particle. The motion of the particles from left to right is defined by (local) transition rates between adjacent sites. The corresponding hopping rates $p_j$ describing the transitions of particles to their right neighbours are inhomogeneous. We will focus on a binary distribution with two possible values $p_j=p$ or $p_j=q$ at each site $j$ where $q<p$. Sites with transition rate $p_j=q$ will be referred to as *defect sites*, while a site with transition rate $p_j=p$ is called a *non-defect site*. In the following we will call a stretch of $l$ consecutive defect sites a *bottleneck of size $l$*.

The boundaries of the system are connected to reservoirs so that particles can enter at the left end ($j=1$) and leave at the right end ($j=L$). The (fixed) densities $\rho_0$ and $\rho_{L+1}$ of the reservoirs control the effective entry and exit rates, $\alpha:=\rho_0$ and $\beta:=1-\rho_{L+1}$, respectively.

Langmuir kinetics is realized by creation and annihalition of particles in the bulk. This can be interpreted as particle exchange with a bulk reservoir and corresponds to attachment and detachment processes in the biological context. The corresponding rates will be considered to be homogeneous, i.e. independent of the position, throughout this paper [^1].

For large system size 