United States Government Accountability Office

GAO Report to the Ranking Member, 

Committee on Environment and Public 

Works, U.S. Senate 

SURFACE 

TRANSPORTATION 

Strategies Are 

Available for Making 

Existing Road 

Infrastructure 

Perform Better 

July 2007 

 

GAO-07-920 
What GAO Found

United States Government Accountability Office

Why GAO Did This Study

Highlights

Accountability Integrity Reliability

July 2007

SURFACE TRANSPORTATION 

Strategies Are Available for Making 

Existing Road Infrastructure Perform 

Better 

Highlights of GAO-07-920, a report to the 

Ranking Member, Committee on 

Environment and Public Works, U.S. 

Senate 

For the past several decades, the 

capacity of the nation’s road

network has not grown fast enough 

to keep pace with demand. The 

increasing congestion is apparent

to millions of commuters and 

freight operators. Although road

building is perhaps the most 

familiar antidote, Congress, the 

Department of Transportation 

(DOT), and transportation research

have emphasized the need to more

efficiently use the existing

infrastructure as a means to

control congestion. 

GAO was asked to examine various 

issues associated with increasing 

the efficient use of existing

infrastructure. This report 

examines the following questions:

(1) What factors inhibit the 

efficient use of the existing

infrastructure of roads and 

highways? (2) What techniques 

have been developed for making

the current infrastructure more

efficient and what is known about 

the results? (3) How have local 

decision makers implemented 

these techniques? (4) What 

strategies exist for increasing the 

use of such techniques? To

address these questions, GAO 

reviewed existing studies,

examined efforts in five states, and 

sought transportation officials’ 

views, among other things. 

GAO is not making

recommendations in this report. In 

commenting on a draft of this

report, DOT provided technical

clarifications, which we

incorporated as appropriate. 

Three broad factors inhibit efficient use of existing roads. First, many were 

not designed and built to meet today’s traffic volumes, and their operation 

has not changed sufficiently to better meet current volumes. Second, the 

federal and state revenue-raising structure does not provide incentives for 

drivers to use roads efficiently because it does not capture all the costs

involved in using roads at time of peak demand. Third, information about 

which investments produce the highest estimated social benefits is limited 

when decisions are made about how to address congestion. 

Two types of techniques have been developed for making current roads 

more efficient. One enhances capacity through better operations and use of 

technology, such as timing traffic signals to improve traffic flow. The other 

influences behavior about when and where to drive, through such specific 

means as flexible work schedules, and charging drivers tolls to use roads 

during peak hours. Research suggests that these techniques are most 

effective when tailored to the particular situation and used in combination. 

In the states GAO reviewed, officials chose varying techniques but tended to 

implement them with a similar three-pronged approach: (1) changing 

planning and related processes to give these techniques more priority, (2) 

developing creative mechanisms to fund them, and (3) collaborating with 

multiple stakeholders to put them in place. Officials said many of the 

techniques, while helpful, provided only marginal benefits, because several 

persistent challenges prevented greater use. These challenges ranged from 

resolving jurisdictional authority to finding alternative funding sources. 

Although many strategies exist for making greater use of these techniques, 

they vary depending on the level of government involved. Three strategies

cut across all levels of government: (1) considering how the private sector 

can be used in managing existing road infrastructure, (2) expanding the userpay concept for managing demand and generating revenue for transportation 

investments, and (3) measuring results and managing with them in mind. 

Several other strategies, such as applying techniques on a regional basis and 

integrating transportation planning more fully with land-use planning, relate 

primarily to state and local governments. Strategies at the federal level, 

where participation in transportation projects relates primarily to financial 

assistance and policies affecting system performance and safety, includes 

linking federal funding to performance, increasing flexibility for states and 

localities, and placing additional focus on projects with national benefits. 

Examples of Various Congestion Mitigation Techniques 

LANE

HOT

LANE

HOT

Source: GAO.

High-occupancy toll

(HOT) lanes Incident management program Telework policies Traffic signal timing

www.gao.gov/cgi-bin/getrpt?GAO-07-920.

