  We study the effects of local inhomogeneities, i.e., slow sites of hopping
rate $q<1$, in a totally asymmetric simple exclusion process (TASEP) for
particles of size $\ell \geq 1$ (in units of the lattice spacing). We compare
the simulation results of $\ell =1$ and $\ell >1$ and notice that the existence
of local defects has qualitatively similar effects on the steady state. We
focus on the stationary current as well as the density profiles. If there is
only a single slow site in the system, we observe a significant dependence of
the current on the \emph{location} of the slow site for both $\ell =1$ and
$\ell >1$ cases. When two slow sites are introduced, more intriguing phenomena
emerge, e.g., dramatic decreases in the current when the two are close
together. In addition, we study the asymptotic behavior when
  $q\to 0$. We also explore the associated density profiles and compare our
findings to an earlier study using a simple mean-field theory. We then outline
the biological significance of these effects.
