Any project in a heavily regulated environment is not measurable that way. The cost comes from compliance, audits, paperwork. Trials, PoCs, etc. You also need to prove security and a long term lifecycle for the solution. Those open source packages - are they being updated? Who validates patches? etc etc. Those are moats, once you're able to deliver the above, you're set for a long time. Good luck!
At nearly 400,000 AUD per vehicle, the question should be what better opportunities to help people did the Australian Govt pass up in order to engage this project?