The impact of road geometry, surface roughness and truck weight on operating speed of logging trucks

Improved transport planning and pricing is dependent on correct cycle times. The objective of this study was to quantify the effect of road curvature, surface roughness, gradient and truck weight on the operating speed of a conventional 60-tonne gross vehicle weight logging truck. The study used a 320-km test track consisting of both public and forest roads. The track was driven with various gross vehicle weights. Speed data was retrieved from the truck's CAN-bus system and road data was measured with a profilograph. The key factors for operating speed were curvature and surface roughness, both of which were correlated to each other as well as partially captured by functional road class. Regression analysis quantified the individual effects of these factors as well as gradient, undulation and interactions with truck weight. A regression model is presented which explained 80% of the variation in operating speed. The results were consistent with previous studies, and the proposed models can be used to improve transport planning, cost estimation, operative route path selection and road investments.