Long-term Pavement performance, construction, traffic, and environmental data for more than 2500 pavement sections in the United States and Canada. More than a dozen experimental designs address specially constructed and existing asphalt and concrete pavements, and maintenance and rehabilitation strategies. Data collection has been on-going since 1990. About one third of the pavement sections are still under study. New warm-mix asphalt concrete pavement overlay sections are currently being recruited and constructed.