Housing affordability = the cost to rent or buy, right?  But when if the cheapest housing is far away from where you work, urban centers, and essential goods and services?  Then, there's less of a chance that public transportation (transit) will be available or affordable, and if you drive, you'll drive farther and that'll cost more.

 So, the housing affordability consideration should include transportation costs, then, shouldn't it.  That's what the Center for Neighborhood Technology has done with their Housing + Affordability Index for 52 metropolitan areas in the US.

This is an example we need to remember in Humboldt County's General Plan when planners talk about affordable housing.