  Totally asymmetric simple exclusion process (TASEP) sets the paradigm for
one-dimensional driven single file motion. We study a periodic TASEP with two
``road blocks'' or defects of different kinds, one point and another extended,
across which particle flows are inhibited. We show how the interplay between
particle number conservation and competition between the defects lead to
inhomogeneous steady states with localised domain walls (LDW) or static density
shocks, whose locations jump discontinuously, indicating a first order
transition between these LDW states, as the system passes from being controlled
by one defect to the other. When the defects are ``competing'', instead of an
LDW a pair of delocalised domain walls are found, none of which can penetrate
the extended defect. A minimum current principle can be used to identify the
dominant defect that controls the domain wall formations.
