Compact Interchange Kit

The default answer for getting traffic on and off into a district. Handles a full neighborhood without lights, and the roundabouts self-balance turning traffic in a way CS2's AI is good at.

1. Run the city road over the highway at 8 to 10 m elevation, perpendicular, so a clean bridge forms with no junction node.
2. Place a small roundabout on the city road on each side of the bridge, about 60 to 80 m from the highway centerline. Use a prefab roundabout if you have one unlocked, or draw a ring with a two-lane one-way road, roughly 30 to 40 m across.
3. Off-ramps: from the right lane of each direction, before the bridge, run a one-lane ramp that climbs to the near roundabout. That is the bottom-left and top-right ramp in the plan.
4. On-ramps: from the same roundabout, run a ramp back down that merges after the bridge. Each roundabout ends up with four legs: bridge, city road, one off-ramp in, one on-ramp out.
5. Flat variant: if elevated roundabouts look wrong to you, trench the highway 8 to 10 m down instead and keep the city road and both roundabouts at ground level. Same layout, nicer skyline.

Same footprint as the dumbbell, minus the roundabouts: two signalized ramp terminals instead of two rings. Cheaper and faster to place, but the signals cap how much turning traffic it can absorb before queues start reaching the bridge.

1. Run the city road over the highway at 8 to 10 m elevation, same as the dumbbell, so a clean bridge forms with no junction node.
2. Mark two signal points on the city road, one on each side of the bridge, about 60 to 80 m from the highway centerline. These are the only two intersections in the whole build.
3. Off-ramps: from the right lane of each direction, before the bridge, run a one-lane ramp that climbs and merges into the near signal junction.
4. On-ramps: from the same junction, run a ramp back down that merges into the highway after the bridge. Each junction ends up with four legs: city road through both ways, one off-ramp in, one on-ramp out.
5. If queues back up onto the bridge, you have outgrown the diamond. Upgrade the busier junction to a roundabout (now it is a dumbbell) or add a second turn lane on the city road approach before touching the ramps.

Half diamond, half cloverleaf. Put the loops in the two quadrants where you actually have room and let the other two stay simple diagonal ramps. One signal instead of two, and it swallows more turning traffic than a plain diamond because the loop movements never touch the light.

1. Bridge the city road over the highway at 8 to 10 m, same as every other build here.
2. Build the two loops first, in whichever pair of adjacent quadrants actually has open land. About 35 to 45 m radius: one exits the highway and climbs to merge onto the city road, the other drops off the city road and merges onto the highway. Neither one ever touches a signal.
3. In the two remaining quadrants, run simple diagonal ramps from the highway to a single point on the city road, same as half of a diamond.
4. Put one signal where those two ramps meet the city road. That is the only traffic light in the build; the loop side never needs one.
5. Pick the loop side by land, not by traffic volume. If the heavier turning movement has to go through the signal, add a right-turn slip lane on the city road approach to keep it out of the queue.

All four ramps and the city road meet at one large signal instead of two small ones. Every left turn happens inside that single intersection at the same time, on its own phase, which is why an SPUI moves more turning traffic through less land than a diamond can.

1. Bridge the city road over the highway at 8 to 10 m, with a longer span than the other builds. The single point needs more room under it for the ramps to gather.
2. Bring all four ramps to one point directly under the bridge, two from the west side of the highway and two from the east, each pair fanning out to become the city road's through lanes on the far side of the signal.
3. Build the signal as one wide, one-lane intersection, not a cluster of smaller ones. CS2 will treat it as a single node if the ramps and city road all terminate close enough together.
4. Give the city road extra width approaching the signal so left-turn lanes have somewhere to queue without blocking the through lanes.
5. Use this over a diamond only when the city road is already busy. A single big signal is worse than two small ones on light traffic; it only wins once turning volume is high enough to need simultaneous phases.

