The share of state road surfaces that is classified as poor or very poor based on measurements of furrows (crosswise evenness) and lengthwise evenness (International Roughness Index &– IRI) on solid road surfaces. Poor road surfaces have a furrow depth of 18-24 mm or an IRI of 3.1-4.4 mm/m. Very poor road surfaces have a furrow depth of more than 24 mm or an IRI of more than 4.4 mm/m.