  In this article, we propose an optimization-based integrated behavior
planning and motion control scheme, which is an interpretable and adaptable
urban autonomous driving solution that complies with complex traffic rules
while ensuring driving safety. Inherently, to ensure compliance with traffic
rules, an innovative design of potential functions (PFs) is presented to
characterize various traffic rules related to traffic lights, traversable and
non-traversable traffic line markings, etc. These PFs are further incorporated
as part of the model predictive control (MPC) formulation. In this sense,
high-level behavior planning is attained implicitly along with motion control
as an integrated architecture, facilitating flexible maneuvers with safety
guarantees. Due to the well-designed objective function of the MPC scheme, our
integrated behavior planning and motion control scheme is competent for various
urban driving scenarios and able to generate versatile behaviors, such as
overtaking with adaptive cruise control, turning in the intersection, and
merging in and out of the roundabout. As demonstrated from a series of
simulations with challenging scenarios in CARLA, it is noteworthy that the
proposed framework admits real-time performance and high generalizability.
