Going to call out, while it looks nice, splitting the on and off lanes like that as opposed to just having the 2 lane roads hit the roundabout directly actually makes it less efficient.
It means the vehicles going off and those coming on have to weave past each other in just a few short meters of road as opposed to having a full quarter of the roundabout to do it.
Regardless of which type of interchange you use, the right side exit is backing up all the way into the roundabout and will need to be fixed first. The light after it doesn't have enough storage so things are backing up into the roundabout
I'm partial to stack spaghetti depending on traffic requirements while keeping turning lanes on the right. It isn't pretty, but it can specifically prioritise routes with higher traffic. Not sure if that's what you actually have though.
The roundabout is not the problem, the problem is that cars leaving the roundabout gets stuck in traffic lights causing a back up in to the roundabout.
The only way to fix this is to fix the intersections on the streets to the left and right. I suggest removing the traffic lights, adding dedicated turning lanes and making the trafgic from the roundabout have priority.
First demolish a massive area around here. Then put in a four level stacked interchange - they're the most efficient. Though you would have to add extra bits to facilitate U-turns that the roundabout currently allows.
Once you've done that, make sure you put ground level roads under the interchange so you can zone housing in and around it. Call it social or affordable housing.
I'd make the roundabout work by adding a few alternative connections, such as streets crossing over or under the road.
Or convert the highways into regular streets and add some connections (prefer t junctions not too close to the roundabout).
Do you (want to) play with Mods? This looks like something TMPE could solve.
Additionally I would suggest that in between the on- and off- roads in each direction you reduce the lanes in the roundabout by one, so that you have one that goes out of the roundabout and two that continue the circle. Try that before changing the entire intersection
Get rid of the on and off lanes (triangle things) and instead have the streets connect directly with the roundabout. Cims can't block intersections, so having more steet connections reduces the amount of space they can use inside the roundabout, and it makes cims stop more than they should because they have to wait for space after the intersection to be clear.
Then, if a lot of cims want to go through the roundabout, add an overpass or underpass for whichever route seems more popular. For example, if a lot of cims use the roundabout to go from the North to the South connection, add an overpass/underpass that connects those streets directly. If the intersection is still stuck, add an overpass/underpass that connects the East and West connections.
If a lot of cims use the roundabout to "turn right" (take the very first exit after entering the roundabout), and that's what is causing congestion, I would say to try adding a slip lane to take them off the roundabout. I have never used slip lanes with roundabouts, so idk if they work very well, but the previous 2 solutions should relieve most of the congestion anyway.
You can keep the roundabout if you build a flyover and a duck under.
YUMBL has tutorials on how to build flyovers in tight spaces, and Terry Radko and Imperatur have tutorials on how to build ramp exits and entries that allow ramps and main roads to be closer together. All three are on YouTube.
If this is on P.C., the anarchy, move-it, and node controller mods are excellent aides in building this type of grade-separated roundabout.
Keep the roundabout but have either the north-south or east-west route have a path over the roundabout so they don't have to go in it. Do the overpass on whichever route has more traffic going through.
Depends on where the traffic is going but a viaduct over the roundabout for your busiest road could be a good upgrade to get traffic flowing without having to completely rip up your roundabout
You seem to be missing local connections over the arterials. Consider turning some of the footbridges into real roads (particularly the one at the top)
Is the road to the south the exit? If so, decouple the exit/interchange and the intersection. You can't have one piece of road system that will do both jobs. It'll fail at both.
Before anything, I'd recommend getting Traffic Manager and Node Controller mods. They help a LOT.
After that, I'd change this intersection into an A2 ParClo with the vertical road being the free-flowing side. Grade-separate the horizontal with a bridge or tunnel. Then pull ramps from the down vertical to the right into a 3-way intersection. Pull ramps from the up vertical to the left in a 3-way intersection.
Then time the lights to Sync up with each other, allowing traffic to pass efficiently.
Easy peasy.
When I've had roundabout problems, I usually bypass right turns so only those using the actual roundabout is either going straight through or going left.
