Spillover effects of central cities on sustainability efforts in a metropolitan area

Metropolitan cities can serve as laboratories of sustainable development by experimenting with innovative sustainability programs while leveraging the advantages of metropolitan areas. With the importance of cities’ sustainability efforts, scholars have increasingly explored what factors motivate local governments to implement voluntary sustainability programs by focusing on internal government and community characteristics. However, what is missing in the previous discussion is whether city governments respond to sustainability efforts by other government entities, especially neighboring local governments. Drawing on institutional and policy diffusion theories, we analyzed the sustainability programs of 251 suburban cities in 66 metropolitan areas. We find that suburban cities are likely to consider sustainability efforts of central cities in the same metropolitan area when determining the extent to which they implement their sustainability programs. However, they are not necessarily responsive to sustainability efforts of nearby suburban cities. Our research sheds light on how local governments’ sustainability policy decisions are affected by their relationships with other local governments. It also provides policy implications for the important role of central cities in facilitating collective sustainability efforts in metropolitan areas.