Types of Partial Cloverleaf Compared! - ParClo Interchange Comparison 

Just a possible fun fact But the A in A2 probably stands for "ante" This is a latin word for "before" and is often used in older words like AM: Ante Meridium (Before Noon) Antechamber (self explanatory) But also modern words such as: "To anti-cipate" or an "antecedent" ... maybe :P

I love that Cities:Skylines has achieved the unthinkable in many cases: a fantastic non-violent game that can genuinely educate and excite people about some really mundane but important subjects like intersection conflict points, zoning rights, noise pollution, economic drivers of cities, and where traffic really comes from.

I think in real life this AB2 is build, as it saves space, sometimes you have already buildings on one side of the road and from city planning, they might be both at the same side.

AB2 is my exit off the highway in my hometown lol. It works fine because in my location traffic is very asymmetric. Most of civilization lives “south” of the exit (as you have it set up) and only a little bit is north. There’s a light at the southern intersection and there’s no light at the northern one Edit: my mistake, yes there is a light at the northern intersection one but it’s almost alway green until someone sits waiting to get off the highway and turn left (north)

I think the ab2 would be acceptable if the arteriel is ending at that point (or there is at least heavely asymmetric traffic) and you have no space for diagonal opposed leaves.

As to A4 and B4 with roundabouts, the volume of traffic is sort of swapping, so in the regular B4 (without roundabouts) the left turns accure from the "inside" of the arterial (on the bridge) and slow the traffic, but with a roundabout you give priority to the left turn, and slowing down traffic from the outside of the arterial. i would even consider A4 with roundabout that for the same reasoning, act very similar to B4 without roundabout.

One way to remove pressure on the AB4 would be to remove the pinch point at the offramp. You have a single lane leaving the highway, splitting into two lanes where one turns right and one left when they hit the regular street. Obviously the left turn at that junction is the blocker, so if that was two lanes from the highway where traffic could chose if it was going left or right by getting in lane while still *on* the highway, then things trying to make a right turn wouldn't be sat behind things waiting for their opportunity to turn left. I'm not sure that the cim AI would understand the concept tho, and might just queue on the highway anyway.

I've been quite sad and down lately and every time you upload I get to forget about the stuff that's going on in my life for 10-20 minutes. Thank you

In a rural situation, just plop down a roundabout and you're good to go! That's like the aproach Norway uses everywhere. The most complicated junction here is called 'Sinsenkrysset' and is a three level roundabout.

I just want to say that because of your videos on Parclos, and also the SPUI on another recent video, my cities look better, function better, and they are, again, thanks to your guidance, really quite easy to build. I do like the B4, I need to sit down and try the roundabout version though.

Love it! I think you identified the difference between A4 and B4 correctly, B4 has 2 lanes entering and 1 lane exiting per intersection. A4 has 2 lanes exiting and 1 entering. The largest contributor to the preference is probably the road real estate difference between them, as the preferred direction can split its traffic over two lanes (slip lane and lane from other junction). I've seen AB2s being used at less rural areas, but they often have a light, with multiple dedicated turning lanes just to allow traffic to wait without backing up into the intersection (so you'd have 3 lanes to turn right onto a 3 lane road for example). The AB2 is probably only good in the scenario where you can't build on one side of the road, or need smaller footprint (wider roads are easier than new roads). I've never seen an AB4 though.

The numbers in A2, B2, AB2, A4, B4 or AB4 stand for the number of quadrants (with the highway and the arterial road dividing these quadrants) that have ramps in them, not the number of ramps themselves. I've also noticed I've got the chevrons on one junction of the Cloverleaf pointing the wrong way. I'll adjust!! :)

In terms of the AB2, if the highway is crossing a river and the road is parallel to said river, you might have no choice but to use an AB2. There is an interchange in Portland, Oregon which does this and for this reason, I believe. Only it’s not a service interchange, it’s two highways…. But it’s the same idea in that the river forced design decisions. I think it’s where the 205 crosses the 14. I drove it once with my dad on a trip from Mexico to Canada. I grew up in a very rural part of the world… interchanges blow my mind. Edit: corrected interchange type

Great work as always! I loved seeing the in-game comparison of these interchanges that are so common in southern Ontario! Two things on the AB4: 1. In real life, the south intersection - if not both - would be signalized and traffic exiting to go northbound would likely not turn into that leftmost lane, eliminating the northbound weaving. Southbound weaving does remain an issue though. 2. In the same way that an A4 prioritizes traffic exiting the highway and B4 prioritizes traffic entering the highway, AB4 prioritizes traffic heading to and from the east, since all movements to and from that direction are via free-flow ramps. That's why that design might be used in real life, for example, at a suburban interchange where most traffic is headed to and from downtown.

