Area-wide Traffic Restriction in Lisbon City Center: Opportunity Lost or Mistake Avoided?

Abstract

Traffic restriction policies address economic, social, and environmental issues at the local level but may have effects beyond their area of application. Due to social and political opposition, a proposal to restrict all car traffic crossing the Lisbon old city centre (“Baixa”) was recently abandoned. This paper assesses the potential effects of this policy in terms of the distribution of noise exposures among populations belonging to different age and qualification groups. The changes in exposures were obtained through the modelling of motorised traffic and noise levels in the pre- and post-policy scenarios. It was assumed that car users react to the policy by seeking alternative routes or shifting to public transport. Under this assumption, the policy would have a modest effect on the reduction of noise exposures in their area of application. In addition, due to the redistribution of traffic, the policy would lead to a wide redistribution of exposures among neighbourhoods in other areas of the city, especially in areas with low-qualified populations. If provision is not made for alternatives for the suppressed traffic, this type of policies may have extensive impacts throughout the city and complex trade-offs between the levels of environmental quality of different social groups.