To view the full product, including the scope 

and methodology, click on the link above. 

For more information, contact JayEtta Z. 

Hecker at (202) 512-2834 or 

heckerj@gao.gov. 
Contents 

Letter 1

Results in Brief 3

Background 5

Three Broad Factors Inhibit Efficient Use of Roads 13 

Various Techniques Have Been Developed to Make the Current 

Infrastructure More Efficient 18 

Transportation Decision Makers Are Using Similar Approaches for 

Implementing Congestion Mitigation Techniques, but Challenges 

Exist 24

Various Strategies Exist for Increasing the Efficient Use of 

Infrastructure 32

Concluding Observations 43 

Agency Comments and Our Evaluation 44 

Appendix I Objectives, Scope, and Methodology 46 

Appendix II Congestion Mitigation Techniques and Benefits 48 

Appendix III GAO Contact and Staff Acknowledgments 51

Tables 

Table 1: Examples of Long-range and Short-range Transportation 

Plans at Locations GAO Visited 25 

Table 2: Selected Congestion Mitigation Techniques That Enhance 

Capacity 48

Table 3: Select Congestion Mitigation Techniques That Influence 

Driver Behavior 49 

Figures 

Figure 1: Percentage Change of Vehicle Miles Traveled and New 

Construction of Lane Miles between 1980 and 2005 7 

Figure 2: Representation of Levels of Service on a Two-Lane 

Highway 10

Figure 3: Percentage of Highway Capacity That Is Reduced When 

Vehicle Incidents Occur 15 

Page i GAO-07-920 Surface Transportation
Figure 4: Select Congestion Management Techniques that Enhance 

Capacity and Influence Driver Behavior and Demand 21 

Figure 5: Express Lanes and General Purpose Lanes on State Route 

91 in Orange County, California 23 

Figure 6: Florida Road Ranger Incident Response Vehicle 29 

Figure 7: Strategies for Making More Efficient Use of Existing 

Infrastructure 33

Figure 8: Representation of the VII Mobility Applications 35 

Figure 9: Minnesota’s “MnPass” Program 41 

Abbreviations 

DOT Department of Transportation 

FHWA Federal Highway Administration 

FTA Federal Transit Administration 

HOT high-occupancy toll lane

HOV high-occupancy vehicle 

ICM Integrated Corridor Management 

ITS intelligent transportation system 

NCHRP National Cooperative Highway Research Program 

NTOC National Transportation Operations Coalition 

SAFETEA-LU Safe, Accountable, Flexible, Efficient Transportation Equity 

Act: A Legacy for Users 

TIP Transportation Improvement Program 

VII Vehicle Integration Initiative 

VMT vehicle miles traveled 

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Page ii GAO-07-920 Surface Transportation
United States Government Accountability Office

Washington, DC 20548 

July 26, 2007

The Honorable James M. Inhofe 

Ranking Member 

Committee on Environment and Public Works 

United States Senate 

Dear Senator Inhofe: 

Mobility—that is, the movement of passengers and goods through the 

transportation system—is critical to the nation’s economic vitality and its 

citizens’ quality of life. Mobility gives people access to goods, services, 

recreation, and jobs; gives businesses access to materials, markets, and 

people; and promotes the movement of personnel and material to meet 

national defense needs. While the transportation system that provides this 

mobility is made up of air, marine, and various modes of surface 

transportation, the nation’s road network is the transportation system that 

most citizens use daily. It is also the critical pathway for the movement of 

freight. 

Mobility—that is, the movement of passengers and goods through the 

transportation system—is critical to the nation’s economic vitality and its 

citizens’ quality of life. Mobility gives people access to goods, services, 

recreation, and jobs; gives businesses access to materials, markets, and 

people; and promotes the movement of personnel and material to meet 

national defense needs. While the transportation system that provides this 

mobility is made up of air, marine, and various modes of surface 

transportation, the nation’s road network is the transportation system that 

most citizens use daily. It is also the critical pathway for the movement of 

freight. 

For the past several decades, the capacity of the national road network 

has not grown fast enough to keep pace with the growing demand. 

