Palo Alto's Comprehensive Plan was guided by a philosophy called The New Urbanism. Hallmarks of this approach were recognizing what caused the suburbs developed in the 1950's and 1960's to be regarded as so "sterile," and recommending (sub)urban design practices that helped build community.
Reference: City of Palo Alto - Zoning Ordinance Update - New Urbanism Discussion Paper - references to additional articles/papers at end of this document