, Volume 42, Issue 6, pp 1063–1079 | Cite as

Heterogeneity in the reaction of traffic flows to road pricing: a synthetic control approach applied to Milan

  • Marco Percoco


Local governments are increasingly adopting road pricing schemes to curb pollution and congestion in the cities. Despite its popularity, few empirical studies have made an attempt to estimate the effectiveness of such interventions. The aim of this paper is to assess the impact of road pricing on traffic flows by means of a synthetic control approach which allows for a wide heterogeneity of treatment effects. By using a large sample of 75 types of vehicles entering the centre of Milan between 2008 and 2012, we evaluate the enforcement of the road pricing scheme occurred in January 2012 across 20 types of vehicles. We have found a large variation in the reaction of traffic flows and a significant effect in terms of vehicles reduction after pricing for cars and for some types of commercial vehicles. Interestingly and surprisingly, no effect is detected for vehicles whose access in the city centre was forbidden.


Road pricing Synthetic control Traffic flows Milan 



I am grateful to Marco Bedogni and Silvia Moroni of AMAT for their guidance through and work with the data. This research was carried out during a visit at LSE Department of Geography and Environment whose hospitality is gratefully acknowledged.


  1. Abadie, A., Diamond, A., Hainmueller, J.: Synthetic control methods for comparative case studies: estimating the effect of California’s Tobacco Control Program. J. Am. Stat. Assoc. 105, 490 (2010)CrossRefGoogle Scholar
  2. Abadie, A., Diamond, A., Hainmueller, J.: Comparative politics and the synthetic control method. MIT political science department research paper no. 2011–25, June (2012)Google Scholar
  3. Abadie, A., Gardeazabal, J.: The economic costs of conflict: a case study of the Basque Country. Am. Econ. Rev. 93(1), 112–132 (2003)CrossRefGoogle Scholar
  4. AMAT: Valutazione Nuovi Scenari di Regolamentazione degli Accessi alla ZTL Cerchia dei Bastioni. Comune di Milano, Milan (2011)Google Scholar
  5. AMMA: Ecopass - Primi Dati di Marzo. Comune di Milano, Milan (2008a)Google Scholar
  6. AMMA: Monitaraggio indicatori ecopass. Prime Valutazioni, Comune di Milano, Milan (2008b)Google Scholar
  7. AMMA: Sintesi Risultati Conseguiti e Scenari di Sviluppo. Comune di Milano, Milan (2008c)Google Scholar
  8. Banister, D.: Critical pragmatism and congestion charging in London. Int. Soc. Sci. J. 176, 248–264 (2003)Google Scholar
  9. Barnoya, J., Glantz, S.: Association of the California tobacco control program with declines in lung cancer incidence. Cancer Causes Control 15, 689–695 (2004)CrossRefGoogle Scholar
  10. Chen, Y., Whalley, W.: Green infrastrucutre: the effects of Urban rail transit on air quality. Am. Econ. J. 4(1), 58–97 (2012)Google Scholar
  11. Davis, L.W.: The effect of driving restrictions on air quality in Mexico city. J. Polit. Econ. 116(1), 38–81 (2008)CrossRefGoogle Scholar
  12. Eliasson, J.: A cost-benefit analysis of the Stockholm congestion charging system. Transp. Res. Part A 43(4), 468–480 (2009)Google Scholar
  13. Eliasson, J., Hultkrantz, L., Nerhagen, L.: The Stockholm congestion charging trial 2006: overview of the effects. Transp. Res. Part A 43(3), 240–250 (2009)Google Scholar
  14. Fichtenberg, C.M., Glantz, S.A.: Controlling tobacco use. New Engl. J. Med. 344, 1798–1799 (2001)Google Scholar
  15. Givoni, M.: Re-assessing the results of the London congestion charging scheme. Urban Stud. 49(5), 1089–1105 (2012)CrossRefGoogle Scholar
  16. Ieromonachou, P., Potter, S., Warren, J.P.: Norway’s urban toll rings: evolving towards congestion charging. Transp. Policy 13(5), 29–40 (2006)CrossRefGoogle Scholar
  17. Ison, S., Rye, T.: Implementing road user charging: the lessons learnt from Hong Kong. Camb. Central Lond., Transp. Rev. 25(4), 451–465 (2005)Google Scholar
  18. Mackie, P.: The London congestion charge: a tentative economic appraisal - a comment on the paper by prud’homme and bocarejo. Transp. Policy 12(3), 288–290 (2005)CrossRefGoogle Scholar
  19. Percoco, M.: Urban transport policy and the environment: evidence from Italy. Int. J. Transp. Econ. 37(2), 223–245 (2010)Google Scholar
  20. Percoco, M.: The impact of road pricing on housing prices: preliminary evidence from Milan. Università Bocconi, mimeo (2012)Google Scholar
  21. Percoco, M.: Is road pricing effective in abating pollution? Evidence from Milan, Transp. Res. D, forthcoming (2013a)Google Scholar
  22. Percoco, M.: The effect of road pricing on traffic composition: evidence from a natural experiment in Milan, Italy, Transport Policy, forthcoming (2013b)Google Scholar
  23. Percoco, M.: Regional perspectives on policy evaluation, Springer, forthcoming (2013c)Google Scholar
  24. Prud’homme, R., Bocarejo, J.P.: The London congestion charge: a tentative economic appraisal. Transp. Policy 12(3), 279–287 (2005)CrossRefGoogle Scholar
  25. Quddus, M.A., Carmel, A., Bell, M.G.H.: The impact of congestion charge on retail: the London experience. J. Transp. Econ. Policy 41(1), 113–133 (2007)Google Scholar
  26. Raux, C.: Comments on “the London congestion charge: a tentative economic appraisal”. Transp. Policy 12(4), 368–371 (2005)CrossRefGoogle Scholar
  27. Rotaris, L., Danielis, R., Marcucci, E., Massiani, J.: The Urban road pricing scheme to curb pollution in Milan, Italy: description, impacts and preliminary cost-benefit Anal- ysis assessment. Transp. Res. A 44, 359–375 (2010)Google Scholar
  28. Santos, G.: Urban congestion charging: a comparison between London and Singapore. Transp. Rev. 25(5), 511–534 (2005)CrossRefGoogle Scholar
  29. Santos, G., Bhakar, J.: The impact of London congestion charging scheme on the generalised cost of car commuters to the city of London from a value of travel time Savings perspecitve. Transp. Policy 13(1), 22–33 (2006)CrossRefGoogle Scholar
  30. Santos, G., Fraser, G.: Road pricing: lessons from London. Econ. Policy 21(46), 263–310 (2006)CrossRefGoogle Scholar
  31. Santos, G., Shaffer, B.: Preliminary results of the London congestion charging scheme. Public Works Manag. Policy 9, 164–168 (2004)CrossRefGoogle Scholar
  32. van den Berg, V., Verhoef, E.T.: Winning or losing from dynamic bottleneck congestion pricing? the distributional effects of road pricing with Heterogeneity in values of time and schedule delay. J. Public Econ. 95(7–8), 983–992 (2011)CrossRefGoogle Scholar

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© Springer Science+Business Media New York 2014

Authors and Affiliations

  1. 1.Department of Institutional Analysis and Public ManagementUniversità BocconiMilanoItaly

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