NOTES: Road condition ratings are reported using the International Roughness Index (IRI) and the Present Serviceability Rating (PSR). States are required to report to the Federal Highway Administration (FHWA) IRI data for the Interstates, other principal arterials, rural minor arterials, and the National Highway System regardless of functional system. The IRI is also recommended by FHWA for measuring all other functional classifications because the IRI uses a more standardized and objective measurement methodology. Some States elect to report PSR for some sections of rural major collectors, urban minor arterials, and urban collectors. Pavement rating data are not reported for local or rural minor collector functional systems.

According to the pavement condition criteria used in the Highway Performance Monitoring System, an IRI rating less than 95 or a PSR rating greater than or equal to 3.5 indicates "good" ride quality. An IRI rating of less than or equal to 170 or a PSR rating for greater than or equal to 2.5 indicates "acceptable" ride quality. For further information, refer to the U.S. Department of Tansportation, Federal Highway Administration, 2008 Status of the Nation's Highways, Bridges, and Transit: Conditions and Performance Report, Exhibit 3-1, available at http://www.fhwa.dot.gov/policy/2008cpr/ as of January 2012.

SOURCE: U.S. Department of Transportation, Federal Highway Administration, Highway Statistics 2009, HM-63 and HM-64, available at http://www.fhwa.dot.gov/policyinformation/statistics.cfm as of March 8, 2012.