Simpleton Series: Tunnel intersection crossing in SimCity 3000

Contributor/author(s): Simpleton

Objective: To reduce traffic congestion at road/road. road/rail, rail/rail cross points.

This technique uses the flat entry/exit level method with minimum space loss. The technique comes from 'Free Up Developable Land with Tunnels' by John McCrory and is refined slightly to ensure you have minimum hassles with slope steepness at the tunnel entry to avoid your tunnel climbing a bank or refusing to build. This will give you a space efficient 'flat entry' combined with the technique. You do not need to be on any particular terrain elevation, just flat for the area the cross over will use.

The effect given works, but does not look very realistic. Its main purpose is to reduce extreme traffic congestion in already built up areas with minimum destruction while you do it. The technique also uses maximum economy on tile usage - but is still expensive.

1. Decide what tiles you want your tunnel entrance and exit to be at. If you are crossing a single carriageway then you must have 5 clear tiles over the crossing. If you are crossing a double carriageway then you require 6 clear tiles.
2. In this demonstration I am crossing a dual carriageway with a single road.
   

   In the illustration above I have put in two portions of the dual carriageway for clarity. I have placed a single road tile as a 'forcer' tile 3 tiles from the dual carriageway centreline. A stretch of the single road is also shown to demonstrate the axis of the tunnel and I have commenced this from where the tunnel will exit.

3. Load the 'Raise Terrain' tool and move 2 tiles down the intended tunnel line. Now use the tool to raise the ground 4 clicks.
    
4. Use the 'Level Terrain' tool to give you a flat topped raised berm between entry and exit. Push the tool against the 'forcer tiles' until the cursor goes red. This will also ensure you have a steep slope and sharp edge at the bottom.
5. Return to the entry point and run a road/rail selection over your starting tile, across the blank tile, and onto the first tile of the slope. Release the mouse button.
    
6. Accept the 'Build Tunnel' invite.
7. Use the 'Level Terrain' tool to destroy all high ground other than what comes up red on the cursor pointer.
    
8. Build your road or rail tiles up to the tunnel entrances and then the carriageways you are crossing.
9. Decorate the remaining slopes with trees, or extend them and use them for other purposes.

Notes

• The effect is not visually very realistic but is space efficient, not too expensive, and works first time.
• You can use a double tunnel to create a crossing between two dual carriageways.
• Do not put two rail lines side by side as this will cause rail traffic problems - you will have to use single underpasses for each rail line.

See also
An alternative to regular intersections