Could it be that walkable areas are desirable and rare — and therefore have higher prices? Higher-priced homes have a lower rates of default, no? The question then becomes: are these walkable areas higher priced because they are walkable, or for some other reason?

And is downtown SD really walkable? Sure, the nightlife is walkable, but what about actually living there? How many parks are there in downtown? How many grocery stores? How many community gathering spaces?