Clearing the air after "dieselgate": Time for European regulators to experiment with participatory governance

Since it erupted in 2015, the so-called "dieselgate" scandal has revealed severe shortcomings in car manufacturers' efforts to reduce the impacts of driving on both global climate change and local air quality. In the European Union context, this controversy has raised questions about the trustworthiness of carmakers, and about the accuracy of the emissions measurements upon which key regulation is currently based. Just as importantly, however, it has also precipitated growing tensions between regulatory authorities situated in municipalities, national governments, and Brussels itself. Thus, even as European lawmakers have responded to the scandal by seeking to revamp and tighten up official "laboratory" vehicle emissions tests, growing citizen concern about the impact of vehicles on urban air quality is already having significant impacts across a multitude of European cities. Municipal authorities in Germany, for example - including in Stuttgart, the hometown of several major carmakers - have recently been compelled by court rulings to introduce outright bans on many older models of diesel vehicle, following legal challenges brought by environmental groups. That such bans have been upheld in Germany's highest court despite opposition from both state and federal governments underlines the need to view dieselgate as a knowledge controversy with distinctly geopolitical dimensions. In this commentary, we contend that questions about the accuracy of vehicle emissions measurements cannot be separated from geopolitical and scalar tensions over regulatory authority. Far from seeing such complexity as a barrier to the effective "closure" of the dieselgate scandal, however, we suggest that European regulators stand to gain much from adopting a more open and responsive position towards citizens' concerns about vehicle emissions, as well as the plurality of forms of knowledge and experience upon which they are based.