Pollution and congestion in urban areas: The effects of low emission zones

The great weight that the car has as a means of mobility in large cities generates significant negative externalities both in terms of pollution and congestion. The goal of this paper is to examine the effectiveness of low emission zones (LEZs) and to compare it with the existing results in literature on the effectiveness of urban tolls. First, we build up a theoretical model that departs from De Borger and Proost (2012), who study the effects of urban tolls on congestion, by incorporating pollution into the analysis and LEZs as an alternative (quantity-based) policy measure. Then we perform an econometric analysis taking advantage of a unique and extremely original panel of large European urban areas over the period 2008–2016, using data on congestion from TomTom and data on pollution (PM2.5) from environmental sciences. We conclude that LEZs can curb pollution. They are particularly effective in highly polluted cities, when they are applied to a wide area of the city, and/or when they are stringent in the type of restricted vehicles. Instead, LEZs are ineffective in mitigating congestion. This is a very relevant result, given the growing importance of LEZs in Europe.