The cloverleaf was invented for exactly this road type: two-way highways crossing. Every one of the twelve movements is free-flow, and it needs only one bridge, which makes it the easiest full interchange to build by hand in CS2.

1. Bridge one highway over the other at 8 to 10 m. That is the only elevation change in the whole build.
2. Four outer ramps for right turns: in each quadrant, exit the right lane before the bridge, sweep a wide curve around the outside of where the loop will go, and merge onto the other highway after its crossing point.
3. Four loop ramps for left turns: pass the bridge first, then exit right into a loop of about 35 to 45 m radius that comes all the way around and merges onto the other highway.
4. Sanity check each direction. Driving through, you should pass nodes in this order: off, on, bridge, off, on. If any pair is swapped, a ramp is on the wrong side of the bridge.
5. Mind the weave. The "on" before the bridge and the "off" after it share the right lane, so keep those two nodes as far apart as the loops allow. If that stretch ever jams late-game, add a short parallel collector ramp connecting loop entry straight to loop exit so weaving traffic never touches the mainline.

The cloverleaf's loops replaced with direct flyover ramps. No 270-degree turns, no weaving between the "on" and the "off" that share a lane on the cloverleaf, and every left turn takes the short way instead of the long way around. The cost is four separate ramp elevations instead of one bridge.

1. Bridge one highway over the other at 8 to 10 m, identical to the cloverleaf. This is level 2.
2. Four outer ramps for right turns, same geometry as the cloverleaf: exit before the bridge, curve around, merge after it. These stay close to ground level.
3. Four flyover ramps for left turns, each a short direct curve instead of a loop: exit after the bridge, climb, and merge onto the other highway before its crossing point.
4. Stagger the flyover elevations. Two of the four flyovers will cross paths in plan view; give one 16 m and the other 24 m so they pass over each other with clearance instead of colliding.
5. Only build this over a cloverleaf when the loops are the bottleneck. Flyovers move more traffic and remove the weave entirely, but four elevations cost more to grade and look like a plate of spaghetti from the ground. If the cloverleaf isn't jamming, it isn't worth the upgrade.

For a spur, a map-edge highway, or any two-way highway that terminates instead of crossing through. Four ramps cover all four movements: two simple ones on the near side, and two that cross the mainline on a single bridge to reach the far carriageway, one of them the loop.

1. End the terminating highway short of the mainline, about 100 to 140 m back. Everything past that point is ramps.
2. Near-side pair first: one ramp off the near carriageway down into the terminating highway, one back up out of it. Both stay at ground level and never cross anything. These are the cheap ones.
3. Far-side pair next: the other carriageway is on the wrong side of the mainline, so its two ramps have to climb. Take them over at 8 to 10 m, or trench the mainline and pass under. They will also cross the ground ramps and each other, so stagger their heights 6 to 8 m apart.
4. Keep every curve wide. Nothing tighter than a 35 to 45 m radius, and bring each ramp into the terminating highway pointing the same way it runs, not at an angle. A ramp that meets a road sideways is a ramp cims will not take.
5. Check all four movements before you leave. Drive on and off in both directions: if any one of the four cannot be done without a U-turn, a ramp is pointing the wrong way. This is the mistake that makes a trumpet look finished when it is only half built.

The smallest grade-separated interchange you can make. Through traffic on the highway never slows down; everything else yields on one elevated roundabout. Perfect early game, or where the crossing road is minor.

1. Leave the highway alone. It runs straight through at ground level and never gets a junction.
2. Draw a roundabout 8 to 10 m up, centered right on the crossing point, about 130 to 160 m across, using a two-lane one-way road. Bigger ring means faster circulation.
3. Connect the crossing road into the ring from both sides.
4. Run four one-lane ramps between highway and ring, one per quadrant: off-ramps climb in before the ring, on-ramps drop out after it, for each direction.
5. Trench variant: sink the highway instead and keep the ring at ground level; it hides the interchange almost completely.