Comparing dynamic road wear of a performance-based standards and baseline vehicle

Abstract

The paved road network is a critical asset to any country and its economy. South Africa's paved road network has an estimated value in excess of R2 trillion. This asset is threatened by a backlog in maintenance of more than R416.6 billion, estimated in 2018. Overloaded heavy vehicles can cause more than 60% of the road wear on a road network. Most road wear analysis methods use static axle loads that are assumed to be symmetrical on either side of the road. Generally, Performance-based standards (PBS) vehicles have been shown to cause less road wear per tonne of payload compared to baseline vehicles when an assessment based on static axle loads is conducted. In this study, the dynamic road wear effects and the effects of road crossfall are studied in a road wear comparison of a PBS side tipper with a baseline vehicle. The results show that the PBS side tipper vehicle produces less road wear per tonne of payload when considering the first and fourth order aggregate tyre damage criteria for 0% and 3% crossfall. The road wear saving for fourth order aggregate tyre damage criteria for the left and right side was 10% and 11.5% at 0% crossfall and 5.7% and 11.3% at 3% crossfall. The results from the aggregate fourth order tyre damage and that from the mechanistic-empirical methodology produced similar results and indicate that the aggregate tyre damage criteria could be used for assessing PBS and baseline vehicle dynamic road damage. The study supports previous research that crossfall has a substantial influence on road damage of the left and right side of a vehicle. The maximum difference in the left and right side dynamic fourth order aggregate tyre damage was 32% for the baseline vehicle and 38% for the PBS vehicle.