The IPAT-model developed by Ehrlich and Holdren is widespread in ecological economics in order to quantify the impact of population growth on environmental deterioration. We comment on this model and extensions proposed by several authors from a theoretical and empirical point of view.

We analyse the impacts that infrastructure provision has on long run urban development. The topic is of major importance to policy-makers when deciding whether or not to invest in major infrastructure projects. The analysis helps policy-makers to understand the intended, and potentially...