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...

High levels of particulate matter scaling less than 10 micrometers in diameter (PM10) in many urban areas have led to the introduction of binding PM10 limit values by the European Commission in 2005. Road transport in inner city areas is believed to be one of the main contributors to accumulated...

Cities face the daily challenge of providing people with access to different activities through their public transport systems. Despite its importance, there is little research on accessibility that focuses on the use of this mode and even less accounting for the impact of level of service (i.e....