Table 1-4: Road Condition: 2008

(Miles)

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NOTES: Road condition ratings are derived from 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 Interstate system, 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. However, where PSR is still in use, the mileage for the PSR and IRI are combined for purposes of this table. Pavement rating data are not reported for local or rural minor collector functional systems.

The road condition rating system is as follows: Urban and rural interstates are rated with IRI only. Very good = <60; Good = 60-94; Fair = 95-119; Mediocre = 120-170; Poor = 171->220. Interstates have stricter roughness standards than other roads and its roughness classifications are not comparable with the other categories. Rural minor and other principial arterial roads, urban other freeways and expressways, and urban other principal arterial roads also use IRI only. Very good = <60; Good = 60-94, Fair = 95-170; Mediocre = 171-220; Poor = >220. Rural major collector, urban minor arterial, and urban collector roads use a combination of IRI and PSR, by adding corresponding mileage evaluated under both systems. Very good = <60 plus >3.9; Good = 60-94 plus 3.5-3.9; Fair = 95-170 plus 2.6-3.4; Mediocre = 171-220 plus 2.1-2.5; and Poor = >220 plus <2.0. For further information, refer to the U.S. Department of Transportation, FHWA, Status of the Nation's Highways, Bridges, and Transit: 2002 Conditions and Performance Report, Exhibit 3-3, available at http://www.fhwa.dot.gov/policy, as of April 2010.

SOURCE: U.S. Department of Transportation, Federal Highway Administration, Highway Statistics 2008, Washington, DC: 2009, tables HM-63 and HM-64, available at http://www.fhwa.dot.gov/policy/ohpi/hss/hsspubs.cfm as of Apr. 2, 2010.