Speed prediction models for heavy passenger vehicles on rural highways based on an instrumented vehicle study

Abstract

This study developed operating speed prediction models on tangents, curves, and tangent-to-curve transitions for heavy passenger vehicles (HPVs), using continuous speed profiles. Continuous speed profile data for HPVs were collected on two-lane rural highway sections, spanning a total length of 77 km. The curve radius, degree of curve, and preceding tangent length were found to be the influencing variables in predicting both the operating speed on the horizontal curves and the operating speed differential from tangent-to-curve transitions. The study also modeled the relationship between the differential of the 85th percentile operating speed (Δ⁢𝑉85) and 85th percentile operating speed differential (Δ85⁢𝑉). The analysis results from empirical data revealed that Δ⁢𝑉85 underestimates Δ85⁢𝑉 by 5.01 km/h. The reliability of the developed models was validated and compared with existing models from literature. The study highlights the significance of using continuous speed profile data to calibrate the operating speed models.