  This paper considers an unsignalized intersection used by two traffic
streams. A stream of cars is using a primary road, and has priority over the
other stream. Cars belonging to the latter stream cross the primary road if the
gaps between two subsequent cars on the primary road are larger than their
critical headways. A question that naturally arises relates to the capacity of
the secondary road: given the arrival pattern of cars on the primary road, what
is the maximum arrival rate of low-priority cars that can be sustained? This
paper addresses this issue by considering a compact model that sheds light on
the dynamics of the considered unsignalized intersection. The model, which is
of a queueing-theoretic nature, reveals interesting insights into the impact of
the user behavior on stability.
  The contributions of this paper are threefold. First, we obtain new results
for the aforementioned model that includes driver impatience. Secondly, we
reveal some surprising aspects that have remained unobserved in the existing
literature so far, many of which are caused by the fact that the capacity of
the minor road cannot be expressed in terms of the \emph{mean} gap size;
instead more detailed characteristics of the critical headway distribution play
a crucial role. The third contribution is the introduction of a new form of
bunching on the main road, called Markov platooning. The tractability of this
model allows us to study the impact of various platoon formations on the main
road on the capacity of the minor road.
