Following on from our recap of the policy takeaways at the recent IGC Cities conference, today’s blog highlights a number of innovative and exciting academic studies that were presented

Jinhage, Amanda

Kaul, Upaasna

LSE Research Online

20/06/2017 The new urban agenda (Part 2): Urban complementarities - IGChttp://www.theigc.org/blog/the-new-urban-agenda-part-2-urban-complementarities/ 1/5Authors Upaasna KaulManaging Editor andEconomistEvaluation andCommunications, IGCLondon Hub Amanda JinhagePolicy EconomistIGC London Hub,Research Programme,ResearcherPublished on: 22 Feb 2016Countries: InternationalResearch themes: Cities The new urban agenda (Part 2):Urban complementaritiesFollowing on from our recap of the policytakeaways at the recent IGC Citiesconference, today’s blog highlights a numberof innovative and exciting academic studiesthat were presented.For the first time in history, more than half of the world’spopulation are living in cities. By 2045, the urban population ofthe world is expected to grow from 3.9 billion currently to over6 billion. Close to 90% of this expected growth will take placein developing countries. The need to clearly understand whatmakes cities liveable and productive has therefore never beengreater. What is potentially even more pressing is figuring outhow African and Asian cities can deal with the massivechallenges that arise from increases in population density, suchas congestion, contagion, and infrastructure sufficiency.On the 28-29  of January, the IGC gathered some of theworld’s foremost researchers and decision makers onurbanisation for a two day conference to explore the mainchallenges and opportunities facing developing cities. Thissecond annual IGC Cities Conference discussed issues fromoptimal city structure and zoning to transport andinfrastructure needed for functioning cities and the lessonslearned from history on providing clean water and sufficientsewage systems.Below we list three key ideas coming out of top level researchpresented at the conference:#1 Effective zoning and land use policies can increasewelfareIf it didn’t matter who your neighbours were or whichbusinesses were located close to your home, city planners wouldnot have much to do. However, a large body of evidence showsthat this is not the case. Location decisions, by individuals andfirms, are shaped by and in turn shape the productivity of acity’s economy. The resulting agglomeration effects cangenerate large positive impacts for a city. In the existence ofsuch spillover effects, city planners need to know what policies(i.e., zoning, infrastructure projects, etc.) best take advantage ofthe productivity gains from such clusters.A recent paper, presented by Costas Arkolakis (Yale), doesexactly this. Using a sophisticated ‘general equilibrium model’,Arkolakis (with co-authors Treb Allen and Xiangliang Li)th20/06/2017 The new urban agenda (Part 2): Urban complementarities - IGChttp://www.theigc.org/blog/the-new-urban-agenda-part-2-urban-complementarities/ 2/5Arkolakis (with co-authors Treb Allen and Xiangliang Li)accounts for various aspects of a city’s structure and spatiallinkages.  The model suggests that city planners can increaseresident welfare by restricting land use, or developing specific‘zones’ for urban land use.The authors apply the model using data from Chicago toevaluate zoning policy and to identify areas where relaxing orincreasing zoning policies might improve welfare (see graphbelow).  Such a model could be adapted to other cities. In orderfor the model to work, the researchers would need access todata on existing housing stocks, transportation, and commutingnetworks. Once that data is entered into the model, it canpredict welfare gains from opportunities to relax or reconfigurezoning policies.Figure 1. The welfare effects of re-zoning in ChicagoNote: The figure indicates the direction in which the modelpredicts areas in Chicago ought to be re-zoned to increase city-wide welfare. Red blocks indicate areas which should bereallocated to residential purposes and blue blocks indicateareas where spaces should be reallocated to commercialpurposes.#2 Improving transport infrastructure can decreaseinequalityRapid urban growth in developing countries is oftencharacterised by two features – congestion and inequality. Poortransport infrastructure not only exacerbates traffic congestion,but can also aggravate urban inequality levels. According tonew research by Nick Tsivanidis (University of Chicago Booth)improvements in transportation infrastructure could not onlyreduce commuting times but also facilitate better matchingbetween workers and jobs when residential and employmentclusters are spread further out.In on-going work, Tsivanidis is examining the effects ofimplementing a new bus rapid transit (BRT) system calledTransMilenio in Bogotá, Colombia. Opened in 2000,20/06/2017 The new urban agenda (Part 2): Urban complementarities - IGChttp://www.theigc.org/blog/the-new-urban-agenda-part-2-urban-complementarities/ 3/5TransMilenio in Bogotá, Colombia. Opened in 2000,TransMilenio has since become one of the world’s most usedBRT systems with 2.2 million trips per day. The staggeredrollout of the network, coupled with the fact that routes serveddifferent socio-economic groups, made it possible to evaluatethe