When a pavement section is subjected to preservation or rehabilitation treatment, its surface condition is transformed from one set of condition states—those before treatment—to another set—those after treatment. This transformation is a function of the pavement condition before treatment, the type and timing of treatment, the project boundaries, and the quality of construction. For most pavement sections, the surface condition before and after treatment varies substantially along the section and over time. This study sponsored by FHWA analyzed the distribution of pavement surface condition and distress before and after treatment along several flexible pavement projects in the state of Louisiana. The study showed that current practices regarding the selection of pavement treatment type, treatment time, and project boundaries were independent of pavement surface condition and distress before treatment. For all pavement projects that received certain types of treatment in the past, knowledge of the relationships between the before- and after-treatment distributions of the pavement's surface condition and distress was crucial to the establishment of a future cost-effective strategy for pavement treatment. This paper shows that such relationships can be expressed by the probabilities of transforming before-treatment condition states to after-treatment condition states. These probabilities can be housed in one matrix format called the treatment transition matrix (TTM). For each treatment type, the TTM presents a snapshot of the state of the practice.