  Unsignalized intersection cooperation of connected and automated vehicles
(CAVs) is able to eliminate green time loss of signalized intersections and
improve traffic efficiency. Most of the existing research on unsignalized
intersection cooperation considers fixed lane direction, where only specific
turning behavior of vehicles is allowed on each lane. Given that traffic volume
and the proportion of vehicles with different turning expectation may change
with time, fixed lane direction may lead to inefficiency at intersections. This
paper proposes a multi-lane unsignalized intersection cooperation method that
considers flexible lane direction. The two-dimensional distribution of vehicles
is calculated and vehicles that are not in conflict are scheduled to pass the
intersection simultaneously. The formation reconfiguration method is utilized
to achieve collision-free longitudinal and lateral position adjustment of
vehicles. Simulations are conducted at different input traffic volumes and
turning proportion of incoming vehicles, and the results indicate that our
method outperformances the fixed-lane-direction unsignalized cooperation method
and the signalized method.