Population, income levels, and economic activity have risen considerably 

and with them have come significant increases in travel demand and 

freight movement on the surface transportation system. The result is 

apparent to millions of commuters and freight operators: increasing 

number of hours spent inching along clogged roads and highways, 

especially at rush hours and other times of peak demands. The economic

implications are significant, ranging from wasted fuel and time as cars idle

in traffic to increased logistics costs for business as the unreliability of the 

systems grows. While building additional roads is perhaps the most 

familiar way for addressing congestion, Congress, the Department of 

Transportation (DOT), and transportation research have emphasized the 

need to more efficiently use the existing infrastructure as a means to help 

control congestion. This could be done both by managing the existing 

network to enable it to handle more traffic and by managing the demands 

placed upon it. However, transportation stakeholders and experts have 

generally acknowledged that we are not using the existing infrastructure 

as efficiently as possible. For example, in its National Strategy to Reduce 

Congestion on America’s Transportation Network, DOT notes that “at its 

most fundamental level, highway congestion is caused by the failure to 

For the past several decades, the capacity of the national road network 

has not grown fast enough to keep pace with the growing demand. 

Population, income levels, and economic activity have risen considerably 

and with them have come significant increases in travel demand and 

freight movement on the surface transportation system. The result is 

apparent to millions of commuters and freight operators: increasing 

number of hours spent inching along clogged roads and highways, 

especially at rush hours and other times of peak demands. The economic

implications are significant, ranging from wasted fuel and time as cars idle

in traffic to increased logistics costs for business as the unreliability of the 

systems grows. While building additional roads is perhaps the most 

familiar way for addressing congestion, Congress, the Department of 

Transportation (DOT), and transportation research have emphasized the 

need to more efficiently use the existing infrastructure as a means to help 

control congestion. This could be done both by managing the existing 

network to enable it to handle more traffic and by managing the demands 

placed upon it. However, transportation stakeholders and experts have 

generally acknowledged that we are not using the existing infrastructure 

as efficiently as possible. For example, in its National Strategy to Reduce 

Congestion on America’s Transportation Network, DOT notes that “at its 

most fundamental level, highway congestion is caused by the failure to 

Page 1 GAO-07-920 Surface Transportati ansportation
develop mechanisms to efficiently manage use of existing capacity and 

expand capacity at locations were the benefits are the greatest. Although 

more efficiently using existing infrastructure is intended to help manage 

congestion, the goal of such efforts is not to completely eliminate or 

prevent congestion. 

Given the importance of the nation’s road network, the federal 

government has partnered with states in developing and maintaining it. In

recent years, the Federal Highway Administration (FHWA) has provided 

nearly $34 billion each year to states to build and improve roads and 

bridges and meet other transportation needs. Since transportation 

research and our work has indicated that the current system will not be 

able to meet future demand, you asked us to provide information on 

several key questions related to what is being done—and what else might

be needed—in adjusting to this changing environment and ensuring our 

nation’s mobility. More specifically, this report addresses the following 

questions: 

1. What factors inhibit the efficient use of the existing infrastructure of 

roads and highways? 

2. What techniques have been developed for making the current

infrastructure more efficient and what is known about the results of 

these techniques? 

3. How have local decision makers implemented these techniques? 

4. What strategies exist for increasing the efficient use of existing 

infrastructure? 

To address these questions, we conducted a review of relevant literature,

reports, studies, and our prior research and interviewed federal, state, and 

local transportation officials, as well as representatives from various 

industry associations with experience in developing, implementing, or 

analyzing these techniques. We also conducted site visits or interviews 

with state and local transportation officials in California, Colorado, 

Florida, Virginia,1

 and Washington. We selected this nongeneralizable 

sample of states based on the level of congestion of selected metropolitan 

areas within these states, including Denver; Northern Virginia; Orlando; 

San Diego; San Francisco/San Jose/Oakland; and Seattle; and additionally 

 1

These interviews were conducted by telephone. 

