Assessment of the Performance of Vital Long-Span Bridges in the United States describes the types and levels of assessments necessary for capturing the lifetime performance of long-span bridges and emphasizes the distinction between performance and condition assessments. Long-span bridges are a living tribute to the engineering feats and accomplishments of their designers and builders. This report contains up-to-date engineering assessment concepts, elaborates on some past catastrophic failures, and relates the lack of engineering performance assessments in these case histories. The elements and parameters, which may govern whether these special bridges have the sustainability to perform well for long-term serviceability and during extreme events, are discussed. Bridge engineers who are involved in preserving long-span bridges and concerned with their vulnerability and weakness will find this book of interest for future load and force scenarios. 36 pp.