Why does policy change over time? Adversarial policy communities, alternative policy arenas, and British trunk roads policy 1945–95

Abstract

This article examines some of the processes conditioning both policy stability and policy change. It focuses on how established policy communities (usually associated with policy stability) can exist alongside a powerful dynamic of change within the policy subsystem. By listing and analysing agents of exogenous and endogenous stability and change, it is concluded that the concepts of epistemic communities, advocacy coalitions and choice of ‘image’ and ‘venue’ are useful in explaining the co‐existence of stability and change. In the case of British trunk roads policy, this stability and change can be explained by the development of the road and environmental lobbies as rival adversarial policy communities operating in separate and competing policy arenas. The article concludes that, although one of the adversarial communities may hold an advantage over the other at a particular time, the scope for action in a number of different policy‐making arenas makes it unlikely that it will retain supremacy over time. Radical change is most likely to be brought about by factors exogenous to policy communities such as scientific and technological developments.