Analysis of the road–vehicle interaction: implications for force variability and pavement design

Understanding traffic load variability is essential in pavement design, as its effects stress and strain calculations. Traditional mechanistic pavement design methods use static standard loads, while advanced approaches include axle-load spectrum data and configurations. However, these methods overlook vehicle-pavement interaction. This study proposes a methodology to characterise its effect on pavement response. We show that simplified equations relate force variability to road roughness, offering a practical design and management tool. Previously, traditional methods focused on static loads and did not account for dynamic interactions. Our results reveal that pavement dynamic forces, influenced by road roughness and vehicle speed, follow a distribution, with variability increasing significantly with higher roughness and speed. The study highlights the chaotic response of steel suspension systems, especially at low damping, underscoring the need to consider vehicle suspension characteristics in pavement design. Additionally, maintaining low road roughness is critical for reducing force variability, suggesting that effective maintenance strategies are vital for road safety and durability. Our findings provide a framework for understanding and managing pavement force variability, emphasising the importance of incorporating dynamic analyses into pavement design. This broader perspective enhances road infrastructure reliability and longevity, improving transportation safety and efficiency.