You can’t judge housing affordability without knowing transportation costs

They’ve used census data on income and housing costs, and estimates of commuting patterns, transit available and car ownership to estimate what fraction of a household’s income gets spent on housing and transportation in different locations. For example, households in the second quartile who spend less than 30 percent of their income on housing spend 12.6 percent of their income on transportation. Households that spend less than 30 percent of their income on housing in this group spend $2,300 per month on transportation.

Source: cityobservatory.org