ABSTRACT: Objective: Each year, more than 30,000 deaths occur on U.S. roads. Recognizing the magnitude and persistence of this public health problem, a number of U.S. cities have adopted a relatively new approach to prevention, termed Vision Zero (VZ). VZ has been adopted by more than 30 U.S. cities and calls for creating a transportation system that ensures that no road traffic crash results in death or serious injury. A core component of VZ is strong multidisciplinary and multisector stakeholder engagement, and cities adopting VZ often establish a VZ coalition to foster stakeholder collaboration. However, there is little information on the structure, development, and functioning of coalitions working to achieve VZ and on tools available to study and evaluate such coalition functioning. We sought to describe the characteristics of prominent U.S. VZ city coalitions and context surrounding VZ uptake and advancement in these cities. Moreover, we demonstrate use of network analysis as one tool for exploring the structure of interorganizational relationships in coalitions. Methods: We conducted case studies of 4 prominent U.S. VZ city coalitions in 2017-2018. We summarized coalition members' characteristics and responses to questions about their cities' VZ adoption, planning, and implementation. We asked each coalition member to provide information on their contact frequency, perceived productivity, and resource sharing with every other coalition member in their city and used network analysis techniques in 2 cities to understand the structures and relationships in coalitions. Results: Findings indicated that government agencies generally constituted the majority of coalition members and often played central roles in terms of coalition network contact, productivity, and resource flow. Other emerging similarities regarding coalition establishment and VZ implementation included the need for political support, the importance of formal plan development, and increased collaboration and cooperation among partners. Conclusions: Organizational network analyses, enriched with coalition member interviews, can elucidate key aspects of coalition creation, attributes, and relationship structure. The case studies of leading VZ coalition networks presented here highlight the use of these tools. Ultimately, understanding associations between VZ network structures and attributes and road safety outcomes could help inform effective coalition adoption, implementation, and maintenance to optimize safety outcomes.