  Molecular motors are macromolecular complexes which use some form of input
energy to perform mechanical work. The filamentary tracks, on which these
motors move, are made of either proteins (e.g., microtubules) or nucleic acids
(DNA or RNA). Often, many such motors move simultaneously on the same track and
their collective properties have superficial similarities with vehicular
traffic on highways. The models we have developed provide ``unified''
description: in the low-density limit, a model captures the transport
properties of a single motor while, at higher densities the same model accounts
for the collective spatio-temporal organization of interacting motors. By
drawing analogy with vehicular traffic, we have introduced novel quantities for
characterizing the nature of the spatio-temporal organization of molecular
motors on their tracks. We show how the traffic-like intracellular collective
phenomena depend on the mechano-chemistry of the corresponding individual
motors.
