Environmental impact assessments are an essential component of making decisions on transport infrastructure investments. Traditional procedures have proved ineffective for impacts that go beyond the scope of projects in isolation. Strategic environmental assessment has emerged in response, to...

We propose a theory-inspired measure of the accessibility of a city's center: the size of the surrounding area from which it can be reached within a specific time. Using publicly-available optimal routing software, we compute these "accessibility zones" for the 109 largest American and European...