The main objectives of this study are to develop the relationship between initial IRI and network IRI and to predict service lives of pavements. The raw data used in this research, including IRI, pavement ages, Annual Average Daily Traffic (AADT), and locations of pavements, were provided by North Carolina Department of Transportation (NCDOT). The raw data were merged, linear regression, analysis of variance (ANOVA), and contrasts were conducted to investigate the relationship, and to estimate pavements' service lives. The conclusions revealed that pavements with smaller initial IRI last longer, and that average service lives after construction and treatments for US, NC, and the SR roadways are 16.4, 9.5, and 6.7 years, respectively.
