Depends on the cities... here in the Phoenix area most of the buildings are only 1-2 stories.. and most of the larger parking lots don't get any shade from the buildings... There are several of these covered lots here in Phoenix, and more going up. A lot of places have covered parking anyway, so throwing solar panels on them isn't that much more cost in labor, and payoff in 8-12 years usually, with some profites for 5-15 after (at least from the costs of the past decade as a forcast).