How is suburban infrastructure heavily subsidized?
No actually. A heavily subsidized project like the Big Dig cost vastly more per mile than a suburban side street.
Furthermore, you can't just assume that cities could exist in isolation. The inhabitants wouldn't last long without numerous inputs (food, water, power, etc.) that they can't provide for themselves and that require areas with less density to produce for them.
It's very hard to come up with numbers because everything is effectively a large interconnected system. Some patterns are probably more efficient than others but you can't just assume everyone into urban living.
Residential sprawl in the suburbs is not producing food, etc. Nobody is advocating turning all cropland into city, that wouldn’t make any sense.
The advocacy is for changing tax/zoning/planning policy to encourage residential density and mixed residential-commercial use neighborhoods. Even in towns of, say, 30k people, having a denser town center full of low-rise apartment buildings and walkable neighborhoods is a big advantage for economic efficiency, for human health, and for the environment.
Having people commute one-person-per-car for 1–2 hours per day, drive cars to school, to shops, to restaurants, to the post office and the library, ... is ridiculously destructive at a societal scale. All the public infrastructure and public services cost several times as much per capita as life at higher density, not even to mention the economic/environmental cost of the cars themselves, or the massive time opportunity cost of the commuting.
> you can't just assume everyone into urban living.
Nope. But people who want to live somewhere very economically wasteful should be prepared to pay for it.
Of course you are completely right that we need rural areas where we for example grow good or do other things that need lots of space. However, that doesn't happen in most suburbs. In fact suburbs typically keep their density artificially low for non other than vague aesthetic reasons. I myself live in the suburbs and find it very convenient. Would I do so if I had to pay for the street and sewer that lead to my house like my parents who live in Germany had to? Probably not. My parents had to pay about 20k, and that was because most of their property was on a main, federal road. Otherwise it would have been closer to 40. At the time I thought that was insane, but given that in a multi story apartment building the cost would have been much lower, it seems fair in hindsight.
Personally, I'm no particular fan of traditional suburbs. But I'm also unconvinced that it's even desirable to especially encourage urban living--especially if, in practice, that means encouraging living in a few specific walkable cities. Presumably urban living in this context doesn't mean Las Vegas.
* Streets are paid for in the United States through the gas taxes collected from the distribution of fuels. It is a user tax.
* Water and electricity are maintained and run by utilities through their use rates. I will pre-empt the discourse and note that water is heavily subsidized by the government and creates weird incentives (I am looking at you Arizona with your green lawns).
* Transit, bicycle, and pedestrian movements are subsidized by the gas tax. In this case, your statement would be true.
This is not the whole story.
http://taxfoundation.org/article/gasoline-taxes-and-user-fee... (ignore the advocacy here, just look at the numbers)
1. Toll revenue goes to toll facilities. Private public partnerships (PPP's) need to be repaid and the tolls collected go directly to the repayment of the bonds, maintenance, and general operations.
2. Transit siphons monies away from the use tax. Transit exists only because of the user tax. While people see autos as bad, they fund the transit that provides movement for poor individuals. I am okay with this.
3. State and local roads is oddly worded in this phrase and brings a warning to my periphery review. Most states have amendments and/charters that require fuel funds to be allocated to the roadways, Wisconsin (http://www.wsdot.wa.gov/Finance/fueltaxes.htm), Florida, and a number of others that do not take money from other sources. In fact in Florida, the highway funds are raided yearly to fill in budget gaps.
The best I can come up with on how this chart was made to get the 50% concept is that FHWA provides matching funds for projects, the reason is that they want to provide a carrot to meet federally required mandates, such as interstates and state roads on the National Highway System. If you kick in these monies, which is free money, then you can get there. However, this is an advocacy program.
One last note. The writing is on the wall for the gas tax long term. The federal level is already having a shortfall in revenue because of the CAFE standards increase. This is why states like Oregon are trying out the Vehicle Miles Traveled tax, because they need to switch out how the roadways are paid for.