What Cannot Be Cured Must Be Endured: Understanding Bridge Systems as Institutional Relics

Why do outdated bridges persist even when there are capable engineering management systems to remediate such systems and their associated costs? This study explores the institutional constraints that inhibit bridge managers from addressing these challenges. More specifically, it depicts bridges as institutional relics, whereby a bridge’s physical attributes reflect the accepted standards of the time and later persist even when those standards may change. Through a systematic analysis of the National Bridge Inventory, bridges are more likely to be institutional relics when built prior to the adoption of national design mandates (regulative-based relics) or in locales whose engineering norms conflict with these national standards (normative-based relics). Whereas state owners seem more sensitive to regulatory pressures, substate and private owners seem more sensitive to normative pressures. Finally, more physically constrained urban settings impede the ability of bridge managers to address those bridges that are identified as relics. These results are tied to contemporary issues in bridge management and used to propose policy actions to better address restrictive clearance issues.