In 2025, TriMet had 262 million passenger miles at a system cost of $812 million, for a cost of $3.09 per passenger mile.[1] Fares covered 7.8% of their costs. The other 92.2% came from payroll taxes and federal grants.

For comparison, a Lyft or Uber in the same area would cost you $1-2 per mile. Obviously it's not feasible for all 200k daily riders to take Uber/Lyft, and the Uber/Lyft cost doesn't include externalities like extra traffic, but TriMet is very expensive per passenger mile.

1. https://trimet.org/about/pdf/trimetridership.pdf

The cost of providing a bus exceeds the cost of operating a car in many cases, like lower population density neighborhoods. It may save the public money to centralize transit on major corridors and then subsidize trips on Waymo in some areas and at some times.

If it can deliver transit to the public at a reasonable price…

At the margin, it substitutes for some trips.