How many years of free public transport would $22B buy?

I recall the 50% price cut during COVID (for the whole country) cost the government a few hundred million for a year. This was during COVID so it didn't get higher uptake, but let's assume there was a higher uptake and make it $500M for 50% off per year, or 1B for free public transport per year.

We could have free public transport for everyone for 22 years for the price of this one road.

How much is that per centimeter?

Is anybody held accountable or are there any incentive structures to prevent it from happening in the future?

I saw this recently

"Even so, the numbers are staggering. The section between Whangarei and Te Hana is expected to cost $15.3-18.3 billion, and this doesn’t include the cost of the Warkworth to Te Hana section which is expected to start construction next year and was most recently estimated to cost $2.9-3.8 billion.

Combined, that’s $18.2-22.1 billion – which is incredible for a road that for most of its length carries only 10-15,000 vehicles a day.

To put the cost a different way: if usage of the road more than doubled to 30k vehicles per day (which is more than most parts of the Waikato Expressway) over a 30 year span, that would still work out at nearly $70 per trip include the cost of operating and maintaining the road."

https://www.greaterauckland.org.nz/2025/10/21/rons-reality-needs-to-bite/