The application of elastic theory to the design of overlays on existing pavement requires that a modulus of elasticity be assigned to the existing structural system. Estimates of elastic modulus are obtained from dynamic deflection reading in the field; but asphalt is a highly temperature-sensitive visco-elastic material and deflections not corrected to a standard temperature can produce misleading results. It is therefore the objective of the present study to develop a procedure for estimating an effective modulus of elasticity for a layer of asphaltic concrete in which some temperature gradient exists because of the combined influences of solar radiation, wind, air temperature, cloud cover and other variables specific to time and location which cause temperature variation within the pavement layer. Two models are presented from the achievement of that objective.