Analysis of vehicle operating costs and the relationship between haul road conditions and geometry and trailer operating speed in coal transportation at PT Adaro Indonesia

Coal transportation performance on haul roads is influenced by pavement surface conditions, road geometry, vehicle load characteristics, and operational regulations. This study aims to analyze the effects of the Road Condition Index (RCI), road grade, curves, load status, and speed limits on the operating speed of double-vessel trailers on the haul roads of PT Adaro Indonesia; identify the most dominant variable; and calculate Vehicle Operating Costs (VOC) as a supporting analysis. The data used include RCI assessments, operating speed data obtained from GPS, road grades, curve classifications, load status, speed limits, and vehicle cost data. The analysis was conducted using descriptive statistics and multiple linear regression with the assistance of SPSS. Based on 2,641 observations, the resulting regression equation was Speed = 26.147 + 3,844(RCI) – 0,928(Grade) – 5,906(Curve) – 7,802(Load) + 19,783(Speed Limit). The model has a correlation coefficient of R = 0,635 and a coefficient of determination of R² = 0,403, with a simultaneous significance value of 0,000. The operational speed limit is the most dominant variable, with a standardized beta coefficient of 0,519. The trailer VOC was calculated at IDR 45.361,86 per trailer-kilometer. These findings indicate that road conditions and operational factors are collectively associated with trailer operating speed, while speed limit management is the dominant factor in the model.