Urban congestion represents one of the most pressing challenges facing modern cities, imposing significant economic, environmental, and social costs on urban populations worldwide. Autonomous vehicles (AVs) have emerged as a potentially transformative technology that could fundamentally reshape urban transportation systems and significantly reduce traffic congestion. This article examines the mechanisms through which autonomous vehicles could alleviate urban congestion, including improved traffic flow efficiency, optimized routing, enhanced vehicle sharing, and reduced parking demand. Through analysis of current research and technological developments, this paper evaluates both the promising potential and significant challenges associated with autonomous vehicle deployment in urban environments, providing insights into the conditions necessary for AVs to achieve meaningful congestion reduction.