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Accueil > Recherches > Méthodes et outils > Modélisation prospective

NEDUM-2D model

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NEDUM-2D model

NEDUM-2D has been developed in CIRED to model how the inhabitants choose to locate in a city, how policies can influence their choice, and what are the socio-economic effects associated to these policies.

The model has been designed to create long-term scenarios for city expansion, based on scenarios describing future land-use and transport policies in the city, on demographic scenarios on the future total population, and on global “techno-economic” scenarios on future income, construction cost and transport cost evolution. These techno-economic scenarios can be produced through global general equilibrium prospective models, such as Imaclim-R developed in CIRED (Rozenberg et al. 2010), or Markal/TIMES developed by IEA ETSAP . NEDUM-2D can therefore be seen as a tool to downscale at city scale global scenarios produced by such models.

Figure 1 : Description of NEDUM-2D model

Model description

NEDUM-2D simulates the spatial distribution of land and real estate values, dwelling sizes, population density, building height and density, and their evolution over time (Figure 1). (Gusdorf et Hallegatte 2007 ; Viguié et Hallegatte 2012 ; Viguié, Hallegatte et Rozenberg 2014) It is a dynamic model which relies on the classical urban economics framework (Fujita 1989), but is able to capture the dynamics of urban systems, and the importance of inertia. To produce scenarios going until the end of the century, it uses only general and fundamental economic principles, which are likely to remain constant over the long term.

Three main mechanisms drive the model. First, we suppose that households choose their accommodation location and size by making a trade-off between the time and money they spend for transport (i.e. to commute to their jobs) and the real estate price level (or, equivalently, between the proximity to the city center and the housing surface they can afford).

Second, real estate developers choose to build more or less housing (i.e. larger or smaller building) at a specific location, depending on the local level of real estate prices. When these prices are low, developers tend to build low density buildings, and when these prices are high, they tend to build high density buildings.

Figure 3 : Simulated urbanized area compared to actual urbanized area.
Actual urban area appears in black (Source : Corinne Land Cover and IAU), whereas model simulation appears in transparent green.

Third, we suppose that various city characteristics do not change and adjust at the same speed. For instance, rents can change very quickly, whereas buildings characteritsics evolve over a much longer timescale. Building depreciation is also very slow, leading to path dependency and lock-ins in city evolution.

Using these mechanisms, it is possible to determine the structure of the city from information on population size, households’ income, transport network location, building construction costs and developers behavior parameters.

This model has been first calibrated on Paris urban area. A validation of the model over the 1900–2010 period shows that the model reproduces the available data on the city’s evolution fairly faithfully (Figure 2), suggesting that the model captures the main determinants of city shape evolution. It also well reproduces the spatial distribution of dwelling size, population density, and rents in the urban area (Figure 3).

Figure 2 : Comparison between actual Paris urban area structure and NEDUM simulation, for the same years.

Related Publications

You can click on the links to find the full texts or the preprints.

- Viguie et al. 2018 "Modeling urban expansion across a panel of diverse cities", poster at the IPCC Cities and Climate Change Science Conference, Edmonton, Canada, March 2018

- B Yin, L Liu, N Coulombel, V Viguié 2018 « Appraising the environmental benefits of ride-sharing : the Paris region case study » Journal of Cleaner Production, 177, 888-898

- B Yin, L Liu, N Coulombel, V Viguié 2017 « Evaluation of ridesharing impacts using an integrated transport land-use model : a case study for the Paris region » Transportation Research Procedia 27, 824-831

- P Avner, SR Mehndiratta, V Viguie, S Hallegatte 2017 « Buses, houses or cash ? socio-economic, spatial and environmental consequences of reforming public transport subsidies in Buenos Aires » World Bank Working papers

- Julie Prud’homme ; Isabelle Coll ; Arthur Elessa-Etuman ; Vincent Viguié ; Nicolas Coulombel. 2017. Coupling spatialized models to evaluate the effects of urban densification on air quality in the Paris metropolitan area. International Journal of Spatial, Temporal and Multimedia Information Systems. International Journal of Spatial, Temporal and Multimedia Information Systems

- T Houet, C Marchadier, G Bretagne, MP Moine, R Aguejdad, V Viguié et al. 2016. "Combining narratives and modelling approaches to simulate fine scale and long-term urban growth scenarios for climate adaptation" Environmental Modelling & Software 86, 1-13

- R Aguejdad, O Doukari, T Houet, P Avner, V Viguié. 2016. "Etalement urbain et géoprospective : apports et limites des modèles de spatialisation. Application aux modèles SLEUTH, LCM et NEDUM-2D". Cybergeo : European Journal of Geography

- A Lemonsu, V Viguié, M Daniel, V Masson. 2015. "Vulnerability to heat waves : Impact of urban expansion scenarios on urban heat island and heat stress in Paris (France)" Urban Climate 14, 586-605

- Viguié, V. 2015 "Cross-commuting and housing prices in a polycentric modeling of cities" FAERE Working papers n°2015.09.

