The Port of Brisbane Motorway Upgrade project involves the construction of 6 km of new and duplicated motorway, delivered under a competitive double Early Contractor Involvement (dECI) model. The majority of the project is underlain by saturated soft soils up to 30 m deep, which presented various geotechnical challenges for performance of the road and interaction with fixed structures. A “tread lightly” observational risk based approach was adopted for the design and construction of embankments and ground improvement works. Initial settlement predictions were carried out using the Illicon procedure. Extensive instrumentation was installed, monitored and interpreted to provide improved post-construction settlement estimates.