The present serviceability index (PSI) is a pavement performance measure. Introduced by the American Association of State Highway and Transportation Officials (AASHTO), the PSI is one of the most widely used pavement performance indicators after pavement condition index (PCI) and international roughness index (IRI).[1][2] This performance indicator ranges between 0 and 5, 0 representing a failed pavement and 5 an excellent one. Since the PSI entails slope variance, it is correlated with performance indicators related to roughness such as IRI.[3]


The PSI was developed based on the AASHO Road Test's present serviceability rating (PSR). AASHO Road Test was a set of experiments carried out by the AASHTO from 1956 to 1961.[4] Unlike the PSR, which was a ride quality rating that required a panel of observers to ride in a car over the pavement of interest, the PSI does not require a panel of experts. Therefore, it was a more practical approach for large-scale pavement networks.


Present serviceability is a function of several variables. For flexible pavement these variables include:[5]


  1. ^ Piryonesi, S. M.; El-Diraby, T. E. (2020) [Published online December 21, 2019]. "Data Analytics in Asset Management: Cost-Effective Prediction of the Pavement Condition Index". Journal of Infrastructure Systems. 26 (1): 04019036. doi:10.1061/(ASCE)IS.1943-555X.0000512. S2CID 213782055.
  2. ^ Piryonesi, S. M. (2019). The Application of Data Analytics to Asset Management: Deterioration and Climate Change Adaptation in Ontario Roads (Doctoral dissertation). University of Toronto.
  3. ^ Hall, Kathleen; Muñoz, Carlos (1999-01-01). "Estimation of Present Serviceability Index from International Roughness Index". Transportation Research Record. 1655: 93–99. doi:10.3141/1655-13. S2CID 108511635.
  4. ^ Transportation Research Board (July 2007). "Pavement Lessons Learned from the AASHO Road Test and Performance of the Interstate Highway System" (PDF). Washington DC: Transportation Research Board.
  5. ^ Cary, W. N.; Irick, P. E. (1960). "The pavement serviceability-performance concept" (PDF). Transportation Research Board.