Abstract

With a growing majority of the world’s population residing in cities, it is vital to advance a shift to low-emission urban mobility in order to mitigate climate change. Despite the fundamental role played by infrastructure, daily decisions and routines of individuals ultimately generate traffic. When people choose a conventionally fueled private car, it causes externalities detrimental for both individuals and the urban system as a whole: congestion, noise, greenhouse gas emissions, air pollution. Empirical studies show that the awareness of and exposure to those do not provide enough motivation for people to shift to more sustainable travel modes. Convenience overpowers environmental values. To break the habits and manage emissions, authorities must deploy incentives or sanctions — structural, regulative, economic, persuasive — that can increase the comparative advantage of low-carbon traffic modes. The potential of different initiatives to reduce traffic emissions is invaluable information for decision makers. Our contribution investigates the variety of possible ways to advance the desired shift, and highlights the importance, challenges, and key factors of high quality impact evaluations. A functional approach to test and evaluate traffic initiatives is multidisciplinary, with ways to quantify people’s behavior and preferences, traffic emerging from them, and the resulting atmospheric emissions. By shedding light on reliable approaches to reveal the real impacts of traffic initiatives, the efforts for climate change management may be reinforced.