good Highway idea there are a lot of really bad ones that have come up also.  You have a lot of distrust towards highway development due to the FritzOwl level of dystopian ideas the Division of Highways once had for San Francisco. 

The real answer your question above is that facilities are old and Caltrans District 4 doesn't have the funding to upgrade them.  For whatever reason (which may be illustrated above) District 4 seems to be not too interested in using things like SB1 for stuff like ramp replacements and signage upgrades.  Really the only true development you'll see widely in the Bay Area right now is the construction of toll lanes on I-880/Nimitz Freeway and I-680.

you do know that he just wrote text and you really can't tell what his emotions are right? texting is the worst form of communication and assuming a persons emotions from text is ill advised. emojis help but it's still not perfect.

I refer to:

https://www.aaroads.com/forum/index.php?topic=27559.msg2529175#msg2529175

Suffice to say, a lot can be inferred after reading the "rant."   And to that end, I disagree.  I've taken written statements from people for twenty years and there certainly is a lot you can take from written word.  You can clearly convey emotions, infer them, or even subtly sneak them into writing.

Surely you understand that what you put was a bit on the long side, though, right? It's better than kernals' linked braindump, for sure, but it's still a bit of a tl;dr situation.

The least I could do was ask for the annoying angst for the Bay Area bashing to stop.  I'm all for constructive criticism of any given area, but that hasn't what OP has been putting forth thus far on the forum.  At this point these threads have swung to something more productive in spite of despite what the intentions may have been at the beginning.  At this point commenting on it further probably doesn't amount to much if we can stay on track with the topics on this board.

[sparker]

^^^^^^^^^^^
Much of the overall criticism directed at the state of transportation (including highways, of course) in the Bay Area can be attributed to the prioritizations of particular modes and objectives by the combination of the various agencies that contribute or even "vet" the projects that are presented to their collective planners -- and how the area's legislators (all the way from city councils and county supervisors to state assemblypersons and senators) can and do function as an effective "valve" on the project pipeline.  When I first resided in the South Bay (1975-86) there was always some level of bias toward collective transit and against expansion of facilities for individual/commercial automotive travel -- but at that time it wasn't sufficient to derail major road projects such as the planning and ROW acquisition for the CA 85 freeway and the slow but steady progress on CA 87.  However, there was always a bit of mitigation involved, such as the truck ban on 85 south of I-280 and the narrowing of that facility between CA 17 and I-280 from 4 overall lanes (including one HOV) down to 3, including the HOV; but that was largely attributed to Saratoga/Los Gatos NIMBY's putting their 200 cents in! 

More recently both San Jose (city) and Santa Clara (county) planners are firmly in the "urbanism" camp, and since projects within metro bounds are vetted by all agencies, not just Caltrans, priorities as well have changed -- and unless there's a specific safety issue, older interchange modifications generally are well down the "to do" list.  But this is not a specific Bay Area issue -- and while this area was among the first to manifest this sea change in priorities, it has certainly been matched elsewhere in the state, like L.A. and its virtual new-freeway ban in the L.A. basin; and definitely with Sacramento, which hasn't seen a completely new freeway facility (although CA 99 was upgraded to a full freeway north of I-5) since 1981, when I-5 was completed south of town.  And here in San Jose, one can witness first-hand that priority switch with the in-progress electrification of the Caltrans commute rail line (those facilities to be shared with HSR if and when it ever gets here!), a project well into the hundreds of millions.  But right now one long-pressing road/connectivity issue is being considered -- reconstructing the CA 262 Mission Blvd. connection between I-880 and I-680 into a full freeway to eliminate a peak-hour bottleneck in the Warm Springs area that affects local traffic as well -- a situation that has prompted renewed public interest in the concept.  We'll just have to see what transpires regarding both whether such a project gets out of the starting blocks and how timely the funding process plays out.  262 is one case where the concept of "induced demand" is a ship that sailed when the original CA 237 freeway connecting the two N-S Interstates was cancelled -- about 3 out of 4 drivers heading to I-680 and points beyond (Pleasanton, Livermore, Tracy, etc.) crowd onto 262 since it's the shortest connection between the freeways.  So far there's been no massive or even vocal pissing and moaning from the "woke" and/or urbanist sector regarding the preliminary planning/design for the freeway upgrade; we'll see what happens when a final design is completed and proffered. 

But while the upper reaches of US 101 -- particularly in San Mateo County -- have seen little changes to the original late-50's/early-60's interchange configurations, the three high-traffic former cloverleafs -- Trimble/De La Cruz (county G6), San Tomas Expressway (G4), and Lawrence Expressway (G2) have been partially reconfigured in the last couple of decades; the first is now a standard parclo for NB 101 but retained the double-loop cloverleaf for SB 101 (sans C/D lanes and thus a traffic PITA!); the other ones are now cookie-cutter parclos.  Whether these mods are extended northward at some point is yet TBD -- but at least some progress has been made.