0:41 that is what i would call a modified cloverleaf, because the highway splits into 2 roads. one goes straight through while all the splitting, merging and weaving happens on the other one. but you can't really compare this one with the other ones in this video because they don't have the same types of roads. you can practically eliminate the weaving problem in a modified cloverleaf by switching the 2 lanes going into the side roads, using bridges. that way, the only weaving will occur when someone wants to do a 180 and go back the way they came. i built and tested one of them on the junction test map. i placed obstructions at thee exits from the cloverleaf, when it was all jammed up, i removed the obstructions and traffic flow was back to normal within minutes. the same test on the vanilla cloverleaf (not modified at all) and it did not recover. the cars kept blocking each other. BTW, i just noticed that some of the chevrons point the wrong way. they should be pointing where the traffic is coming from.

I love these comparison videos, super informative. Great format

The interchange I go through on my way to work has only a single B leaf, with the other side being a diamond. That's a lot of fun.

I've driven on what I'd think is a Parclo in Tennessee that was effectively an AB4, except both loops were on one side of the interchange. It had an arterial over the interstate with loops and slips on the southeast side of the interchange, or to your right if you were northbound on the highway. The opposite side just had ramps for on and off traffic. The leaves feed into a merge lane that comes off the main northbound lane and then re-merges after the northbound slip. Don't know how you'd classify it, but I'd say it worked, except for the fact that it was barely a mile up from a Flyover T that merged into I-40.

The AB4 can be the best option if most traffic from the aterial goes onto the same direction of the highway. This way it the biggest part of the traffic has only one traffic light at maximum insteat of two.

Why did no one think "a = after" "b = before" lol

One of my old friends used to live in a very rural area where the highway access was an AB2. They show up around here in rural areas and I imagine there are two reasons. 1) They take up less space and are probably better than a diamond. 2) They are probably logistically easier than either A2 or B2 because everything happens on the same side of the service road (east/west or north/south).

In my area, I have an A4 parclo, which has been designed to allow cars to pass through to get back on the freeway. I don't know why NCDOT does this. Probably to account for the people who have no idea where they're going. It flows decently enough, but its in need of traffic lights now that more industrial units are going up. I also have a more unique Parclo that's just a single leaf getting on the freeway while the rest of the interchange is a diamond. Don't know what to call that. But considering the area is mostly rural, it makes sense, with one direction meant to handle heavier traffic.

"A" means the loops happen Before the ramps, and "B" means the loops happen After the ramps. Amazing!

The B4 parclo with slip lanes is by far my favorite! Love this video 👍

I'm curious to see a comparison of other types of interchanges, including the diverging diamond. The one I'm most familiar with is in West Chester, OH, off I-75.

I find that roundabout parclo disfavors the crossing arterial thru traffic. It always backs up in configs like that

2:28 loved that giggle! 😂 Great video as always

In the Netherlands, I think AB2 parclos are functional because the right-turns seem to not have a free turn or slip lane. And since there's no right-turn on red, they have to wait for the light cycle like everyone else. And so that helps eliminates the weaving issue since the traffic getting onto the arterial bridge from the ramps aren't having to also negotiate with cars going straight through the arterial, since those cars get their own light cycle to enter the bridge.

There's an AB2 parclo on the edge of town here and it works just fine. I _think_ the reason it was picked was to fit in better with the surrounding urban developments though I'm honestly not entirely sure. It handles the flow of traffic fine in either case. Actually, the AB2 parclo seems to be a really quite popular service interchange around here. It's not just my town that's serviced by it (though it also has a B2 parclo), there are 4 other nearby towns that also have at least one AB2 serving them. They're more common than B2 parclos are. I honestly think the reason is just "space". All the room the interchange requires is just on one side, so it's just easier to fit in.

the Netherlands loves the partial cloverleaf (AB2). as most highway exits to towns use them. unless there is not enough space. however the weaving is mosly solved with Lane management before the all of the trafficlights. as here even collector roads are often 1 or 2 lanes unless your approaching a traffic lights. +for straight through traffic the 2 traffic lights if needed will be timed to allow perfect a perfect flow once the there a go on the 1st light.

