Transportation Research Record: Journal of the Transportation Research Board, No. 2223, Transportation Research Board of the National Academies, Washington, D.C., 2011, pp. 9–17. DOI: 10.3141/2223-02 Operating speed is most frequently represented by the 85th percentile speed (V85) of vehicles passing at a given road location, in a nonplatoon condition, and it is usually determined by spot speed...