Page 2 GAO-07-920 Surface Transportation
on the states’ experience with using congestion mitigation techniques to 

achieve geographical diversity. We also visited Aurora and Boulder, Colo.; 

Altamonte Springs, Fla.; Hampton Roads, Va.; and Bellevue and Issaquah, 

Wash., to gain some insight into the implementation of congestion 

management techniques in smaller jurisdictions. During these site visits, 

we interviewed federal, state, and local transportation officials and toured 

operations centers. In addition, we reviewed studies and documentation 

on how these and other metropolitan areas and states have implemented 

congestion management techniques and their results. We conducted our 

work from September 2006 through July 2007 in accordance with generally 

accepted government auditing standards. (See app. 1 for more information 

about our objectives, scope and methodology.) 

Three broad factors inhibit efficient use of roads and highways: design and 

operation factors; the revenue-raising structure; and a limited focus on 

selecting projects that produce the highest net social benefits in the 

current decision-making process. First, many roads were not designed and 

built to meet current traffic volumes, and operational changes—such as 

the timing of traffic signals—have not changed sufficiently to cope with 

the increased use. Second, the federal and state transportation revenueraising structure, which collects the majority of revenues through motor 

fuel taxes and other user fees, does not provide incentives for drivers to 

take into account the external costs, such as increased travel time for 

other drivers, they impose in deciding when, where, and how to drive. For

example, the tax rate on gasoline is the same regardless of whether drivers 

drive in congested or uncongested periods. Third, there is a limited focus 

in the current decision-making process on selecting projects that will 

produce the highest net social benefits. Decision makers also are limited in

their ability to identify and put in place infrastructure investments that 

would produce the highest estimated social benefits because the current

decision-making process is compartmentalized by mode and is not driven 

by economic analysis. 

Results in Brief 

Two categories of congestion mitigation techniques have been developed 

to improve the efficiency and better optimize the performance of the 

existing infrastructure. The first category includes techniques that 

enhance road capacity through better operations, such as incident 

response vehicles that quickly restore traffic flow after vehicle crashes, or 

the deployment of transportation technology, such as optimizing the 

timing of traffic signals to improve traffic flow. The second category 

includes techniques designed to better acknowledge the impact of using 

the road system during times of peak demand; these techniques influence

Page 3 GAO-07-920 Surface Transportation
drivers to make alternative choices, such as car pooling or shifting trips to 

less congested times. Studies and evaluations of projects indicate that

these congestion mitigation techniques have the potential to provide 

benefits such as reduced congestion delays and improved traffic flows that 

maximize existing capacity. These studies and evaluations also indicate

such techniques are most effective when tailored to the particular 

situation and used in combination. 

At locations we reviewed, officials chose varying congestion mitigation 

techniques but tended to implement them with a similar three-pronged 

approach: (1) changing planning and related processes to give them higher

priority, (2) developing creative mechanisms to fund them, and (3) 

collaborating with multiple stakeholders to put them in place. For 

example, in considering which projects to select for funding, the 

metropolitan planning organization for the Denver region now awards 

points to projects that use certain congestion mitigation techniques, such

as installing left-turn lanes, coordinating traffic lights, or managing 

incidents. Officials for the Denver region said they hope awarding points 

will provide incentives for local planners to include such techniques in 

their projects. Transportation officials said the mode-specific, “stovepiped” funding structure for transportation projects, together with a 

general lack of resources for transportation projects, constrained their 

ability to use these techniques. As a result, they said, they often have had 

to find alternative methods to supplement traditional funding sources. 

Officials also reported working with multiple partners to implement 

congestion mitigation techniques. They said the success of these 

techniques depends on coordination among many partners. While officials 

said the techniques produced benefits, these officials also called attention

to various challenges that tended to preclude wider use. These challenges

ranged from resolving jurisdictional authority to identifying sufficient 

funding to allow implementation on a broader scale. As a result, they said, 

the approach they used to implement these techniques could provide only 

marginal improvement to the efficiency of the road network. 

Various strategies exist for increasing the efficient use of infrastructure. 

