User tolls are said to lessen social inequities related to who pays and who benefits by charging drivers for the actual use of highways, tunnels, or bridges. User charges normally are set to recover the cost of the road project and maintain the predetermined operating condition of that road and are high enough to allow for the private partner's return on investment (Jeffers et al. 2006). Although user fees and congestion pricing schemes are often favored by economists as a way to manage demand, Congressmen Oberstar and DeFazio (2007) asserted that tolls are regressive because they charge drivers of all income levels the same amount and suggest that electronic toll collection technology can reduce or eliminate tolls paid by low income drivers. The RPA (2007) suggests considering the effect to middle- and low-income groups when developing the toll-increase schedules, such that these groups are not disproportionately affected.
PPP legislation and/or concession agreements may include provisions setting toll rates lower than required to support financing; however, in exchange, the public sector would provide funding or subsidies to attract private sector participation. In Chile, the public sector establishes the maximum toll rate, and the evaluation of PPP proposals takes into account the proposed toll rates, among other factors (Izquierdo and Vasallo 2004). Similarly, some PPPs in Australia have been awarded to bidders that propose operating the facilities with the lowest toll (GAO 2000b). Sixteen of the states with PPP-enabling legislation already allow the combination of public sector funding with private funding on a PPP project (FHWA PPP enabling legislation survey 2007).