Exclusionary zoning, practiced throughout most of the United States, is one of the most damaging forms of class discrimination.  There is a racial component to it in many suburbs, but it really falls on a strata of society which is generally less educated and less affluent.  Interestingly, liberal communities actually engage in the practice at higher rates than conservative ones.  Call it a new and more subtle form of bias against those who have achieved less financial success.  Its impact on educational outcomes, transportation problems and maintaining the yawning gap in income inequality in America is not well understood.  And while there are reasons for minimum lot sizes, such as septic systems requiring land for their leach fields, in many towns the truth is the detached home on a large plot concept is meant to enhance property values and exclude those not welcome in various communities.  In his book, “Excluded: How Snob Zoning, NIMBYism, and Class Bias Build the Walls We Don’t See,” Richard Kahlenberg does a great job of breaking down all of the issues at play as America maintains a legal, though harmful, form of discrimination.  You’ll want to listen in.