Autonomous vehicles (AVs) are diffusing in cities worldwide, propelled by expectations for enhanced safety and sustainability. This study examines urban innovation mechanisms across 30 pilot cities in China, analyzing AV experimentation activities, policy mixes, and emphasized innovation system functions using a novel dataset of 116 pilot projects and 881 policy documents. Combining qualitative content analysis and K-means clustering, we identify three city archetypes: Innovation Leaders, Specialized Developers, and Emerging Participants. These groups reveal distinct configurations of innovation mechanisms and development trajectories shaped by local priorities and capacities. Innovation Leaders pursue end-use-focused AV innovation through forward-looking institutional arrangements facilitating market formation, whereas other cities focus on industrial manufacturing and infrastructure development. Empirically, this heterogeneity reflects diversified value-chain positioning across city archetypes. As a core theoretical and methodological contribution, our study reveals multiple, context-dependent urban pathways for building an AV innovation system, showing how municipal governments dynamically combine innovation mechanisms over time.