SOURCE
U.S. Department of Transportation, Federal Highway Administration, Highway Statistics 2003, Washington, DC: 2004

DEFINITION
Roads with a very good condition rating. 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.

DEFINITION: Roads with a very good condition rating. 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.

SOURCE: U.S. Department of Transportation, Federal Highway Administration, Highway Statistics 2003, Washington, DC: 2004