I went searching for AB2 junctions in Massachusetts on Google Maps, and was not disappointed. It took all of 10 seconds to find one on I495. They really are terrible to drive on. The 495 to 2A interchange in Littleton is an example

I live in an area where the AB2 is being used. The primary reason being that there simply wasn't space for any other type of service interchange. The weave is solved, however, by making the arterial road only a two-lane road.

We used to have cloverleaf in this metro area but they were nearly all replaced by A4. Also we do have several AB4 interchanges as well.. yeah they really don't work well sometimes..

the roundabout parclos look great for irl (like if you take the wrong slip lane and wanted a left instead of a right, or if you missed a previous highway exit and need to turn around). think they're my favourite service interchange. not sure what my fave system interchange is (stacks are great but huuggee) - it'd be interesting to see a systems interchange comparison

The interchanges in my local area used to be all cloverleaf, all the time. Terrifying to deal with a car merging from the right in the weaves, and commuter traffic was just awful for that reason. They're converting to A4 parclos, which is better, though I personally think a DDI might've been a better use of the land area since they're expanding the overpasses anyway. There are intersections right up next to the overpasses, which is just indicative of letting the roads stagnate until there's a major traffic issue.

Yumbles B4 interchange made my first 100k population city possible after many failed attempts. The art of turning left

The B4 with roundabouts can be made in such a way that traffic exiting the highway still doesn't have to yield if you change the lanes on the roundabout, so that would still be an advantage over an A4

Love your video style man, keep it up!

Here's a metric I came up with to compare: 1) For lighted intersections, how many left turns a vehicle needs to take to get out of the intersection. Keep in mind one vehicle making a left turn will also block other vehicles, so less is better. 2) For roundabout intersections, how many other oncoming roads a vehicle needs to pass to get out, i.e. how much time does it spend in the roundabout. Again, keep in mind that a vehicle in the roundabout means some other vehicle has to stop and yield, thus creating more congestion. You should be able to count this up for each on-off direction, and see which ones are favored over others, which ones have the easiest/hardest time getting through. You should also be able to add them all up to get an overall idea of the effectiveness of an intersection; maybe add weaving points too if you want to do this.

My hometown had an AB2 as its main service interchange - and it's a tourist trap so traffic was always AWFUL. I think they went with it because most of our highways had to be blasted out of limestone mountains and bluffs, and it let the whole interchange be on one side of the road. At least learning to drive there taught me patience XD

While being a big traffic generator the AB2 still has its uses. There’s a couple in my city. They can be used if there is a light traffic road parallel to a river, railway track, etc, then there would be just one bridge on the highway going over the railway/river and arterial and it could all fit on one side of the highway since it would be quite difficult to have slip lanes on the other side and still have a short bridge.

*builds only AB interchanges and Cloverleaf interchanges just to watch Yumble pull out his hair in absolute frustration*

I notice that the B4 can be made into something contention free in about the same footprint as this by having the arterial left turns take the same exit as the arterial right turns, and adding grade separated ramps that run quasi-parallel to the highway, bridging from a (contraflow) access ramp lane, over half the highway, and becoming a left entrance. (Did I explain that clearly? The newly added bridges are one lane wide and go diagonally from where the main span passes above the ramp to the node where the traffic enters the highway.) There's a tradeoff in that the junction can be more compact if you use a tunnel, but the bridge is probably safer for a left entering (or indeed exiting) lane, since gravity is now on your side. It also precludes the more compact design where there are two separate highway exits and no protracted parallel ramp, I guess, unless you do some very fancy tunnelling. (I have no idea how well these could be implemented in the game, though.)

My favor is A4 instead of B4 for non-gameplay reasons. If the traffic exiting highway want to turn left onto another road after entering the arterial, the traffic lights can ensure the traffic make wide right turns, enter the innermost lane of arterial, and wait to turn left at next intersection. The B4 goes too smooth that they may have hard time changing lanes on the arterial. Side note for AB2: possibly because of railway, river, or something blocking on the no-clover side

Parclo junctions are now my standard service intersection once my diamond and elevated roundabout fail. They are rare in the uk which is why I avoid using them as they jar with my style.

