The aim of the study was to investigate the real axle loads of roundwood transport vehicles resulting from the gross vehicle weight (GVW) of the transport unit in different seasons of the year and depending on the type of transport unit and the type of wood assortments. Measurements of axle loads for round wood trucks were carried out on the sites of three large wood industry companies from the north of Poland, which process different types of wood.

In total, measurements were made for 904 round wood deliveries, made by different transport sets: truck and trailer unit with 473 deliveries, including 344 deliveries by six-axle sets, truck and semi-trailer, 334 deliveries, where 193 was made by six-axle sets. The lowest axle load for all sets occurs on first axle in the range of average values of 7.07-7.86t with a spread of results from 4.49 to 10.20t. The highest average axle loads of 9.15-12.43t were found on second axle for all observed transport unit, where a maximum value of 14.52t was also found.

Statistically significant differences were found in the values of loads on individual axles depending on the type of truck unit and type of wood assortment. The distribution of the total gross vehicle weight of the set is on average 58-60% to the truck (three axles) and 40-42% to the trailer/semi-trailer (two axles) in five-axle sets, and in six-axle sets the truck and trailer/semi-trailer (three axles). The loads of transported wood (assortments) influence the resulting axle loads, which was confirmed by statistical analysis. For most axles there are differences in axle loads between transport units with MS (medium-size round wood, industrial wood) and the other wood assortments. Additionally on axles 4-5 there are differences between LS (large-size round wood) and the other loads (multiple mean rank test).