How Would We Know?

The absence of a publicly available cost benefit analysis for the proposed Bus and Train (BAT) Tunnel project in Brisbane raises a couple of obvious questions.  The first is the simplest.

The previous Cross River Rail (CRR) proposal was expected to cost around $6.4 billion to construct.  At this stage the BAT Tunnel is expected to cost around $5 billion.  Queenslanders save $1.4 billion right?

Financially they do.  But without a full CBA we cannot know what benefits are being left on the table.  If more than $1.4 billion in benefits under CRR are not realised in the BAT Tunnel we are actually reducing the net economic benefit of getting a decent public transport solution.

How would we know?

Valuing Toowoomba’s Second Range Crossing

What value can we put on the capital cost per vehicle using the $1.6 billion Toowoomba Second Range Crossing?

Let’s assume: in a 25 year appraisal period traffic volumes grow 3.5% p.a.; some 75% of some 23,000 vehicles per day divert to the crossing; and a 4% real discount rate. How does just under $12 a vehicle sound?

Bump traffic growth to 6% p.a., raise diversion to 85% diversion, and trim the discount rate to 3%, and you get just over $6.

Sets a bar, doesn’t it?

This project will only show a net economic benefit if benefits that are eventually identified are multiples of this.