Interesting thing about the roundabout one is that it is actually just the one roundabout, though it isn't really round anymore. We have them quite a lot in the UK, though usually when the arterial goes under the motorway (highway). The AB4 isn't as quite as bad as you suggest in reality, because traffic lights can manage the weave just fine, and traffic flow is not quite as regular as in cities skylines (not got after dark, does that change much?). For example, with lights WN traffic will go straight into the right lane at the junction, so shouldn't actually weave at all. You might use this junction where there is a significant bias in terms of highway direction. Traffic coming and going onto to the arterial from the east could be significantly higher than traffic from the west, especially at peak times. Think a commuter artery meeting an interstate, with nothing one direction for a significant distance. Rush hour traffic is going to be primarily one direction along the highway. Imagine if you were to get rid of the slip roads leading west entirely. Then you don't even need lights, there are almost no conflicts at all. The only issue left is that NE traffic has to weave through ES traffic, but NE traffic will be heavy in morning rush hour, while ES traffic will be heavy in the evening. The AB4 can be efficient at either getting cars onto or off the highway in a particular direction, and all you need to do to switch between them is change the light's timings. For a junction to handle rush hour commuter traffic this is a realistic requirement.

Hrm...I wonder how well an AB2 or AB4 interchange would work if two continuous flow intersections were introduced at the arterial...Now I remember - I actually did that, once, and then raised that turning left lane off the highway off-ramps into a low interchange (left turning lane bridged over straight through traffic) and it was glorious over-engineered madness. And it worked! And the AB2 interchange was necessary in that spot due to a river preventing a proper partial cloverleaf or even diamond interchange. IRL it would be an expensive boondoggle.

The AB2 wouldn't have a weaving problem in my country in Europe. According to local traffic laws it is allowed to pick any lane after a turn. So cars just go directly into the correct lane and there's no need to weave later. It would be better with a traffic light since picking lanes while making a turn means two cars cannot enter the intersection from a different direction at the same time without a collision. So it's important to give way and go only if all lanes on the priority road are empty.

Weaving is generally not an issue on the arterial, because the ramp terminals would usually have signals. Then traffic exiting the highway doesn't go at the same time as traffic entering.

In my town, AB2 is used. But it's different from yours. The reason is the presence of a canal. The arterial runs along the canal, the highway crosses above it. The leaves begin splitting off of the highway only after the crossing of the canal, so the bridge doesn't have to be broad. In fact there's even a second AB2 only 300m next to it for another 2x2 road crossing the canal and joining another arterial on the other side of the canal/railroad bundle, so that AB2 is 180 degrees turned. In the next city, there are 2 more AB2s, they are well used in my area. The reason there is for one the presence of a highway interchange just before the exit, and for the other one, it is the presence of an airport runway (the exit is right after the highway runs in a tunnel under the runway). There's also an AB4 in the area, with houses and other roads and interchanges nearby as reason.

I like the way you explain stuff. Please keep on.

To be nitpicky, the version with roundabout DO have yields. The roundabout has yield for cars entering :) The roundabout (or two half / one half and one full (depending on how the roads enter) roundabout is the most common in Sweden I think.

The AB variants would totally be worthy for regions where you already have built infrastructure around it and can't afford to demolish it AND if there is a lot more traffic on one side of the roads. When we see roads with 3+1 or 5+2 lane pattern, for example, looks like great spots for an AB, since the traffic on the side with more lanes should def be prioritazed

Never really liked full cloverleaf interchanges because of the weaving. I would prefer a stack to that from a traffic safety point of view. Even if they're fugly

There is actually an AB2 interchange along one of the main intercity highways in my city, BUT the reason for it is that because of how steep the grade is at the interchange point there is no other option but the AB2 on the side where the highway levels out.

I went on a journey in google maps to see the interchanges that are closest to me. A lot of half diamond, half parclo. North to south is with diamond, and south the north parclo, some even had sliplanes. Seems that the upgrade to the highway has added some sliplanes on parclo's. Few AB2, one in very small space, and other doesn't seem that busy area.

You should do a B4 roundabout combined with the overpass roundabout mod you made a vid about. You know, the overpass bypass roundabout.

AB4 is used when you have a lot of people getting onto the highway to drive east and a lot of people coming from the east who want to leave the highway. This is more of a real world scenario when you have morning and eventing rush hour traffic heading to and from downtown, something not seen in city skylines.

AB2 and AB4 just seem worse than a simple diamond service interchange in almost every conceivable way

3:44 Perfect ! I use this intersection without traffic lights.. only priority concession (TMPE) It is so realistic.

We are getting a new B2 parclo replacing a traffic light on a divided highway. The vast majority of the traffic is left turning at the intersection and there is a better route both ways further down the highway to do the right turning movement. Also, the terrain is not great for the slip lanes and it would require a lot more grading to make it work.

