  Multi-lane roads are typical scenarios in the real-world traffic system.
Vehicles usually have preference on lanes according to their routes and
destinations. Few of the existing studies looks into the problem of controlling
vehicles to drive on their desired lanes. This paper proposes a formation
control method that considers vehicles' preference on different lanes. The
bi-level formation control framework is utilized to plan collision-free motion
for vehicles, where relative target assignment and path planning are performed
in the upper level, and trajectory planning and tracking are performed in the
lower level. The collision-free multi-vehicle path planning problem considering
lane preference is decoupled into two sub problems: calculating assignment list
with non-decreasing cost and planning collision-free paths according to given
assignment result. The Conflict-based Searching (CBS) method is utilized to
plan collision-free paths for vehicles based on given assignment results. Case
study is conducted and simulations are carried out in a three-lane road
scenario. The results indicate that the proposed formation control method
significantly reduces congestion and improves traffic efficiency at high
traffic volumes, compared to the rule-based method.
