Pavement performance can be represented either in load domain or time domain plots. The shape characteristics of pavement performance curves in the two types of plot are not the same. Plotting pavement performance in time domain is a useful form of representation for analysis in pavement maintenance management and life-cycle costs study. This paper examines the shape characteristics of pavement performance plots using the relationships developed in the AASHO (American Association of State Highway Officials) Road Test. It is illustrated that pavement performance curves in time domain can have different shapes depending upon the structural characteristics of pavement and the growth pattern of traffic load applications. Much wider variations in the shape characteristics of in-service pavement performance curves are expected due to the differences in the impacts of environmental factors, material aging, pavement maintenance effects, and changes in the rate of traffic load applications.