The Quantitative Tools for Condition Assessment of Aging Infrastructure workshop was held May 4-5, 2010, to prioritize measurement and standards needs relative to inspection, maintenance, repair, and replacement of the Nation's physical infrastructure. The workshop focused on steel bridges, and the principal stakeholders in attendance included bridge owners, manufacturers of inspection equipment, and government and academic researchers. Discussion themes included (1) uncertainty in inspection data, (2) advanced sensors, (3) behavior of connections, and (4) mechanical response of materials.