1. ASTM, Standard practice for computing international roughness index of roads from longitudinal profile measurements, ASTM Standards 04.03, Road and Paving Materials; Vehicle-Pavement Systems, E1926–98, 2005
2. CEN, Road and airfield surface characteristics—Test methods—Part 5: Determination of longitudinal unevenness indices (draft), European Standards, prEN 13036–5, 2006
3. Fundamentals of Vehicle Dynamics