#### § 490.305 Definitions.

The following definitions are only applicable to this subpart, unless otherwise provided:

*Asphalt pavements* means pavements where the top-most surface is constructed with asphalt materials. These pavements are coded in the HPMS as having any one of the following Surface Types:

| Code | Surface__type |
| --- | --- |
| 2 | Bituminous. |
| 6 | Asphalt-Concrete (AC) Overlay over Existing AC Pavement. |
| 7 | AC Overlay over Existing Jointed Concrete Pavement. |
| 8 | AC (Bituminous Overlay over Existing CRCP). |

*Continuously Reinforced Concrete Pavements (CRCP)* means pavements where the top-most surface is constructed of reinforced Portland cement concrete with no joints. These pavements are coded in the HPMS as having the following Surface Type:

| Code | Surface__type |
| --- | --- |
| 5 | CRCP—Continuously Reinforced Concrete Pavement. |

*Cracking* means an unintentional break in the continuous surface of a pavement.

*Cracking Percent* means the percentage of pavement surface exhibiting cracking as follows:

(1) For asphalt pavements, Cracking Percent is the percentage of the area of the pavement section, exhibiting visible cracking.

(2) For jointed concrete pavements, Cracking Percent is the percentage of concrete slabs exhibiting cracking.

(3) For CRCP, the Cracking Percent is the percentage of pavement surface with longitudinal cracking and/or punchouts, spalling or other visible defects.

*Faulting* means a vertical misalignment of pavement joints in Portland Cement Concrete Pavements.

*International Roughness Index (IRI)* means a statistic used to estimate the amount of roughness in a measured longitudinal profile. The IRI is computed from a single longitudinal profile using a quarter-car simulation, as described in the report: “On the Calculation of IRI from Longitudinal Road Profile” (Sayers, M.W., Transportation Research Board 1501, Transportation Research Board, Washington, DC 1995).

*Jointed concrete pavements* means pavements where the top-most surface is constructed of Portland cement concrete with joints. It may be constructed of either reinforced or unreinforced (plain) concrete. It is coded in the HPMS as having any one of the following Surface Types:

| Code | Surface__type |
| --- | --- |
| 3 | Jointed Plain Concrete Pavement (includes whitetopping). |
| 4 | Jointed Reinforced Concrete Pavement (includes whitetopping). |
| 9 | Unbonded Jointed Concrete Overlay on PCC Pavement. |
| 10 | Bonded PCC Overlay on PCC Pavement. |

*Pavement* means any hard surfaced travel lanes of any highway.

*Pavement section* means a nominally 0.1 mile-long reported segment that defines the limits of pavement condition metrics required by FHWA.

*Present Serviceability Rating (PSR)* means an observation based system used to rate pavements.

*Punchout* means a distress specific to CRCP described as the area between two closely spaced transverse cracks and between a short longitudinal crack and the edge of the pavement (or a longitudinal joint) that is breaking up, spalling, or faulting.

*Rutting* means longitudinal surface depressions in the pavement derived from measurements of a profile transverse to the path of travel on a highway lane. It may have associated transverse displacement.

*Sampling* as applied to pavements, means measuring pavement conditions on a short section of pavement as a statistical representation for the entire section. Sampling is not to be used to measure or rate NHS pavement conditions.