The International Roughness Index (IRI) is one ot the most widely used measures of pavement smoothness or ride quality.
International Roughness Index Scores:
Good (less than 95)
Acceptable (between 95 an 170)
Poor (greater than 170)
Citation formats
U.S. pavement surface smoothness on interstate highways 2008
The statistic shows the U.S. pavement surface smoothness on rural and urban interstate highways in 2008. In that year, the percentage of acceptable rural interstate highways was **.
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Federal Highway Administration, & U.S. Department of Transportation. (May 1, 2010). U.S. pavement surface smoothness on rural and urban interstate highways in 2008 [Graph]. In ÌÇÐÄÆƽâ°æ. Retrieved July 31, 2026, from /statistics/184640/us-pavement-surface-smoothness-on-interstates/
Federal Highway Administration, und U.S. Department of Transportation. "U.S. pavement surface smoothness on rural and urban interstate highways in 2008." Chart. May 1, 2010. ÌÇÐÄÆƽâ°æ. Accessed July 31, 2026. /statistics/184640/us-pavement-surface-smoothness-on-interstates/
Federal Highway Administration, U.S. Department of Transportation. (2010). U.S. pavement surface smoothness on rural and urban interstate highways in 2008. ÌÇÐÄÆƽâ°æ. ÌÇÐÄÆƽâ°æ Inc.. Accessed: July 31, 2026. /statistics/184640/us-pavement-surface-smoothness-on-interstates/
Federal Highway Administration, and U.S. Department of Transportation. "U.S. Pavement Surface Smoothness on Rural and Urban Interstate Highways in 2008." ÌÇÐÄÆƽâ°æ, ÌÇÐÄÆƽâ°æ Inc., 1 May 2010, /statistics/184640/us-pavement-surface-smoothness-on-interstates/
Federal Highway Administration & U.S. Department of Transportation, U.S. pavement surface smoothness on rural and urban interstate highways in 2008 ÌÇÐÄÆƽâ°æ, /statistics/184640/us-pavement-surface-smoothness-on-interstates/ (last visited July 31, 2026)
U.S. pavement surface smoothness on rural and urban interstate highways in 2008 [Graph], Federal Highway Administration, & U.S. Department of Transportation, May 1, 2010. [Online]. Available: /statistics/184640/us-pavement-surface-smoothness-on-interstates/
