In the US, road tolling and congestion pricing is not REALLY about congestion (or emissions).
Matt Rosenberg explains why Wyoming, the least congested state in the union, needs tolling.
And US DoT Secretary Lahood explains Highway Trust Fund 101 to the 400M transportation experts who live in the United States.
And here, above, from the Secretary's handy notes, you can see not only a picture of what running out of money looks like, but how the picture has gotten worse a little each year over the four years shown. It is this year-over-year decline that is at issue, not the spot fixes of last year and the one required again this that are the issue. Those are just $8B symptoms.
Its payback time.