Quantifying Vehicle and Pedestrian Access
Street systems have undergone only a few major changes since their invention five millennia ago: a major one was separating pedestrians from vehicles, first with sidewalks, more recently with shopping centers. But few changes have been as transforming as the structure of grid-form street systems gave way over the past 60 years and the function of street systems narrowed precipitously. This chapter focuses on deformations in the systems that carry vehicles and pedestrians and their effect on access. It aims to answer the following questions: What evidence indicates impairment? When does a quantitative change in access result in a qualitative change of access? What is the structure of substantially impaired access? The analyses are in the form of a field experiment wherein an effect is evident but a cause is not (Brown 2008(b)).