Development of lateral acceleration prediction models and consistency evaluation criteria for horizontal curves with gradient on two lane rural highways.

Abstract

Objectives: The challenge of combined horizontal and vertical highway alignments continues to be a concern in transportation design, particularly regarding truck stability. This study analyses the stability of trucks on horizontal curves combined with ascending or descending gradients using center of gravity (CoG) height and curve geometry as parameters. It also develops models that predict lateral stability of trucks and criteria for evaluating geometric design consistency based on vehicle stability.

Method: A smartphone application was used to collect real-time data on lateral acceleration experienced by two-axle trucks on curves with gradient.

Results: Findings show a lower safety margin against rollover on curves with descending gradient compared to ascending ones. Key factors affecting stability are identified as radius and length of horizontal curve, suggesting improvements in rollover stability by increasing these parameters. Geometric design consistency evaluation criteria were developed based on lateral acceleration, categorizing curves with gradient as good, fair, or poor. Predictive models were developed to quantify the impact of CoG height of truck and curve geometry on lateral acceleration, aiding in consistency assessment.

Conclusion: Outcomes of research will be useful for the design of safer horizontal curves with gradient by prioritizing vehicle stability.