Based upon the results of this tudy, the vacuum sealing method did provide an accurate estimation of bulk specific gravity. It was concluded that for lab prepared HMA samples having gradations passing above the maximum density line, the saturated surface dry test method provided accurate results for the air void content range encountered. However, the vacuum sealing method should be used for lab prepared HMA samples having gradations passing below the maximum density line. This included mix design samples. On average, the use of the vacuum sealing method during mix design would have resulted in the addition of about 0.2% more asphalt binder. For field compacted samples, it was concluded that the saturated surface dry method was adequate for HMA mixes having gradations more than 10% finer than the maximum density line on the 2.36 mm (no.8) sieve. The vacuum sealing method should be used on field compacted samples for all other gradation shapes