The 0.45 Power Curve Void Prediction Method and the Coarseness Factor Method were tested using thirty six combined aggregate gradations, most meeting KDOT gradation standards. The 0.45 Power Curve Void Prediction Method yields more consistent predictions of percent voids in combined aggregate than the Coarseness Factor Void Prediction Method. The Coarseness Factor Method requires less calibration and physical testing than the 0.45 Power Curve Void Prediction Method. Neither the 0.45 Power Curve nor the Coarseness Factor Void Prediction Method are accurate for combined aggregate that deviates substantially – more than 15% on an individual sieve size – from the 0.45 maximum density line. Well-graded aggregate showed less estimation error than aggregate that was not well-graded using the coarseness factor void prediction method.