This paper presents two test procedures, the constant load andhaversine load, for determining the viscoelastic properties ofasphalt concrete using the indirect tension (diametral compression)test. Equations for calculating the creep compliance and complexcompliance from test result are derived. Locations of change inlength measurements are recommended. Details of data reductionalgorithms and the pros and cons of the two procedures are discussed.A series of laboratory tests were conducted on two groups of specimensto illustrate the methodology and verify the analysis.