Federal Highway Administration website (FHWA): http://www.fhwa.dot.gov/

Pavement Interactive:https://pavementinteractive.org/ 

National Center of Asphalt Technology (NCAT): http://www.eng.auburn.edu/research/centers/ncat/

Internationa Center for Aggregate Research (ICAR): http://www.icar.utexas.edu/

Texas Transportation Institute: http://tti.tamu.edu/