  A strip of 2D HgTe topological insulator is studied. The same-spin edge
states in ideal system propagate in opposite directions on different sides of
the strip and do not mix by tunneling. Impurities, edge irregularities, and
phonons produce transitions between the contra-propagating edge states on
different edges. This backscattering determines the conductivity of an
infinitely long strip. It is found that the conductivity exponentially grows
with the strip width. The conductivity at finite temperature is determined
within the framework of the kinetic equation. In the same approximation the
non-local resistance coefficients of 4-terminal strip are found. At low
temperature the localization occurs and 2-terminal conductance of long wire
vanishes, but with the exponentially long (with respect to the strip width)
localization length. The transition temperature between kinetic and
localization behaviors has been found.
