This will work for roads. For this to work though, you must install the Network Add-on
mod (NAM). You can then drag out a one-way road and change it into a road with no 
intersection. Keep the one-way road a road for just one square and drag a road to cross
the one way road's single road section. For lights to be facing the correct ways, you 
can use the BAT (Building Architect Tool), the Plug-in Manager, and the Lot Editor to 
create intersections. However, you must also get the SC4 tool. 
Note: These tricks do not prevent cars from turning the wrong way.