1. American Society of Testing and Materials - ASTM E 1926 (2003). Standard Practice for Computing International Roughness Index of Roads from Longitudinal Profile Measurements. In Annual Book of ASTM Standards, West Conshokhocken, PA.
2. Amos, D. (2006). Pavement Smoothness and Fuel Efficiency: An Analysis of the Economic Dimensions of the Missouri Smooth Road Initiative. http://168.166.124.22/RDT/reports/Ri05040/or07005.pdf.
3. Bray, J. (2002). The Role of Crash Surveillance and Program Evaluation: NYSDOT's Skid Accident Reduction Program (SKARP). Presented at 28th International Forum on Traffic Records and Highway information Systems, Orlando, Florida.
4. Chang, J., Chang, K., & Chen, D. (2006). Application of 3D Laser Scanning on Measuring Pavement Roughness. Journal of Testing and Evaluation, 34.(2).
5. Chatti, K., & Zaabar, I. (2012). Models for Estimating the Effects of Pavement Conditions on Vehicle Operating Costs. National Cooperative Highway Research Program (NCHRP) Report 720, http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_720.pdf.