This study used the HDM-4 software to test the average annual daily traffic (AADT) and equivalent single axle load (ESAL) levels appropriate as criteria for selecting the application of bituminous surface treatments (BST) to WSDOT pavements. It verified the feasibility of using BSTs to maintain pavements with higher traffic levels than have been applied in the past. It also determined the validity of alternating the application of BST resurfacings and 45-mm hot mix asphalt overlays. In addition, the research estimated the impacts that increased use of BST surfaces would have on the performance of the state-owned route system.
The basic recommendations are as follows:
This report is the first of two planned for the study.