Sowmya, N.J.Ravi Shankar, A.U.Anjaneyulu, M.V.L.R.2026-02-052012International Journal of Earth Sciences and Engineering, 2012, 5, 5, pp. 1408-14149745904https://idr.nitk.ac.in/handle/123456789/26916Geometric design elements play an important role in defining the operational efficiency of any roadways. Considerable research has been undertaken worldwide to explore the design consistency concept including identifying potential consistency measures and developing models to estimate them. The main objective of this study is to investigate the design consistency of intermediate lane highways existing in Dakshina Kannada district of Karnataka state based on operating speed and speed differential models. The speed measurements are taken at the mid of tangent section and start of the curve during daylight, off-peak periods and under dry weather conditions. The multiple linear regression analysis technique in SPSS (Statistical Package for Social Sciences) software is used for model estimation. Both operating speed (85th percentile speed) and 85th percentile speed differential measures are used with geometric data to identify the design consistency of horizontal curves. A comparative study is performed to identify the variation between these two speed measures. Operating speed and speed differential models for intermediate lane rural roads are presented in this paper. © 2012 CAFET-INNOVA TECHNICAL SOCIETY.Comparative studiesConsistency measuresDesign consistencyDry weathersGeometric dataGeometric designHorizontal curvesKarnatakaModel estimationMultiple linear regression analysisOff-peak periodsOperating speedOperational efficienciesSpeed differentialSpeed measurementStatistical packagesDesignLinear regressionRural roadsSocial sciences computingSpeedcomparative studydesignmultiple regressionroadrural areasoftwarevelocityDakshina KannadaIndia