  In this work, we study the minimal time to steer a given crowd to a desired
configuration. The control is a vector field, representing a perturbation of
the crowd velocity, localized on a fixed control set. We will assume that there
is no interaction between the agents. We give a characterization of the minimal
time both for microscopic and macroscopic descriptions of a crowd. We show that
the minimal time to steer one initial configuration to another is related to
the condition of having enough mass in the control region to feed the desired
final configuration. The construction of the control is explicit, providing a
numerical algorithm for computing it. We finally give some numerical
simulations.
