In urban driving scenarios, autonomous vehicles are expected to conform to traffic rules covering traffic lights, traversable and non-traversable traffic lines, etc. In this article, we propose an optimization-based integrated decision-making and control scheme for urban autonomous driving. Inherently, to ensure the compliance with traffic rules, an innovative design of potential functions (PFs) is presented to characterize various traffic rules that are commonly encountered in urban driving scenarios, and these PFs are further incorporated as part of the model predictive control (MPC) formulation. In this sense, it circumvents the necessity of typical hand-crafted rule design, and high-level decision-making is attained implicitly along with control as an integrated architecture, facilitating flexible maneuvers with safety guarantees. As demonstrated from a series of simulations in CARLA, it is noteworthy that the proposed framework admits real-time performance and high generalizability.