We grouped the strategies by the level of government best suited to 

consider and implement them, given their current authorities, roles, and 

responsibilities. In some cases, all levels of government would need to be 

involved in implementing the strategy; in other cases, the federal 

government or a state government would be most appropriate to 

implement the strategy. We identified three strategies that cut across all 

levels of government, including (1) considering how the private sector can

be used in managing existing road infrastructure, (2) expanding use of the 

Page 4 GAO-07-920 Surface Transportation
user-pay concept for managing demand and generating revenue for 

transportation investments, and (3) developing a systematic performancebased management approach to increase the accountability of public 

expenditures and to link performance to investment decisions. We also 

identified strategies that would be most appropriate for state and local

governments to consider, including applying congestion mitigation 

techniques on a regional basis and fully integrating transportation and 

land-use planning. For example, traffic signal timing is one technique that 

can provide significant benefits to drivers by providing for the smooth 

flow of traffic along streets and highways. To fully enhance mobility, 

jurisdictions need to coordinate the timing along an entire corridor, which 

often crosses multiple jurisdictions. Finally, we identified strategies that

the federal government could consider to help increase the efficient use of

infrastructure. These strategies include (1) linking funding more directly 

to performance, (2) increasing the flexibility provided to state and local 

governments to promote innovative solutions, and (3) focusing on projects 

(or transportation corridors) of national interest. For example, the federal 

government could also use incentives to link funding to particular 

outcomes, such as encouraging state and local governments to increase 

the efficient use and performance of existing infrastructure. According to

transportation research and transportation officials and experts we 

interviewed, the strategies are not mutually exclusive and ideally would be 

implemented in a comprehensive manner. 

DOT, including FHWA, reviewed a draft of this report. DOT officials 

provided technical clarifications, which we incorporated as appropriate. 

Background 

Pressure on Road System 

Continues to Build 

Road usage, as measured by vehicle miles traveled (VMT), has grown over 

the last 25 years. From 1980 through 2005, the most recent years for which 

data are available, road usage grew at an average annual rate of 2.7 

percent from 1980 through 2005. A number of demographic and economic 

trends contribute to this increase in road usage, including the shift from 

urban to suburban areas by businesses and households, rising household 

incomes, and a greater reliance on trucks to move freight. For example, 

research shows that car ownership and VMT rise with income. The 

average U.S. household income (in 2005 dollars) grew from $47,263 in 1980 

to $63,344 in 2005, according to U.S. Census Bureau data, fueling the 

number of cars on the road and the number of miles traveled.

Page 5 GAO-07-920 Surface Transportation
Increasing road usage has led to growing congestion in the nation’s 

transportation system. In 2006, FHWA reported that congestion on U.S. 

