Historically, segregation has been measured on a subjective basis with state inspectors¿ determination based on visual information only. This is difficult because, particularly on surface mix, problems due to segregation may not appear for several months. Visual observation can identify only surface segregation, leaving that below the surface undetected. This report, jointly published by AASHTO and the National Asphalt Pavement Association, addresses segregation and how it can be eliminated to ensure the production of high-quality paving mixtures.