Moisture damage is a common problem faced by highway agencies. Researchers have developed laboratory test methods over the years to identify moisture-susceptible asphalt concrete mixtures, but none of them has been consistently successful. A new laboratory test method, the Environmental Conditioning System, was developed under the Strategic Highway Research Program. This new test method has a distinct advantage over the existing methods because it can simulate field conditions. However, a comprehensive evaluation of the method showed that although it is a promising concept, it needs further modification and evaluation. In this paper, several modifications to the original Environmental Conditioning System are proposed. The results from a preliminary evaluation of the system are also included. The new system has been able to identify poor and marginally performing mixtures.