  We study the quench dynamics in free fermionic systems in the prototypical
bipartitioning protocol obtained by joining two semi-infinite subsystems
prepared in different states, aiming at understanding the interplay between
spatial correlations in the initial state and transport properties. Our
findings reveal that, under reasonable assumptions, the more correlated the
initial state, the slower the transport is. Such statement is first discussed
at qualitative level, and then made quantitative by introducing proper measures
of correlations and transport "speed". Moreover, it is supported for fermions
on a lattice by an exact solution starting from specific initial conditions,
and in the continuous case by the explicit solution for a wider class of
physically relevant initial states. In particular, for this class of states, we
identify a function, that we dub \emph{transition map}, which takes the value
of the stationary current as input and gives the value of correlation as
output, in a protocol-independent way. As a byproduct, in the discrete case, we
give an expression of the full counting statistics in terms of a continuous
kernel for a general correlated domain wall initial state, thus extending the
recent results in [Moriya, Nagao and Sasamoto, JSTAT 2019(6):063105] on the
one-dimensional XX spin chain.
