What is BS EN 13036‑5- Longitudinal unevenness indices about?  
BS EN 13036‑5 specifies the mathematical processing of digitized longitudinal profile measurements to produce evenness indices.
The evenness range covered in BS EN 13036‑5 is defined as the wavelength range 0,5 m to 50 m. Note: It is noted that both shorter and longer wavelengths can also influence driving comfort but those are not covered in BS EN 13036‑5.
Note: BS EN 13036‑5 doesn’t define from what position on the road the longitudinal profile should be obtained.
Who is BS EN 13036‑5 for? 
BS EN 13036‑5 on the determination of longitudinal rail restraint is useful for: 
- Construction industry
- Civil engineers
- Airport authorities
- Road maintenance and management authorities
Why should you use BS EN 13036‑5?  
Through road/vehicle dynamic interaction and vehicle vibration, the road profile evenness affects safety (tire contact forces), ride quality, energy consumption, vehicle wear as well as pavement and road durability. The road profile evenness is thus of significance for road maintenance management- systems and performance control. 
The purpose of BS EN 13036‑5 is to provide a standard practice for calculating and reporting estimates of road evenness from digitized longitudinal profiles. 
BS EN 13036‑5 describes the calculation procedure for the International Roughness Index (IRI), Root Mean Square (RMS) and Longitudinal Profile Variance (LPV) from three separate wavelength bands and the σWLP and ΔWLP from the Weighted Longitudinal Profile (WLP).
The quantified evenness indices derived from BS EN 13036‑5 are useful support for pavement management systems. The output can also be used for type approval and performance control of new and old pavements. The indices can be used on rigid, flexible and gravel road surfaces.
Additionally, BS EN 13036‑5 also facilitates the comparison of evenness measurement results carried out with different profiling instruments in European countries.