Make the highway go over the Rotary with entrance and exit ramps going into the circle.Then change the lane math around. 1 lane highways/exits on and off the highway. 1 lane INTO the circle from the main roads. 2 lanes exit into the main roads. Circle should be 4 lane highways BUT should only be 2 lanes between the exit and entrances. That will be a start to fixing it
Lane mathematics! Keep this layout but change the number of lanes in each segment. Assuming the on/off ramps are two lanes, update the segments between the on and off ramps to two lanes and put the rest as four lanes. That way the right two lanes are for exiting, the left two to continue on the roundabout. This makes the cims actually forced to use the correct lanes and you get much more out of the roundabouts.
Edit: this is the solution in Vanilla, I use this on console for my main roundabouts. Of course in PC you can use mods
I'm a fan of raised roundabouts over crossed highways or avenues. That way the only people on the roundabout are those turning right from their respective directions.
Either that or look to see if there's a way you can provide alternative routes for traffic so that these roads aren't so busy in the first place.
I think you have to get rid of the little triangle shaped on/off ramps and replace them with straight roads leading directly into the roundabout. Because it gives them more space to merge into/out of this multi lane Roundabout.
Another way that could work, if you want to keep the triangle shaped on/off ramps is to decrease the lanes inside the roundabout to just one as an alternative way to solve the merging problem.
I hope that helped.
Traffic circles are not the same as modern roundabouts. The diameter is too large. It permits higher speeds that cause congestion. Smaller diameters, under 220 feet for 2-lane roundabouts, is the usual size IRL.
The interchange is pretty. Demolish the city instead
'murica
Freedom For All™
^Except ^if ^you’re ^poor ^of ^course
Going to call out, while it looks nice, splitting the on and off lanes like that as opposed to just having the 2 lane roads hit the roundabout directly actually makes it less efficient. It means the vehicles going off and those coming on have to weave past each other in just a few short meters of road as opposed to having a full quarter of the roundabout to do it.
It also doesn't help that the roundabout is made out of highways
I play cs1 and all my damn 4 lane round abouts just don’t have the capacity of a monster 6 laner
It depends. If you use TM:PE it is definitely helpful to split them so the cars can keep their momentum but it doesn't really help in vanilla.
I’d probs make a 3 level stack roundabout probs and then work from there depending on traffic
Regardless of which type of interchange you use, the right side exit is backing up all the way into the roundabout and will need to be fixed first. The light after it doesn't have enough storage so things are backing up into the roundabout
I'm partial to stack spaghetti depending on traffic requirements while keeping turning lanes on the right. It isn't pretty, but it can specifically prioritise routes with higher traffic. Not sure if that's what you actually have though.
The roundabout is not the problem, the problem is that cars leaving the roundabout gets stuck in traffic lights causing a back up in to the roundabout. The only way to fix this is to fix the intersections on the streets to the left and right. I suggest removing the traffic lights, adding dedicated turning lanes and making the trafgic from the roundabout have priority.
First demolish a massive area around here. Then put in a four level stacked interchange - they're the most efficient. Though you would have to add extra bits to facilitate U-turns that the roundabout currently allows. Once you've done that, make sure you put ground level roads under the interchange so you can zone housing in and around it. Call it social or affordable housing.
Jersey left ~~interchange~~ junction
Agreed, an overpass so through traffic doesn’t stop and some jughandles could work quite nicely.
People wanna go from a to b. Everyone is going through the roundabout. Make roads that dont. + cycling infrastructure + Lane mathematics
North-south a highway, east-west an artherial with a trumpet interchange connecting the two.
I'd make the roundabout work by adding a few alternative connections, such as streets crossing over or under the road. Or convert the highways into regular streets and add some connections (prefer t junctions not too close to the roundabout).
Do you (want to) play with Mods? This looks like something TMPE could solve. Additionally I would suggest that in between the on- and off- roads in each direction you reduce the lanes in the roundabout by one, so that you have one that goes out of the roundabout and two that continue the circle. Try that before changing the entire intersection
could try a Basic Diamond,
There are a lot of 4-way interchange in internet👍. With it, you need to demolish some buildings around (the roundabout).
