ALTERNATIVE APPROACH TO ESTIMATION OF CRITICAL CORNERING SPEED

An alternative approach to the estimation of the critical cornering sp eed of large combination vehicles is presented. Existing techniques ar e based on analytical models subject to a series of simplifying assump tions, and do not explicitly consider grades and other three-dimension al roadway features of the real problem. One result of this study indi cates that these simplified models may overestimate critical cornering speed by as much as 50%. The proposed technique combines detailed sim ulation of the dynamics of the motion of large combination vehicles th rough a three-dimensional roadway, with a Monte Carlo sampling of poss ible vehicle configurations and component mechanical properties to pro duce databases for statistical analysis. This approach is applied to t he study of critical cornering speed at freeway-to-freeway connectors. Databases for several samples of vehicles are generated, and a series of regression models that predict critical cornering speed is created . Results indicate that these regression models may be used to predict critical cornering speed to a high degree of accuracy. Finally, criti cal cornering speeds estimated using these models compare reasonably w ith actual speed data collected at five freeway connectors.