Describes various SHRP researchers' key findings, with emphasis on those fundamental chemical and physical properties of the binder that relate to its susceptibility to various distresses. Consideration and evaluation of the polar and non-polar molecules assists in understanding the performance of a given asphalt. The polars largely dictate the ability of an asphalt to resist permanent deformation. Low temperature cracking and fatigue cracking are largely influenced by the non-polar fraction. The impact of aging and asphalt compatibility on these distress modes is also discussed.