Re: It ain't all about poor cities and states
"If it says I-280, it should be free."
Note to anyone visiting the SF Bay Area: Interstate 280 is NOT free, in fact it cost us tax payers quite a bit of money. However, there is NOT a per-use fee, so don't expect to find toll booths.
OP may have been referring to one of the other three I-280s (New Jersey, Ohio, or Illinois-Iowa). The three-digit Interstate numbers are not unique, and since I-80 runs coast-to-coast, there are plenty of I-x80 roads.
There are also two roads that used to be I-280s but were renumbered, according to Wikipedia.
In any case, I'm not sure what OP's point about the Federal Interstate system was supposed to be. The Interstate system is a collection of Federally-subsidized, limited-access, multilane highways. They're "Interstate" because they're supposed to facilitate interstate commerce, which is why there are Interstate highways even in both isolated states (that one in the middle of the Pacific and the one you can see from Russia), and even major (two-digit) Interstates in the Contiguous 48 that are confined to one state.1
There's nothing about the Interstate system that says states aren't supposed to be able to impose additional per-vehicle fees. The Feds subsidize Interstates - they don't pay the whole cost. Many Interstates in the eastern half of the country have tolls, including the Big One, I-90, much of which is tolled east of Wisconsin.
Offhand, the westernmost Interstate toll I can think of is I-70 outside Topeka, Kansas.
In any case, though, while I can appreciate that many people don't like toll roads, I can't see how this is specifically the violation of some compact, explicit or implied, between the government and the people. Indeed, I can't help but feel it makes a certain amount of sense to have road users pay a greater proportion of the cost of road maintenance. (I know, money is fungible and tolls only notionally go toward paying for roads. Still, this means people who drive on toll roads throw a few extra pennies in the pot.)
1OK, I may be exaggerating a bit, since the one I'm thinking of actually extends over two miles into a second state, and I don't have another example in mind. But close enough.