I’m not yet familiar with BlueBrick so I’ve come up with a quick .jpg to show one basic option for connecting the side street to main roads. In the diagram, the scale is set to that the main road is 16 wide, but I don’t think it’s really essential for the lanes to match up that exactly, anybody who’s driven around the greater Pittsburgh area is familiar with the side street of random width.
Matching up a snot-brick road to a nonsnot-tile road might be more of a challenge, I figure the only way to sort it out is actually try it and see how it looks. If there’s a slight height discrepancy, there’s a multitude of options of dealing with it, including pieces like these two:
http://www.bricklink.com/catalogItem.asp?P=85984
http://www.bricklink.com/catalogItem.asp?P=4515
Also, it’s possible that as we get into 2014 and I expand my town layout, things can be rearranged and I can abandon the side street. For the time being though, I need to keep it.