ISO 13473-4:2024

Overview - ISO 13473-4:2024 (One‑third‑octave band spectral analysis of surface profiles)

ISO 13473-4:2024 specifies standardized methods to perform spectral analysis of pavement surface profiles, producing spatial frequency (or texture wavelength) spectra in octave and one‑third‑octave constant‑percentage bandwidths. It applies to two‑dimensional surface profiles (texture amplitude versus distance along a straight or curved trajectory) measured with profilometers. The standard defines a normative digital‑filtering method for constant‑percentage bandwidth analysis and describes an informative DFT‑based alternative (discrete Fourier transform followed by conversion to octave bands). Results are expressed as power spectral density (PSD) or texture profile levels for specified centre wavelengths.

Key technical topics and requirements

• Analysis methods
  • Normative: digital filtering to obtain octave / one‑third‑octave band spectra (constant‑percentage bandwidth).
  • Informative: narrow‑band DFT followed by transformation to octave bands (non‑preferred).
• Input data pre‑processing
  • Requirements for profilometers and data quality (see ISO 13473-3).
  • Sampling interval, resampling to constant spatial resolution, anti‑aliasing filtering.
  • Drop‑out detection, interpolation, spike identification/removal and profile conditioning (normative annexes).
• Spectral definitions
  • Spatial frequency (cycles per metre) and texture wavelength (reciprocal of spatial frequency) representation.
  • Power spectral density (PSD) units and interpretation; texture profile levels on logarithmic scale.
• Uncertainty and reporting
  • Procedures for estimating uncertainty of spectral results (normative Annex A).
  • Standardized reporting formats and requirements for reproducibility.
• Limitations
  • PSD does not capture profile asymmetry (positive vs negative features); see informative Annex B.

Practical applications and users

Who uses ISO 13473-4:2024:

• Road and pavement engineers performing texture characterization and QA
• Acoustic and tyre‑road noise modelers using texture spectra as input
• Friction and skid resistance researchers (texture affects friction, rolling resistance, tyre wear)
• Profilometer manufacturers and instrumentation laboratories validating processing chains
• Agencies specifying surface texture requirements for construction and maintenance

Practical uses:

• Quantifying texture content by wavelength bands for noise prediction and mitigation
• Comparing pavement surfaces, tracking condition changes, and acceptance testing
• Feeding texture spectra into vehicle/tyre simulation and acoustic models
• Standardizing data processing for multi‑device or multi‑laboratory studies

Related standards

• ISO 13473-2 - Terminology and basic requirements for texture profile analysis
• ISO 13473-3 - Specification and classification of profilometers (measurement devices)
• IEC 61260-1 - Octave and fractional‑octave filter specifications (relevant filter parameters)
• ISO/IEC Guide 98-3 (GUM) - Guide to expression of measurement uncertainty

Keywords: ISO 13473-4:2024, pavement texture, surface profiles, one‑third‑octave band, spectral analysis, spatial frequency, texture wavelength, PSD, digital filtering, DFT, profilometer.