Many suburban main streets are filled with a mix of one and two storey retail, and Wellington Street in Ottawa fits the pattern. It's pretty ugly. On the other hand, the formerly working-class Hintonburg area of Ottawa is on the upswing, "reborn as a magnet for chefs, artists, brewers (of both coffee and beer), innovative businesses — and people looking for a home in an authentic neighbourhood."
It is areas like this where low-rise buildings can add a lot of people without building monster towers. A great example is the Eddy, going onto the site of a garage and used car lot. Windmill Developments and Christopher Simmonds Architect have designed a really green and gorgeous six storey building that puts 57 residential units in the space of about that many cars.
It is going for LEED Platinum, with ground source heat pumps for heating and cooling, formaldehyde free low-VOC materials and a big, secure bike room. Units start surprisingly small, the smallest at 378 square feet.
It has a wild parking garage system called 5BY2 that shuffles the cars around like one of those sliding puzzles, that uses 60% less space and keeps vehicle emissions out of the building. Parking garages are often a safety concern, and this system solves that problem. Looks complicated though; I'd keep a bike in that big bike room for backup.
Here is a video of it in Dutch.
Just about everyone agrees that cities that are comfortable to walk and bike in are a greener way to live. Just about every city has miles and miles of Wellington Streets with convenience stores and car lots that could be intensified with low-rise buildings like this. Main street intensification has so many benefits, from supporting transit and local businesses to the safety that comes from eyes on the street. Often the problem has been the difficulty of building parking on such small sites; This project demonstrated that there can even be innovation there.