I personally don't know what to make of taxing you based on the miles you travel. From what I gather, though this is subject to change as I learn more about it... my first impression has been that everyone paying into a collective pool helps "Subsidize" our affordable way of life. Note that virtually all goods transported use the highway system, and even a majority of services use the highway system. Whether it be a hotel offering a shuttle to the airport, someone transporting beer from a local brewery, fedex ground delivering goods from SFO airport, or a truck carrying a shipment of TV's from the Port of Oakland to a Bestbuy distributor. By having a pool of people WHO ALL DEPEND on these goods and services either for a livelihood. Just because you can bike to work at your local whole foods grocer doesn't mean that you don't benefit from paying taxes into supporting and maintaining our roads.
My premature feelings on the issue is that this is a tax on productivity, and as always, the lower middle class and middle class who don't live in the city, and businesses are the one to take the boot whereas the liberals and the wealthy who live in the city and enjoy the subway and public transit options that taxes on those who drive provide. The city dwellers benefit the most from this, and when you cancel out the uber-wealthy and uber-poor, the income-gaps are still the widest in urban areas, though strangely they vote the same: Democrat. This is true in SF, LA, NY, Chicago, DC, Boston, Seattle, Portland, Etc. Note: There is no large, thriving middle class in any of these cities. Those large cities can shelter this problem fairly easily, but economically speaking, we live in a multi-polar environment where the big city is no longer the huge engine for jobs or growth...
This policy is to support smart-growth policies of greater density and less suburban sprawl(a leftist utopia) and a future where car-use is greatly minimized. Forget that 90% of employment is not easily accessible by public transportation. The poor move to the suburbs to have a chance at upward mobility and greater opportunities, and this evident by the fact that the greatest employment growth in the past decade came from the suburbs.
_________________
It is not up to you to finish the task, nor are you free to desist from trying.