Road wear and tear increases as the fourth power of axle load. Are you counting the spending on bus stops, bus parking, dedicated bus lanes, and more on the other side of the ledger?

In FY25, according to their budget [1], TriMet - the Portland public transit authority - spent $19M on bus services.

In that same budget, PDOT spent $56M on streets, signs and streetlights, before you even consider the $242M spent on "asset management" - which appears to generally be capital improvements; i.e., rebuilding roads [2, page 509].

I don't care what fraction of that wear and tear is due to buses, it's not remotely close. And in any case, by the same fourth-power law, private 18-wheelers do astronomically more damage than buses.

And yes, PDOT makes revenue back from some of those things, so it's not all straight from the city general fund, but it doesn't matter in any practical way. They don't have revenues broken down as far as I'd like on that budget - there's one big $89M line item for "charges for services", which appears to include parking meters as well as tram fare - but the vast majority of their budget still comes from taxes plus "intergovernmental" sources (aka state and federal money, aka taxes).

[1] https://www.gpmetro.org/wp-content/uploads/2025/01/2025-Oper... [2] https://www.portland.gov/budget/documents/fy-2025-26-city-po...