1. Other advanced economies with significant PPP programs are Australia, the Czech Republic, and Hungary (see Hemming 2004). Among emerging economies, PPPs have been used by China and India, and by several countries in Latin America.
2. From the 1790s to 1821, more than 2,000 companies, looking for ways to make profits by providing road links between interior agricultural markets and ports, financed, built, and operated toll roads with a combined extension of more than 10,000 miles.
3. Pennsylvania shifted its highway bridge funds on maintenance from 75 percent in 2007 to 96 percent currently.
4. However, as stipulated by the concession agreement, the city of Chi-cago gave existing employees the opportunity to move to other public jobs, an offer taken by 100 of 105 unionized workers (Transportation Research Board of the National Academies 2009). This suggests that, at least in the short run, efficiency gains at the Chicago Skyway were the flip side of efficiency losses elsewhere in the city.
5. Note, however, that for the Indiana Toll Road there is a commitment by the leaseholder of $770 million in improvements, so it has some aspects of a brownfield partnership.
6. In the United States and in the United Kingdom, it is not uncommon to have the design of projects negotiated directly with the private party. This requires much confidence in the incorruptibility of the public officials involved in these negotiations
7. These data are from Her Majesty's Treasury, 2009.
8. See Hellowell and Pollock (2007) for a criticism of the methodology, however.
9. Road wear and tear is proportional-as a rule of thumb-to the fourth power of axle loading. See http://pavementinteractive.org/index. php?title=ESAL. The implication is that, in most countries, the tolls paid by trucks are much lower than the wear and tear costs they cause.
10. See "Greenville SC Southern Connector toller files for bankruptcy," June 25, 2010, http://www.tollroadsnews.com/node/4808.
11. The exceptions are the Port of Miami Tunnel, the I-595 corridor in Florida, the Eagle Commuter Rail Project in Denver, and Route 3 in Boston.
12. Personal communications with Richard B. Norment and John D. Lynch. Note, however, that the following states do not charge tolls (except, in some cases, for bridges crossing to another state): Arizona, Connecticut, Hawaii, Idaho, Mississippi, Montana, New Mexico, North Carolina, South Dakota, Tennessee, and Wyoming.
13. In Engel et al. (2007) we derive a flexible-term contract where firms bid both a cap on the present value of user fee revenue they desire and a minimum income guarantee. The regulator com-bines both bids using a scoring function. We show that these "two-threshold" contracts have many (but not all) of the advantages of PVR contracts in the case of intermediate- and low-demand projects.
14. Traditionally, firms bid on the lowest toll, the shortest contract term, or the lowest payment to the government. In all these cases, the contract length is set before demand for the project can be known.
15. Colombia ran a flexible-term auction a couple of years before where firms bid on total income, without discounting.