This project upgraded the Great Western Highway from two lanes to four lanes between Leura and Katoomba in the Blue Mountains. Spackman Mossop Michaels was commissioned by the RTA to develop the masterplan and conceptual design, to detailed design and construction documents over a period of ten years. SMM ensured landscape architecture was integrated with all aspects of the engineering design, resulting in a highway that respects the considerable natural, historic, and cultural values of the site, while also satisfying strict operational and safety requirements.