  Driving in urban environments often presents difficult situations that
require expert maneuvering of a vehicle. These situations become even more
challenging when considering large vehicles, such as buses. We present a path
planning framework that addresses the demanding driving task of buses in urban
areas. The approach is formulated as an optimization problem using the
road-aligned vehicle model. The road-aligned frame introduces a distortion on
the vehicle body and obstacles, motivating the development of novel
approximations that capture this distortion. These approximations allow for the
formulation of safe and non-conservative collision avoidance constraints.
Unlike other path planning approaches, our method exploits curbs and other
sweepable regions, which a bus must often sweep over in order to manage certain
maneuvers. Furthermore, it takes full advantage of the particular
characteristics of buses, namely the overhangs, an elevated part of the vehicle
chassis, that can sweep over curbs. Simulations are presented, showing the
applicability and benefits of the proposed method.
