No. You can not alter neighborhood terrains already in use (i.e. lots already placed in the neighborhood). You can only create or edit blank terrains.

You can take an empty terrain from The Sims 2 and then alter it with SimCity4. You put that particular file here:

C:\Documents and Settings\YOU\My Documents\SimCity 4\Regions\Downloads\

(source: http://www.modthesims2.com/showthread.php?t=72813)

THEN when you're ready to put the terrain back into The Sims 2, then you can follow this FAQ: http://www.modthesims2.com/showthread.php?t=62258



Keywords: neighbourhood, terrain, change, road, sc4