ABSTRACT
This chapter examines the mobility and plasticity of the city and examines the ways in which investigators can match that mobility and plasticity. A mobile target demands mobility from an investigator, to paraphrase Cresswell's epigram. Mechanical mobility in the urban milieu is also a "Janus two-faced creature", on the one hand offering up the possibility of liberation from the immediate environment; on the other hand, imprisoning people in congestion and gridlock. There is also the speed of the various technologies now so far embedded within our own selves and within the fabric of the city that they must be considered as constituent parts of them both. People have come to inhabit congested, gridlocked, and health-threatening city environments through being trapped in cocooned, moving iron bubbles. The velocity of logistics and transportation, mechanical in mode yet plugged into the modes of the biological and the digital, also move about and around the city in a thousand different directions.