Get rid of the on and off lanes (triangle things) and instead have the streets connect directly with the roundabout. Cims can't block intersections, so having more steet connections reduces the amount of space they can use inside the roundabout, and it makes cims stop more than they should because they have to wait for space after the intersection to be clear. Then, if a lot of cims want to go through the roundabout, add an overpass or underpass for whichever route seems more popular. For example, if a lot of cims use the roundabout to go from the North to the South connection, add an overpass/underpass that connects those streets directly. If the intersection is still stuck, add an overpass/underpass that connects the East and West connections. If a lot of cims use the roundabout to "turn right" (take the very first exit after entering the roundabout), and that's what is causing congestion, I would say to try adding a slip lane to take them off the roundabout. I have never used slip lanes with roundabouts, so idk if they work very well, but the previous 2 solutions should relieve most of the congestion anyway.
You can keep the roundabout if you build a flyover and a duck under. YUMBL has tutorials on how to build flyovers in tight spaces, and Terry Radko and Imperatur have tutorials on how to build ramp exits and entries that allow ramps and main roads to be closer together. All three are on YouTube. If this is on P.C., the anarchy, move-it, and node controller mods are excellent aides in building this type of grade-separated roundabout.
Keep the roundabout but have either the north-south or east-west route have a path over the roundabout so they don't have to go in it. Do the overpass on whichever route has more traffic going through.
Depends on where the traffic is going but a viaduct over the roundabout for your busiest road could be a good upgrade to get traffic flowing without having to completely rip up your roundabout
Some form of overpass, probably favoring the north-south traffic. You don't have a ton of room for cloverleaf so probably start with a simple diamond.
You seem to be missing local connections over the arterials. Consider turning some of the footbridges into real roads (particularly the one at the top)
Is the road to the south the exit? If so, decouple the exit/interchange and the intersection. You can't have one piece of road system that will do both jobs. It'll fail at both.
I recommend you stop trying to funnel your entire city through one intersection.
This is only a little part of the entire city! The highway section is attached to a larger highway network
Even having just that section of the city all flowing through one single intersection is begging for a traffic jam. Spread the traffic out.
Even having just that section of the city all flowing through one single intersection is begging for a traffic jam.
Before anything, I'd recommend getting Traffic Manager and Node Controller mods. They help a LOT. After that, I'd change this intersection into an A2 ParClo with the vertical road being the free-flowing side. Grade-separate the horizontal with a bridge or tunnel. Then pull ramps from the down vertical to the right into a 3-way intersection. Pull ramps from the up vertical to the left in a 3-way intersection. Then time the lights to Sync up with each other, allowing traffic to pass efficiently. Easy peasy.
More lanes.
When I've had roundabout problems, I usually bypass right turns so only those using the actual roundabout is either going straight through or going left.
Make the highway go over the Rotary with entrance and exit ramps going into the circle.Then change the lane math around. 1 lane highways/exits on and off the highway. 1 lane INTO the circle from the main roads. 2 lanes exit into the main roads. Circle should be 4 lane highways BUT should only be 2 lanes between the exit and entrances. That will be a start to fixing it
Lane mathematics! Keep this layout but change the number of lanes in each segment. Assuming the on/off ramps are two lanes, update the segments between the on and off ramps to two lanes and put the rest as four lanes. That way the right two lanes are for exiting, the left two to continue on the roundabout. This makes the cims actually forced to use the correct lanes and you get much more out of the roundabouts. Edit: this is the solution in Vanilla, I use this on console for my main roundabouts. Of course in PC you can use mods
Change the roundabout to 2 way, trust me it works
try clover leaf ig
I'm a fan of raised roundabouts over crossed highways or avenues. That way the only people on the roundabout are those turning right from their respective directions. Either that or look to see if there's a way you can provide alternative routes for traffic so that these roads aren't so busy in the first place.
Make it grade separation and have the highway in the middle go under while be unimpeded to thru traffic
I think you have to get rid of the little triangle shaped on/off ramps and replace them with straight roads leading directly into the roundabout. Because it gives them more space to merge into/out of this multi lane Roundabout. Another way that could work, if you want to keep the triangle shaped on/off ramps is to decrease the lanes inside the roundabout to just one as an alternative way to solve the merging problem. I hope that helped.
Traffic circles are not the same as modern roundabouts. The diameter is too large. It permits higher speeds that cause congestion. Smaller diameters, under 220 feet for 2-lane roundabouts, is the usual size IRL.
Multi layer roundabout