To avoid toll  payment, drivers may choose to share rides, use transit, travel at less  congested (generally off-peak) times, or travel on less congested routes. HOT lanes have been created by constructing new lanes  or converting existing carpool or High Occupancy Vehicle (HOV) lanes,  some of which had been previously underused, and allowing solo drivers  to use these lanes if they pay a toll. Since the first U.S. congestion pricing project was implemented in Orange  County, California, in 1995, 19 project sponsors have initiated 41 pricing  projects on highways, bridges, and tunnels. The 30 opened projects include 12 HOT lane projects and 18  peak-period priced facilities, covering about 400 miles of priced lanes. Projects range in length from 4.1 miles on the State Route (SR) 133 in  Orange County, California, to nearly 150 miles on the New Jersey  Turnpike, and charge tolls varying from 25 cents to $14. Eleven HOT  lane projects are under construction; in addition, 2 of the 12 HOT lane  projects in operation are extending the length of their tolled lanes. Income equity refers to whether the costs of congestion pricing that  users incur are proportional to their incomes, or whether low-income  drivers are disproportionately affected. DOT Helps Facilitate Congestion Pricing through Project Approvals and Funding for Implementation, Monitoring, and Evaluation

DOT approves all congestion pricing projects on any roadway that  receives federal funds. According to project sponsors that we interviewed, pricing projects  that have not changed a facility’s “footprint,” such as HOV to HOT lane  conversions or peak-period pricing on already tolled highways, bridges, and  tunnels, have received categorical exclusions. Nearly all  congestion pricing projects in operation have received VPPP funds at one  time or another for these purposes. Project Evaluations Have Generally Shown Reduced Congestion, but Other Effects Have Not Been Consistently Assessed

Evaluations of 14 congestion pricing projects in the United States have  generally shown reduced congestion, although other results are mixed, and  not all possible relevant effects have been assessed. In addition, although  the number of cars using HOT lanes has risen, there were fewer people in  the cars—a fact attributed to an increase in the share of toll-paying solo  drivers or a decrease in carpooling on HOT lanes. Peak-period pricing  projects that aim to reduce congestion by encouraging drivers to travel at  off-peak times have shifted some drivers to travel during those times. Other  effects of congestion pricing projects, such as equity income impacts, have  not always been evaluated. Evaluating these impacts is important to  address public and elected officials’ concerns about the effects of pricing  on travelers and communities. Of the project sponsors that have operational congestion pricing, 8 have a  current and completed evaluation of at least one of their projects, for a  total of 14 evaluated projects. Many efforts have been made to assess the effects of congestion pricing  projects on equity, including income equity (the distribution of costs and  benefits of congestion pricing between low- and high-income drivers) and  geographic equity (the relative effects of congestion pricing on two  geographic areas, including the effects of any traffic diversion). Greater Equity and Safety Issues Might Develop as New Projects Are Implemented

		Expanded Use of Pricing Could Raise Equity Concerns

Income and geographic equity concerns may become more prevalent as  congestion pricing becomes more widespread. These concerns may be particularly acute in the future for projects  designed to use pricing not only to manage congestion but also to meet  toll revenue targets. Raising  revenue could be at odds with managing congestion (e.g., increasing  passenger throughput) if higher tolls can produce more revenue from  fewer paying vehicles. Agency Comments

DOT provided technical comments, which we incorporated as  appropriate. We  examined (1) the federal role in supporting congestion pricing, (2) results  of congestion pricing projects in the United States, and (3) emerging  issues in congestion pricing projects. We also discussed the Urban Partnership Agreement (UPA)  and Congestion Reduction Demonstration (CRD) programs—one-time  initiatives that were established with 10 separate federal grant programs. Performance  and monitoring  requirement  Annual reporting  to U.S. DOT  required. DOT. Multi-year  project-specific  and national  evaluations which  U.S. Percent change in route/corridor travel time by time of day  Percent change in the travel time index for comparisons  across sites (having corridors of differing lengths)  Percent change in number of hours of the day with  congested conditions and the number of congested travel  links per day  Percent change in average travel speeds by hour of the  day  Percent change in travel time reliability and planning time  index  Percent change in vehicle and person trips by time of day  and person and vehicle throughput
Change in traveler perceptions about congestion after  deployment of strategies  Level of service in tolled lanes  Travel-time reliability in tolled lanes  Average occupants per vehicle of tolled lanes versus  general purpose lanes
Use of tolling options  Traffic density in tolled lanes  Travel-time reliability (seasonally controlled)
Days exceeding reliability and performance thresholds  End-to-end travel time  Service reliability
User ratings of service performance
Corridor ridership
Corridor mode split (%)

