Simpleton Series: Build an underpass in SimCity 3000

Contributor/author(s): Simpleton

In a road or rail or road/rail system, there are three ways of dealing with a crossing of thoroughfares.

• You just do it on the same level and leave Sims to get on with it
• You use the 'Tunnel Crossing' method
• You create an underpass.

The first one can give you traffic congestion problems. The second is space efficient, does the job, but looks unrealistic. The third is less space efficient but is both more visually pleasing and realistic. There are also a few other use angles to this latter one.

First thoughts are towards the straight thoroughfare crossing to alleviate congestion - out in the country where two highways cross. Thinking a bit further - underpasses can be in the central city and can be as long as you care to make them. They could stretch a couple of city blocks or more. You might, for example, have one (or several) dual carriageway avenues right under your city heart, surfacing here and there for access.

You then get the best of both worlds - you have dual carriageway access right into the middle of your city but have the city centre surface clear to build the density you wish without a visible dual carriageway taking up heaps of space.

The underpasses use space via their cutting embankments. The illustrations show the most visually attractive solution giving a 5 tile slope down to the tunnel. This can be reduced to 3 tiles each side of the tunnel and still be acceptable - depends how space hungry you are. In the 5 tile slope you are using 15 tiles each side of the road being underpassed for a single lane underpass. If you are putting a double lane underpass then you use 20 tiles each side!

On the other hand you need parks for inner city values so they could be placed beside the underpass cuttings which have been planted with trees - turning the combination into a landscaping feature. There are actually quite a few dimensions for an active imagination! Here is how to build a single and dual underpass.

Single lane underpass to a dual carriageway (this could be either road or rail)

1. First of all you need the terrain depth to do the excavating. You require 65 metres of depth from ground surface downwards without hitting water!
2. Select where you want the centre of the underpass to be. Put down a couple of road tiles on the axis of the underpass leaving 14 empty tiles between.
    
3. Use the 'Lower Terrain' tool - place the cursor a couple of tiles in from each of the road marker segments and give 4 clicks to lower the surface.
4. Use the 'Level Terrain' tool to give you 4 tiles of flat surface running along the axis of the intended underpass on both sides.
    
5. Run 3 tiles of road along the underpass axis up to the central bank and onto the first tile of the bank. Release the mouse button.
6. Accept the build tunnel invite.
    
7. Bulldoze the road entry tiles at each end of the tunnel including the marker tiles.

   Note: Keep a sense of proportion with the following, it is easy, but difficult to write easily. Keep a sense of objective on what you want to do - raise a gentle slope from the tunnel mouth to the surrounding terrain! Be careful you do not slip with the Terrain Level Tool and start extending the excavation from the 4 tile set-up!

8. Use the 'Raise Terrain' tool 1 click on the tile one removed from the tile you wish to slope! Now use the 'Level Terrain' Tool to level the remainder of the space within the excavation away from the tunnel mouth. Continue progressively working this way until you have an even slope to the surrounding terrain surface.
   

   Note that you will end up with one raised tile outside the excavation - trim this with the Level tool.

9. Build your underpass roads and crossing roads.

Dual lane underpass to a dual carriageway (this could be either road or rail)

Basically build as per directions given above, with these additions:

1. I strongly suggest you put in a few tiles of your dual carriageway which you intend to underpass.
2. Ensure you have left one tile clear each side of the dual carriageway.
3. Work outwards each side and dig your 4 tile excavation as per directions given above.
4. In Step #4 widen the trench 1 tile to accept the two lane underpass
5. Now here is the main change - use the 'Level Terrain' tool 1 tile sideways each side of the intended underpass entry to enable you to use the double tunnel method.
    
6. Run one line of road into the blocking face along the underpass axis and then up onto the first hill tile and release the mouse button. (see the former illustration)
7. Accept the 'build a tunnel' invite.
8. Run 4 tiles of road across the face of the tunnel entry you have created.
   

   Start from the tile in the picture where the '$0' marker is, across the tunnel, two more tiles and then up onto the face of the slope. The cursor will turn red but the tile beside the existing tunnel will turn blue.

9. Accept the 'build tunnel' invite. You now have a double tunnel!
10. Build the ramps in the same way as already given - just double up)
11. Bulldoze unwanted road tiles and use the 'Level Terrain' tool to tidy up unwanted excavations.
     
12. Build your underpass and crossing thoroughfare roads.
13. Landscape, or go from there, as you desire.

Inner city underpasses

Use either of the techniques given above - but you will probably be on dual carriageway. The only difference is how long you make the tunnels and where the underpasses surface and then dive down again. Your needs - your imagination!

Underpassing a river

There are a number of good reasons for doing this -

• You can have a lot of road connections between river sides without the clutter of a lot of bridges.
• You can have total use of high value waterfront land for building by setting the underpass entries as many tiles back from the river bank as you like
• The technique visually looks more realistic than the usual berm method - even though the berm method actually has to be used.

In the demonstration illustration below, the underpass has been set back both sides of the river bank to allow for continuous river front zoning. Note also that the 'beached bank' technique has been used on the 65 metre elevation terrain.

An assumption is made that you are only likely to want to bother with this for a dual carriageway but you could use a single lane underpass if you wish.

1. Arrange your terrain to be 65 metres above the river surface on both sides of the river
2. Use the 'Raise Terrain' & 'Level Terrain' tools to build a two tile wide berm across the river from bank to bank to the height of the surrounding terrain
3. Select where you want the underpass entries to be and follow the directions given above.
4. Once the tunnels are in place use the 'Lower Terrain' & 'Level Terrain' tools to lower the berm below water surface height.

See also
An alternative to regular intersections