郊区化(Suburbanization)

ifby"suburb"ismeantanurbanmarginthatgrowsmorerapidlythanitsalreadydevelopedinterior,theprocessofsuburbanizationbeganduringtheemergenceoftheindustrialcityinthesecondquarterofthenineteenthcentury.beforethatperiodthecitywasasmallhighlycompactclusterinwhichpeoplemovedaboutonfootandgoodswereconveyedbyhorseandcart.buttheearlyfactoriesbuiltinthe1840swerelocatedalongwaterwaysandnearrailheadsattheedgesofcities,andhousingwasneededforthethousandsofpeopledrawnbytheprospectofemployment.intime,thefactoriesweresurroundedbyproliferatingmilltownsofapartmentsandrowhousesthatabuttedtheolder,maincities.

asadefenseagainstthisencroachmentandtoenlargetheirtaxbases,thecitiesappropriatedtheirindustrialneighbors.in1854,forexample,thecityofphiladelphiaannexedmostofphiladelphiacounty.similarmunicipalmaneuverstookplaceinchicagoandinnewyork.indeed,mostgreatcitiesoftheunitedstatesachievedsuchstatusonlybyincorporatingthecommunitiesalongtheirborders.

withtheaccelerationofindustrialgrowthcameacuteurbancrowdingandaccompanyingsocialstress-conditionsthatbegantoapproachdisastrousproportionswhen,in1888,thefirstcommerciallysuccessfulelectrictractionlinewasdeveloped.withinafewyearsthehorse-drawntrolleyswereretiredandelectricstreetcarnetworkscrisscrossedandconnectedeverymajorurbanarea,fosteringawaveofsuburbanizationthattransformedthecompactindustrialcityintoadispersedmetropolis.thisfirstphaseofmass-scalesuburbanizationwasreinforcedbythesimultaneousemergenceoftheurbanmiddleclass,whosedesiresforhomeownershipinneighborhoodsfarfromtheaginginnercityweresatisfiedbythedevelopersofsingle-familyhousingtracts.