	Federal program Performance measure Equity Analysis

Socio-economic and geographic distribution of benefits  including: tolls paid and adaptation costs; change in travel  time and distance by group; total transportation cost;  environmental impacts  Public perception of the individualized equity impacts of  pricing  Spatial distribution of revenue reinvestment
Reduction in criteria pollutants
Reduction in noise
Reduction in vehicle miles traveled
Qualitative assessment of perceived benefits of the
Reductions in estimated fuel use
Use and impact of alternative fuel vehicles for transit  improvements  Percentage change in crash rate by type and severity  Percentage change in time to clear accidents
Change in the perception of safety by service patrol  operators, state patrol officers, medical first responders,  and bus operators
Change in the perception of safety by travelers  This is a sample of UPA and CRD performance analyses that include measures and metrics related  to the effects of congestion pricing.
Why GAO Did This Study

Many Americans spend frustrating hours each year stuck in traffic. While estimates vary, the Department of Transportation (DOT) estimates that traffic congestion costs the United States $200 billion each year, and that more than one-quarter of total annual travel time in metropolitan areas occurs in congested conditions. Road pricing or congestion pricingassessing tolls that vary with the level of congestion or time of dayaims to motivate drivers to share rides, use transit, travel at less congested times, or pay to use tolled lanes. Since the first U.S. congestion pricing project opened in 1995, 19 project sponsors have 41 pricing projects in operation or under construction. About 400 miles of priced highway lanes including nearly 150 miles on the New Jersey Turnpike are in operation today with current tolls varying from 25 cents to $14.
All U.S. projects in operation are either High Occupancy Toll (HOT) lanes, which charge solo drivers to use newly constructed lanes or carpool lanes, or peak-period pricing projects, which charge a lower toll on already tolled roads, bridges and tunnels during offpeak periods. GAO examined (1) the federal role in supporting congestion pricing, (2) results of U.S. congestion pricing projects, and (3) emerging issues in congestion pricing. Eight project sponsors have current and completed evaluations on at least 1 project, for a total of 14 evaluated projects, all of which GAO reviewed. GAO interviewed officials about the performance of their pricing projects and effects. DOT provided technical comments, which GAO incorporated as appropriate.

What GAO Found

DOT approves all congestion pricing projects on roadways that receive federal funds and provides grants for project studies, implementation, and evaluation. Nearly all HOT lane projects and most peak-period pricing projects in operation today received federal funds at one time or another. DOTs largest programs for congestion relief, the Urban Partnership Agreement and Congestion Reduction Demonstration programs, have provided grant funds totaling nearly $800 million since 2006 to six metropolitan areas to implement pricing and other strategies. DOT requires sponsors of congestion pricing projects to monitor and evaluate performance and, for HOT lanes when applicable, ensure that a federal standard for minimum traffic speeds is met.
The 14 congestion pricing projects that have current and complete evaluations generally show that pricing can help reduce congestion, although other results are mixed, and not all possible relevant impacts have been assessed. HOT lane projects, which aim to reduce congestion by decreasing travel time and increasing speed and the number of vehicles using the lane, have reduced congestion, but some HOT lane projects also added new lanes, and studies did not distinguish the extent to which performance improvements were due to added lanes or pricing. In addition, although the number of cars using HOT lanes has risen, there were fewer people in those cars because of an increase in the proportion of toll-paying solo drivers or a decrease in carpools. Peak-period pricing projects, which aim to reduce congestion by encouraging drivers to travel at off-peak times, have shifted some travel to those times. Other congestion pricing effectssuch as equity income impactshave not always been evaluated. Potential concerns include income equity (whether low-income drivers are disproportionately affected by congestion pricing) and geographic equity (whether one geographic area is more negatively affected than another, such as when traffic diversion occurs). These impacts are important to assess as they address the public and elected officials concerns about the effects of pricing on travelers and communities. Ongoing multi-year evaluations across six metropolitan areas will assess the performance and effects of congestion pricing projects using a specific set of measures to assess the effectiveness of congestion reduction strategies.
Concerns about equity may grow as pricing projects become more widespread. New projects are under construction, and several metropolitan areas have networks of HOT lanes planned that will expand the relatively limited use of pricing today. Equity concerns may become more acute where sponsors are using pricing not only to manage congestion, but also to raise revenue to build new projects. Raising revenue can be at odds with managing congestion (e.g., increasing passenger throughput) if higher tolls can produce more revenue from fewer paying vehicles. Options to address equity issues include using a portion of toll revenues to finance public transit service.