1.1 This practice is applicable to the processing of road surface profiles for the purpose of computing a single numerical index related to the roughness of a profile.

1.2 A data record of the surface profile, measured according to an applicable test method, is assumed. The data record may be a representation of either elevation, slope, or acceleration.

1.3 Procedures are defined for computing the index over the length of the profile record, or over specified sub-sections of the record.

1.4 This practice covers only the computation procedures and does not specify or define the form of the profile index weighting function except in the requirement that the index be expressed in the form of either a "mean square" or "root mean square" measure of the surface profile. The numerical value of the computed index will depend on the weighting and window functions used. The weighting function used can incorporate any linear mathematical operation, such as multiplication by a constant, differentiation, or integration. Measures obtained using nonlinear operations, such as rectification, are not covered.