- MUSCADE project final report

About this project :

- Viguie, V. ; Hallegatte, S. 2014. Urban infrastructure investment and rent-capture potentials. Policy Research working paper ; no. WPS 7067. Washington, DC : World Bank Group.
- Masson, V., C. Marchadier, L. Adolphe, R. Aguejdad, P. Avner, M. Bonhomme, G. Bretagne, et al. 2014. “Adapting Cities to Climate Change : A Systemic Modelling Approach.” Urban Climate 10 : 407-29. (open access article)

- Avner, Paolo ; Rentschler, Jun ; Hallegatte, Stephane. 2014. Carbon price efficiency : lock-in and path dependence in urban forms and transport infrastructure. Policy Research working paper ; no. WPS 6941. Washington, DC : World Bank Group.

- Köhler, Ristimäki, Viguié, Felieu et al., chapter "A review and analysis of quantitative integrated environmental assessment methods for urban areas" in the book Dawson, Richard, Annemie Wyckmans, Oliver Heidrich, Jonathan Koher, Stephen Dobson, and Efren Feliu. 2014. Understanding Cities : Advances in Integrated Assessment of Urban Sustainability. Centre For Earth Systems Engineering Research.

- Bonhomme, Masson, and Viguié. 2013. “Histoire et Prospective Avec Le Projet Muscade.” Les Cahiers de l’IAU, December.

- Viguié, V., S. Hallegatte, and J. Rozenberg. 2014. “Downscaling Long Term Socio-Economic Scenarios at City Scale : A Case Study on Paris.” To Be Published in Technological Forecasting and Social Change. (Postprint)

- PhD Thesis Marion Bonhomme. 2013. “Contribution À La Génération de Bases de Données Multi-Scalaires et Évolutives Pour Une Approche Pluridisciplinaire de L’énergétique Urbaine”. Toulouse, France : Université de Toulouse.
- Avner, Viguié and Hallegatte. 2013 "Modélisation de l’effet d’une taxe sur la construction : le Versement pour Sous-Densité". Débats et politiques, revue de l’OFCE, n°128.

- Viguié and Hallegatte. 2012. Trade-offs and Synergies in Urban Climate Policies. Nature Climate Change 2 (3) (Article) (Supplementary Online Material)

- PhD Thesis Viguié, V. 2012. “Urban Dynamics Modelling, Application to Economic Assessment of Climate Change”. Paris, France : CIRED, Université Paris Est. Summary Manuscript

- Viguié, and Hallegatte. 2010. Une taxe carbone peut-elle rendre l’agglomération parisienne plus dense ? In Economie et développement urbain durable. Presses de l’Ecole des mines.

Research projects

- Transport Policies for Sustainable and Inclusive Growth (2016-1017). World Bank Strategic Research Program. Lead : Harris Selod.

- DRAGON (Dynamics of Green Growth in European and Chinese Cities), 2015-...

- VITE !, 2014-....

- Vurca : VURCA research project studies cities vulnerability to future heat-waves, in order to provide first insights on the complex interaction between city economies and climate change and on the viability and effectiveness of identified adaptation options.

- Muscade : MUSCADE project will focus on three items involved into city sustainable development : energy, city structure, and climate change, closely linked to each others, at both global and local scales. This project is intended to open new interdisciplinary research areas on sustainable cities and to increase urban planners awareness on energy issues within the city, given the climate change. By identifying leverages, the framework could also help future decisions concerning buildings, local energy production, and urban regulations.

- Acclimat : ACCLIMAT research project aims to study urban development, urban micro-climate, and climate change process interactions. A numerical modelling framework will be developed to couple physical models and socio-economics urban models, which will be driven by local climate change and socio-economic scenarios, including macro-economics, land-use, building materials, technologic and transportation assumptions.

- COST Action TU0902, Integrated assessment technologies to support the sustainable development of urban areas.

Technical note

Technical note

See also here a presentation poster (presented at the IPCC Cities and Climate Change Science Conference, Edmonton, Canada, March 2018


Vincent Viguié