building mass rapid transport systems above ......29 june 2017 page 1 of 3 building mass rapid...
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29June2017page1of3BUILDINGMASSRAPIDTRANSPORTSYSTEMS
ABOVEGROUNDORBELOWGROUND?
1. Backgroundandintroduction
TheCityofBogotáinColombiaisconsideringanewmetrosystem.Thecurrentplansindicatethistobeanelevatedmetrothatrunsthroughthecity.ACTOShasaskedITACUStoindicatetheirthoughtsonthismatter.
ArtistimpressionoftheelevatedmetroinBogotá
2. ITAWorkingGroup13report
ITA1WorkingGroup13madeanextensiveinvestigationintotheargumentsforandagainstplacingametrobelowthesurface.Thereporthasbeenattachedandalthoughitwaswrittenin2003,manyoftheargumentsinthisreportstillholdtruetoday.Theargumentswillnotberepeatedhere,pleaserefertothereportforthis.
3. TheCitiesWeNeed
In2014theWorldUrbanForumwasheldinMedellin,Colombia.Theevent,organisedbyUNHabitatwasbasedonthequestionwherearewegoingwithourcities.FromthistheWorldUrbanCampaigndevelopedthe‘CitiesWeNeed’campaign.Twopointsinthiscontextarerelevantforpoliticaldecisionmakers,policymakersandurbanplanners:
1InternationalTunnellingandUndergroundSpaceAssociation,Lausanne,Switzerland
29June2017page2of3• Theurbandevelopmentdecisionswemaketodaywillbeseenacrossthefacesofourcityscapes
forgenerationstocome(posterattheWorldUrbanForumheldinMedellinin2014);• Thecitieswewantshouldbeenginesofeconomicdevelopmentandlieatthecoreofanew
urbanerawherepeoplecanfindfreedom,innovation,prosperity,andresilience(PublicationbytheWorldUrbanCampaignin2016inpreparationfortheHabitatIIIconference).
WorldUrbanCampaignposterattheWorldUrbanForuminMedellin,Colombia.
Itisthesetwopointthatshouldbecriticalwhenitcomestodecidingonwhethertobuildthemetroelevatedatthesurfaceorbelowthesurface.
Elevatedinfrastructurehasbeenusedincitiesallovertheworld.Allovertheworldwenowseethesestructuresbeingtakendown.Theydivideneighbourhoods,thepreventfurtherdevelopment,theylowerthevalueofrealestateinthevicinity.Indeed,citiessuchasBoston,MA,UnitedStates;RiodeJaneiro,RJ,Brazil;andMadrid,Spain;haveallplacetheirroadinfrastructurebelowthesurfacetofreeupsurfacespace.Valuablesurfacespacethatwasoftenredevelopedintogreenpublicspaces.Thereasonforthisisthatcitiesnotonlyfacethechallengetobeliveableandinclusivefortheircitizens,theyneedtobeclimateproofandresilientaswell.Greenpublicspacesprovidenaturalinfiltrationofrainwater,thetreesabsorbCO2andthegreeneryreducestheurbanheatislandeffect.Oneofthechallengeswehaveisthatastheclimateischanging,ourcitiesareheatingwhichiscausinghealthproblemsforthecitizens.Introducingnewconcretestructuresintothecityonlyraisesthiseffect.
29June2017page3of3Soapartfromallotherarguments,citiesthatlooktowardthefutureandlookattheinterestoftheircitizensshouldnotbeplanninglargeconcreteinfrastructuresthatdeterioratelivingconditions,introducenewhealthhazardsandmisshapethecityscapeforyearstocome.
Theinvestmentinanundergroundtransportsystemcouldinitiallybehigher.Butitalsooffersmanyadvantages.Thesocietalbenefitsofanundergroundsystemarenotjusttherapidtransportofpeople.Thereisnodirectimpactatthesurfaceprovidingcitizenswithamajoradvantagethatleavesspacetofurtherenhancethequalitiesofthecity.
Byplacingthemetroundergroundthereisalsoanelementofflexibility.AscanbeseenfromthedevelopmentofmetrosystemsinLondon,Parisandothercities–newlinescaneasilybeintroducedandcrossunderexistinglines.Doingthisatthesurfacewouldeitherbeverydifficultorresultinastackedelevatemetrosystemthatwouldevenfurtherdestroythecityscape.
4. Inconclusion
ThequestionofwhetherthemetroinBogotáneedstobeelevatedatthesurfaceorplacedbelowthesurfaceisnotatechnicaldiscussion.Itshouldalsonotbeadiscussionaboutcost.Aboveall,itisadiscussionontheBogotáofthefutureandhowthatcityshouldlook.Iflessonsaretobelearnedfromothercitiesworldwide,itisthatelevatedinfrastructurehasalwaysintheendproventobeabadlong-terminvestment.Removingtheelevatedinfrastructurehasledtointroducinganewqualityintoareasthathadbecomederelictbecauseofthepresenceofthatinfrastructure.Bynotbuildingthesestructuresinthefirstplace,butchoosingforanalternative,thepoliticiansofthedaycouldbemakingadecisionthatwouldbeapplaudedbytheircitizensinyearstocome.
ThenewmuseumbyCalatravaonthewaterfrontofRiodeJaneiroonlycameaboutthroughtheremovaloftheelevatedPeremitralHighwayandbuildingtwonewroadtunnelstocarrythetrafficbelowthesurface.Byremovingtheelevatedhighway,thewholeareacannowberevitalisedandthecitycentreisoncemoreconnectedwiththewaterfront.