It is really getting hard to believe that with all of of the criticism of the flat-rate London Congestion Charge – by advocates of congestion pricing, no less – and all of the talk of VMT-pricing  in the United States (which hopefully is TDP-pricing  by the wrong name), that intelligent people keep coming up with cockamamie flat rate schemes.
In San Francisco, 'congestion pricing' is something they're sneezing at.
California Dreaming: Even In San Francisco, People Don’t Want to Pay to Drive Downtown.
It flopped in NYC. I predict (and so do you!) that it will flop in San Francisco.
Charging a fixed fee is always economically inefficient. Whether you pay $6 or $20, once paid you have no incentive to drive less or differently. This is also unfair to those who do drive less. If Mary drives 13 miles in the zone, and Susan drives two, why should they both pay the same? For the same reason that all-you-can-eat diners gets fat, all-you-can-drive-cities get congested, we see that in London already. The London Congestion Charge may be well meaning, but it is wrong headed. Stop admiring it. The point has been made. Move on. Pay for exactly and only for what you use. Demand variable TDP-pricing in place of the gas-tax. Its fairer and more effective. And it can actually cost less and be anonymous (now those are nice surprises).
BUT some good news, here, Oregon seems to get it, and they're not all that far away from California. How come? What makes it worse is that tons of money were spent to discover what the Governor of Oregon now knows. Can somebody call someone in San Francisco please?
 Vehicle-Miles Traveled;  Time-Distance-Place