NOTE FOR DATA ON THIS PAGE: Road condition is based
on measured pavement roughness using the International Roughness Index (IRI).
IRI is a measure of surface condition. A comprehensive measure of pavement
condition would require data on other pavement distresses such as rutting, cracking,
and faulting.
SOURCE FOR DATA ON THIS PAGE: U.S. Department
of Transportation, Federal Highway Administration, Highway Statistics,
Washington, DC: annual editions, tables HM-63 and HM-64, available at http://www.fhwa.dot.gov/
as of Feb. 1, 2002