The AB2 parclo is verry common with roundabouts in the Netherlands especially on the N18

B4 w/ roundabout would seem to work better if you bypassed the roundabout on the A ramp forcing all left turns to use the B ramp. Would keep right turning and left turning traffic flowing really good

on the clover leaf, if the entry to the 2nd highway goes under or over the 2nd highway then joins from other side of the road that the leaving ram in front is on. so the weave is elimnated

Wow now wonder my hometown Frederick Maryland, got rid of the AB2 interchange of I-70 and south market street and built a new SPUI interchange right behind it all because the AB-2 was the worst of the worst!

Id like to see a high high cross where right turnering trafik separates first, the then right lanes bridges over left lanes making it inverted, the left turning trafik separates. The high ways crosses over under. Then left turning trafik joins from left, then the inverted lanes are reversed by a brigde and lastly the right turnering trafik joins . I Think it could make a compact desigh, without weaving and without clovers.

Video: by Yumbl me: Okay time for a game, take a shot whenever he says either 'Traffic Manager', 'Node controller', 'Junction' or 'Interchange'. Also me: nah, I dont want alcohol poisoning.

Interestingly, AB2 parclos are common in the Netherlands, along with A2 and B2 parclos. However, they also have a lot of diamond interchanges and parclo-diamond hybrids.

I use an AB2 if you are close to another interchange so you can try to make distance. Like I will often use them near stack interchanges.

No SPPARCLO? I thought it would make the list as it reduces points of conflict. Nice video though! I always wondered what the A's and B's, 2's and 4's were about. I might just use a standard A4 or B4 to replace a *very* substandard vanilla cloverleaf in my city.

I know everyone here hates the cloverleaf but hear me out. What if I tell you the weaving can be eliminated? The first step is already completed if you look at the start of the video - separating straight through traffic physically. Now what I propose next might seem unconventional. Lets reduce the speed limit on the on-off ramp to 50 km/h. And then put a yield sign before the cloverleaf circles. That way traffic coming off the circles gets priority. Traffic going straight has a perfect vision on the circles so they are in good position to safely stop and give way. Additionally this also makes the cloverleaf immune to gridlocks. Niw we're only left with one hazard - inattentive drivers who drive with closed eyes causing a rear end collision. This kind of people shouldn't be allowed behind the wheel anyway.

I Think The AB2 Is mostly Used for Two lane arterials connecting to a motorway or with Trafficlights to Prevent weaving.

8:50 i would think another advantage to the AB2 is if there is another interchange near it and there wouldn’t be enough room for a diamond interchange

In my opinion, an AB2 would be useful if you had an arterial where a majority of the traffic wants to go one direction (for example in your video, the leafs are on the western side of the arterial, all through traffic going north would not have to stop at any traffic light/intersection since there is no t junction going against northern flow). An A or B parclo wouldn’t work since there’s at least one t junction that goes against the arterial on both directions.

you forgot the 3s and the 5s, the break of symmetry is the beauty there (also there is the optimisation for traffic)

The A4 appears to be the preferred interchange, when there is room, here in Orange County, CA. Take a look at most of the service interchanges on I-5 @ i-405 from Irvine south to Mission Viejo. I think they're great, and love not needing to wait to turn left to get on the freeway. We have a couple real life AB2s here too. I-5 @ Tustin Ranch Rd in Tustin; I-405 @ MacArthur Blvd near John Wayne Airport; MacArthur Blvd @ University Dr in Irvine; SR-73 @ Bonita Canyon in Newport Beach / Irvine. I'm sure there are others, but these are the ones I use somewhat regularly. All have location constraints that make the AB2 the best option.

The AB2 could be useful if you have a place where on the arterial one direction of it is a lot more used than the other direction of it. So that direction always only turns right to enter the highway, and the other direction which barely has any traffic can give way to oncoming traffic

my preference is for a4 over b4, as realistically traffic getting off a freeway should not be favored to merge into neighborhood stretts at 50 mph. on the other hand, favoring the entrances means the motorist gets plenty of room to accelerate up to speed instead of having to stop first. also, realistically the ab2 and ab4 are used a lot right before a freeway crosses a bridge (usually over a body of water or under a railroad).

