This paper presents a summary of the findings by SHRP Contractor A-003A (OSU) of an extensive study to validate the hypothesis of SHRP contractors A-002A and A-003B related to water sensitivity. For water sensitivity evaluation, an accelerated rutting test utilizing the LCPC Rutting Tester, herein referred to as the OSU wheel trackers, was selected as the primary method. However, tests on the same mixtures were also conducted using the wheel rutting tester at SWK/University of Nottingham (UK), herein referred to as the SWK/UN wheel tracker, the Environmental Conditioning System (ECS) developed at Oregon State University and the Net Adsorption Test (NAT) conducted by the University of Nevada-Reno. Each test procedure results in a different failure mechanism but all tests can be used to evaluate the water sensitivity of asphalt-aggregate mixtures.