distributional effects of the transport network. By leveraginga rich set of spatial data available both before and after theconstruction of the BRT, Tsivanidis is able to analyse a widevariety of distributional effects on commuting time, land valueand income.Findings, so far, suggest a sizable impact on land and labourmarkets. TransMilienio appears to be most heavily used by low-and middle-income groups, and despite comments on over-crowding and congestion on buses, high utilisation impliessignificant demand for the transit system from Bogotanos, ascommuters also reported reduced commuting times.Image credit: Mobilidade UrbanaGains from transportation infrastructure are the result ofimprovements in matching between workers and jobs. Thisassumes that some segments of the labour force will be bettersuited to certain kinds of jobs than others. If this holds, theninterventions to improve connectivity between workers and jobsbased in different parts of a city will result in productivity gainsfrom better quality job-matching.Results from Bogotá suggest that TransMilenio contributed towage increases of 7% for neighbourhoods that were less than500 meters from the stations, relative to neighbourhoods inperipheral areas. Further results will aim to quantify the impactof the transit system more clearly as well as the net effect onwelfare across low- and high-skill workers, and provide a cost-benefit estimate of the investment alongside an evaluation of itsinteraction with Bogotá’s land use policy.#3 Clean water and sanitation can, together, reduce infantmortalityContagion, or the rapid spread of disease in high-density areasis a significant risk factor and burden on the healthcare systemsof most developing countries. Much evidence already exists onthe importance of clean water to community health outcomes,but there is a gap in our understanding of the importance of20/06/2017 The new urban agenda (Part 2): Urban complementarities - IGChttp://www.theigc.org/blog/the-new-urban-agenda-part-2-urban-complementarities/ 4/5“but there is a gap in our understanding of the importance ofsewerage systems for similar outcomes. Untangling thisrelationship, Marcella Alsan (Stanford) presented an empiricalanalysis (co-authored with Claudia Goldin, Harvard) of aregional sewerage system and clean water provision in late 19century Massachusetts which resulted in the earliest recordedinstance of a significant decline in the infant mortality rate(IMR).Leveraging initiatives that provide both clean waterand sewerage may play a complementary role inreducing transmission. ”Over a relatively short period, IMR in greater Boston fell from163/1000 in 1896 to 151/1000 in 1898, and subsequently to100/1000 by 1915.  The decline can be attributed to a radicalchange in water and sewage treatment in the greater Bostonarea. The implementation of extensive water and sanitationinfrastructure allowed potable water to flow into homes, andprotected it from the sewerage being pumped into the BostonHarbour. Alsan and Goldin show that separately, changes inwater and sanitation had small or negligible effects, but takentogether, as illustrated below, the investments accounted forapproximately 37% of the total decline in log infant mortalityover the period.Figure 2: Impact on (Log) Infant Mortality Rate, before and aftersafe water and sewerageNote: The line at 0 gives the moment of both water andsewerage treatments by town.Clean water is not enough: Complexities of pathogentransmission pathwaysDiarrheal-related diseases are still a leading cause of childhoodand infant mortality in much of the developing world.Increasing incidences of anti-biotic resistance make treatment-focused approaches largely impractical. Good policy shouldinstead centre on identifying effective preventative measures fordisease transmission. Achieving this may require urban plannersand policymakers to incorporate a greater understandings of thepathways of pathogen transmission.Diarrheal-diseases are largely attributable to faecal-oralth20/06/2017 The new urban agenda (Part 2): Urban complementarities - IGChttp://www.theigc.org/blog/the-new-urban-agenda-part-2-urban-complementarities/ 5/5Diarrheal-diseases are largely attributable to faecal-oraltransmission, which can occur through multiple pathways.Sewerage provides a first order of defence, removing excrementfrom drinking water sources. This further reduces the risk oftransmission by flies that might otherwise be attracted byexcrement. Finally, excrement also enters the food supplythrough agriculture, which may intentionally or unintentionallybe exposed to contaminated water through run-off or flooding.Clean water is important not only for drinking, but for washingfood. Without sewerage systems however, clean water is notenough to disrupt potential pathogen transmission pathways.Leveraging initiatives that provide both clean water andsewerage may play a complementary role in reducingtransmission.This supports Alsan and Goldin’s proposition that investmentsin clean water and sewerage provide higher returns to healththan individual investments.  Gains to IMR are promising andshould inform urban policy agendas in developing countries.

The new urban agenda (part 2): urban complementarities

Abstract

Similar works

Full text

Available Versions

LSE Research Online