The Tonkin Highway Extension proposal involves the construction of a 14 km extension of the Tonkin Highway from Thomas Road to the South Western Highway. It is intended to improve access to the south-eastern suburbs, reduce travel times, improve travel efficiency and improve safety.

We have evaluated the business case in accordance with the revised Statement of Expectations of 20 December 2020, which requires Infrastructure Australia to evaluate project proposals that are nationally significant or where Australian Government funding of $250 million or more is sought. The Tonkin Highway Extension – Thomas Road to South Western Highway proposal is subject to an Australian Government funding commitment of $404 million.

This proposal was accepted for evaluation 16 April 2021. 'As this proposal is already funded, our evaluation summary focuses on identifying delivery risks and opportunities to realise project benefits.