The ASTM D7869-17 standard specifies implementing procedures for Xenon-arc exposure testing for enhanced light and water exposure for transportation coatings. This test procedure is designed to simulate the physical and environmental stresses faced by coatings in subtropical climatic conditions, such as southern Florida, such as high-intensity solar radiation, prolonged water exposure, and wet/dry cycles. These environmental conditions have been found to specifically lead to severe degradation of coatings, particularly for transportation vehicles such as automobiles. The development of this standard fills gaps in historical test methods and was developed through collaborative research between automotive and aerospace OEMs, material suppliers, and test equipment manufacturers for up to eight years. The use of this method helps evaluate the weathering performance of coatings in practical transportation applications and ensures that they meet safety and functional requirements.