FILTER EXPERIMENT - THEORETICAL STUDY OF INDICES

The FILTER (FEHRL Investigation on Longitudinal and Transverse Evenness of Roads) project was conducted to establish an inventory of all measuring devices and assessing methods used in Europe in order to harmonise the methods of measuring and assessing road evenness. This report compares the longitudinal data processing methods and studies the influence of measurement errors on the quantifiers. Twenty longitudinal indices were defined and common elements and differences between them are discussed. A method for creating artificial longitudinal profiles is outlined. The profiles were used to estimate the influence of different measurement parameters on the longitudinal indices. The effects of rut depth and water depth on errors of transverse indices are considered. It was concluded that all current longitudinal indices treat the reporting length as if it was homogeneous and do not identify singular irregularities.