Make Avenue Roundabouts,I still haven't figured it out :'(
The NAM has a Avenue Roundabout lot puzzle piece. You can find it in the Road menu of the game.
Serkanner: make that puzzle piece ;)
when you install the NAM you must select the Avenue Roundabouts Plugin.
In the Road menu there should an icon of a roundabout click that and place it, then drag avenue from the sides.
Oops &ops ... I mean puzzle piece of course ... &ops
Also be sure that you have the LATEST version of the NAM (i.e. Jun/Jul 2007) and that you delete the middle four grass tiles after you placed the puzzle piece. ;D