  Processive molecular motors which drive the traffic of organelles in cells
move in a directed way along cytoskeletal filaments. On large time scales, they
perform motor walks, i.e., peculiar random walks which arise from the repeated
unbinding from and rebinding to filaments. Unbound motors perform Brownian
motion in the surrounding fluid. In addition, the traffic of molecular motors
exhibits many cooperative phenomena. In particular, it faces similar problems
as the traffic on streets such as the occurrence of traffic jams and the
coordination of (two-way) traffic. These issues are studied here theoretically
using lattice models.
