The array of institutional factors affecting public transit operators' adoption of interoperable smart cards for regional, multioperator fare collection systems is examined. Although many transit agencies have implemented smart card technologies as stand-alone systems that cannot be used on other systems, others have done so as part of regional partner schemas in which multiple agencies with contiguous or overlapping service areas develop compatible systems. Through a review of the literature and in-depth interviews with industry experts, it was found that whereas interoperable systems have the benefit of allowing riders to use one fare card across multiple operators, such systems have proved difficult to form and coordinate as they require consensus among multiple parties. Four main institutional issues hindering implementation were identified: (a) staff and officials are often hesitant to relinquish local control over fare policies and collection because individual transit agencies are guided by different missions or priorities and tend to serve different markets of user groups; (b) the future of smart card technology is uncertain; (c) decentralized systems of decision making mean that interjurisdictional governance structures tend to be far more informal than intraorganizational operations and management; and (d) transit agencies typically lack the institutional capacity to comprehensively evaluate the costs and benefits of interoperable systems - and as a result, there are few rigorous evaluations of smart cards. Absent careful evaluations of costs and benefits, it cannot be known whether interoperable smart cards are overdue or premature. Thus, transit agencies' motivations to pursue smart cards are likely to remain ambiguous, and implementation is likely to remain halting.