  The effect of the absorbing sites with an absorbing rate $\beta_{0}$, in both
one absorbing site (one way out) and two absorbing sites (two ways out) in a
road, on the traffic flow phase transition is investigated using numerical
simulations in the one-dimensional cellular automaton traffic flow model with
open boundaries using parallel dynamics.In the case of one way out, there exist
a critical position of the way out $ i_{c1}$ below which the current is
constant for $\beta_{0}$$<$$\beta_{0c2}$ and decreases when increasing
$\beta_{0}$ for $\beta_{0}$$>$$\beta_{0c2}$. When the way out is located at a
position greater than $ i_{c2}$, the current increases with $\beta_{0}$ for
$\beta_{0}$$<$$\beta_{0c1}$ and becomes constant for any value of $\beta_{0}$
greater than $\beta_{0c1}$. While, when the way out is located at any position
between $ i_{c1}$ and $ i_{c2}$ ($ i_{c1}$$<$$ i_{c2}$), the current increases,
for $\beta_{0}$$<$$\beta_{0c1}$, with $\beta_{0}$ and becomes constant for
$\beta_{0c1}$$<$$\beta_{0}$$<$$\beta_{0c2}$ and decreases with $\beta_{0}$ for
$\beta_{0}$$>$$\beta_{0c2}$. In the later case the density undergoes two
successive first order transitions; from high density to maximal current phase
at $\beta_{0}$$=$$\beta_{0c1}$ and from intermediate density to the low one at
$\beta_{0}$$=$$\beta_{0c2}$. In the case of two ways out located respectively
at the positions $ i_{1}$ and $ i_{2}$, the two successive transitions occur
only when the distance $i_{2}$-$i_{1}$ separating the two ways is smaller than
a critical distance $d_{c}$. Phase diagrams in the ($\alpha,\beta_{0}$),
($\beta,\beta_{0}$) and ($i_{1},\beta_{0}$) planes are established. It is found
that the transitions between Free traffic, Congested traffic and maximal
current phase are first order.
