This project explores options to improve the drainage performance of open graded asphalt (OGA) wearing courses on the Western Australian road network. It focuses on understanding the limitations of current OGA systems—particularly on multi-lane freeways—and identifying opportunities to increase flow capacity and reduce the risk of surface water and aquaplaning.
The project will review current national and international practices and develop a shortlist of potential design and material solutions for further investigation. The outcomes may inform future research stages and support updates to specifications, design approaches and guidance for OGA surfacing systems.