EXSPAV is an expert system program established for use in flexible pavement and overlay design. It helps transfer and facilitate the knowledge of experts and results of research and practice to the hands of the less experienced design engineer. It incorporates a versatile design approach, which also facilitates the prediction of the structural performance of pavements. EXSPAV was developed in the EXSYS environment and assimilates Ohio State University's predictive program of flexible pavement structural performance. It also has an overlay design module. EGYPAV is a knowledge-based pavement design program developed in the structure of EXSPAV. Its knowledge base was compiled through consultation with experts from the Roads and Bridges Authority, local universities, and construction companies. The base reflects experience, data, and research results for traffic, environmental conditions, pavements, and material characterization in Egypt. It also includes suggested designs of pavement structure for various combinations of design parameters. The program user may check the suggested design and find its structural performance through the inference engine–deterministic model interaction of the EGYPAV itself.