The Great Western Highway Upgrade Program from Katoomba to Lithgow aims to provide safer, more efficient, more reliable journeys, and better connect communities with the Central West. This area includes the World Heritage Listed Blue Mountains National Park, significant freight movements from the Central West and Orana Region (including Dubbo) and one of the top 5% most disadvantaged areas in Australia (Lithgow). There are frequent truck breakdowns on the steep Mt Victoria section, which has limited overtaking options, and significant traffic delays on weekends and during peak tourism seasons. The alternative Bells Line of Road also has frequent closures and incidents. 

A program-wide Strategic Business Case considered alternative road widening and tunnel options, as well as demonstrating overall value for money for the program. This included estimation of benefits from improved reliability, safety and resilience to incidents; enabling high productivity freight vehicles; induced freight; induced tourism; and regional access to healthcare and higher education. Final Business Cases were also prepared for the East/West Sections (road widening) and Central Section (11km tunnel). 

Our people’s involvement

Members of our team managed the transport demand modelling and economic appraisal workstreams and were client-side advisors for the Strategic and Final Business Cases. This included leading Infrastructure Australia assurance responses, social value assessment, resourcing strategy, prioritising sustainability initiatives and a construction workforce housing assessment (including feasibility modelling of alternative development sites). 

The demand modelling and economics challenges for this program were extensive and complex. Transport modelling included both a mesoscopic model of the corridor and a state-wide strategic model. The economic appraisal was also supplemented with a Computable General Equilibrium (CGE) model of the economy, a land use transport interaction (LUTI) model and hedonic pricing model of land values. 

As part of the social value assessment, our team members developed a new approach to estimate social benefits from improved regional access to healthcare and higher education to supplement the conventional economic appraisal. These were significant, estimated to be in excess of $500 million (present value). 

Key achievements and value-add 

• Successful Investment NSW and Infrastructure Australia assurance securing more than $2.5 billion in funding

• Social value approach presented at the Australasian Transport Research Forum 2021 and published.