One could extend the B4 with roundabouts using the dedicated output lane system of a (hyper) turbo roundabout. It would have 4 outputs and 6 inputs. Future video maybe? ;)

hello, do you have any tutorials on highway exits? i usually just use roundabouts and steam assets like the the blackwidow ones.. also train interchanges if you might be interested. big fan here! after a long day at the hospital, i always look forward to playing and watching your tutorials

The ab4 sucks, but it’s also the real life single highest bandwidth example of a single bridge- parclo. Look up the ab4 single point parclo in fargo. It’s actually between a spui and your single point parclo in terms of flow. I’ve heard it be called a super spui. It uses a light phase with both quadrants hitting the same point just like an ab4 (inner leaf only) jug handle intersection to eliminate weaving. It’s hard to explain but give it a google. It’s my favorite interchange right now because it’s more applicable than a spui, ddi, a or b parclo for diamond interchange upgrades considering the dimensions, and also allows for a free- flowing highway runaround. Oh yeah, and no stop for straight through traffic on the “inner” side of the interchange. Smallest ramp length to interchange ratio I can find on a solid flowing interchange, so in game that translates to more interchanges on the same highway, longer weave zones for traffic volume compression space to keep my highways

Where I see the AB2 in real life, they have traffic lights on both sides of the highway synchronized to eliminate the weave.

Wow always love your incredible contents! A4 is always my favorite.

They just replaced a B2 with a diverging diamond near me and it's so much better and uses less space too.

you can go full cloverleaf and eliminate weaving by having a separate lane for the on and off ramps, so people join the lane before the onramp then they can exit, then the onramp traffic stays in that lane until after the offramp leaves it then they merge. So they are forced to both occupy the same lane and not cross each other.

Not to pull a Biffa with your B4 Roundabout Parclo, but the slip lanes that enter the roundabout and immediately exit (the slip lane that enters from the east and exits north and the slip lane that enters from the west and exits south), there's no reason the roundabout wouldn't be three lanes with the roads to the extreme north and south being 3+2 asymmetrical, and a few good reasons for why they would be. From a safety standpoint this allows cars to exit the highway and not merge at the roundabout where they basically have to be looking behind them to see traffic which may lead to feet leaving the brake pedal as they try to get their head and body turned around far enough which is very bad. Instead the merging happens after leaving the roundabout when the road is all nice and straight. This means no stopped traffic, which is good, and people being able to use their mirrors instead of craning their heads all of the way around, which is also good. Both those mean fewer accidents (of which the remaining are not the fatal kind), which is even better.

Well you can always use service oneway roads along a highway and 2-way ramps to get traffic on and off the service road from/to an arterial with dedicated lanes and lane math, no lights, no yields and much more compact than any type of cloverleaf or roundabouts.

Great vídeo. What happened if you change a B4 plus rounabout for b4 plus vanilla overpass road. Maybe it help left turns and straight in main road.

A2 and B2 (and probably AB) can definitely work with traffic lights if there's that much traffic.

I just love the B4.

Every variant you call the worst I instantly recognize from somewhere on the ring road of my home city of Edmonton XD

I'm from Canada and we got parcos everywhere

Imagine if City Skylines (2?) had inattentive drivers, and collisions because of it. The CHAOS caused by weaves would be so much worse.

In my city they just deleted one of the leaves and replaced it with a slip lane onto the highway the leaf would have connected to thus eliminating one of the weaves..

How about the "JVC Highway to 6 lane urban." It seems to work great.

Worst clover leaf style interchange I've ever seen is going south on GW parkway and trying to get on to 395 to go into DC... so much weaving causes so much traffic backup.

8:28 For parclo RA, I would give the roundabouts and the bridge 3 lanes minimum. You mentioned weaves, but lane math for roads that enter the city would be problematic if the merging keeps stacking and adding more to the existing traffic. Edit: I tried this on three cities since your last parclo roundabout video. Needless to say, TM:PE mod is involved.

It seems the major benefits to (partial) cloverleaves is only having two levels. The ideal interchange imo has 4 levels, I think I'll revisit the 4 stack interchange video. Do they cost more money or space and are they indeed better? Are there any hybrids of a partial cloverleaf with some third or fourth level to deal with left turns that don't lead to weaving or yielding/lights?

How do these ParClos stand against your almighty Single-Point version though?! I watched the entire video and was kind of expecting you to save it to last, but alas, no SPPC... On that subject, Ive tried the B4(with and without RA) and SPPC versions, and the only thing I dislike about the SPPC is the fact there is usually only one lane for crossing the overpass due to only 4 lanes available in total. In theory you could use a 6-lane road as overpass, but then the lane mathematics says you need a 8-lane road moving into the entire thing. What do you think about SPPC vs the B4 with or without roundabouts?

thanks - very interesting video 😁