highways between 1982 and 2003 had increased in extent, duration, and 

intensity. For example, in the largest U.S. cities, 67 percent of travel was 

impacted by congestion—up from 33 percent in 1982. As a result, drivers 

in urban areas are increasingly experiencing what FHWA calls recurring 

congestion, which is congestion that occurs day-in and day-out, such as 

slowdowns that occur during morning and afternoon commutes, even

when road and weather conditions are ideal. This type of congestion 

occurs simply because so many cars and trucks are trying to use the road

at the same time; the network as currently designed and operated simply 

cannot handle the volume. The imbalance between demand and supply 

also affects the network’s ability to recover from what FHWA refers to as 

nonrecurring congestion, which is caused by crashes, weather, 

construction, or other event-driven variability. The increased volume of 

traffic often exacerbates the effects of such slowdowns and roadblocks in 

traffic flow. Both categories of congestion can lead to significant loss of 

productivity with real economic impacts. For example, the Texas 

Transportation Institute estimates that U.S. drivers experienced 3.7 billion 

hours of travel delay and wasted 2.3 billion gallons of fuel in 2003 due to 

congestion in the top 83 urban areas. The Texas Transportation Institute 

projected the total cost at $63 billion (in 2003 dollars). In addition to the 

economic effects, congestion can also lead to negative environmental 

impacts. For example, studies have shown potential negative health 

effects from living near busy roads, with one recent study showing that 

children in neighborhoods with higher levels of traffic pollutants have 

shown an increased prevalence of asthma and bronchitis symptoms.2

Capacity Has Not Kept 

Pace with Demand, and Is 

Not Likely to Do So 

Several strategies exist for addressing the growing congestion on roads, 

including constructing new infrastructure to add capacity, improving 

maintenance on existing capacity, and managing existing capacity through 

operational methods. While building new capacity is still a viable strategy 

in certain situations, such as in areas where there is available space to 

accommodate new roads or to add more lanes to existing roads, overall,

the construction of new capacity is not keeping pace with the growing 

demand. For example, while VMT has almost doubled from 1980 to 2005, 

 2

Janice J. Kim, et al., “Traffic-related Air Pollution near Busy Roads: The East Bay 

Children’s Respiratory Health Study,” American Journal of Respiratory and Critical Care

Medicine 170 (2004); 520-526.

Page 6 GAO-07-920 Surface Transportation
growing at an average annual rate of 2.7 percent, during the same time, 

new construction of lane miles increased capacity at an average annual

rate of 0.2 percent, so that by 2005 total capacity was only 6 percent 

greater than in 1980. (See fig. 1.) 

Figure 1: Percentage Change of Vehicle Miles Traveled and New Construction of Lane Miles between 1980 and 2005 

0.0

0.4

0.8

1.2

1.6

2.0

2.4

1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Percentage

Source: GAO analysis of highway statistics from FHWA.

Year

VMT

Lane miles

Note: Index = 1 for 1980. 

Many factors appear to have contributed to the slow increase in supply 

relative to demand, with the several listed below often cited as most 

critical. 

• The purchasing power of available funding for highway construction 

and maintenance is declining. Although transportation revenues have 

continued to increase in nominal terms, with total highway revenues for 

states growing an average of 3.6 percent per year between 1995 and 2004, 

the federal and state motor fuel tax rates—the mainstay of state highway

revenue—have not kept up with inflation. According to DOT and FHWA 

data, this has resulted in a decline in the purchasing power in real terms of 

revenues generated by federal and state motor fuel tax rates since 1990.

• An increasing proportion of available funds is being spent to preserve 

existing infrastructure. State and regional transportation decision makers 

are devoting more funding to highway investments that preserve, enhance, 

Page 7 GAO-07-920 Surface Transportation
and maintain existing infrastructure than to investments that add capacity. 

Existing infrastructure is aging and keeping it functional is becoming more 

expensive. According to FHWA data, of the $70.3 billion spent nationally in

2004 on highway capital spending, 52 percent ($36.4 billion) was spent on 

system preservation, compared with 39 percent ($27.5 billion) for new 

construction.3

 In 1993, 45 percent of the total was spent on system 

preservation.

• The recent growth of road construction costs exceeds the overall rate of 

inflation. The cost of building new capacity and maintaining existing 

capacity has increased steadily over the last few years, at a rate that 

exceeds inflation. The composite bid price index4

 for highway 

construction has almost doubled since 1987, according to FHWA. In 

particular, the price of construction materials has increased significantly

in the last few years because of rising diesel and asphalt prices. 

• Road-building solutions are becoming less popular. In many locations, 

the public has grown increasingly resistant to carving out additional space

for roads, both for environmental and for social reasons. As a result, state 

and local governments have increasingly identified quality of life and 

environmental sustainability as key principles in their long-term regional 

plans for managing growth and investing in transportation infrastructure. 

Transportation planners will have to make trade-offs between facilitating 

increased mobility—through adding new road capacity—and giving due 

regard to environmental and other social goals. 

Building new infrastructure to keep pace with demand may continue to be

problematic in the future, because revenues from the Highway Trust 

Fund—the major source of federal highway and transit funding—are 

projected to continue to erode in real terms due to inflation. Additionally, 

funding authorized in the most recent highway and transit program 

legislation is expected to outstrip the growth in trust fund receipts. 

According to recent estimates from the Congressional Budget Office and 

the President’s budget, the trust fund balance will steadily decline and 

 3

The remaining 9 percent was spent for system enhancements such as safety, operational, 

or environmental enhancements. 

4

The composite bid price index is composed of six indicator items: common excavation, to 

indicate the price trend for all roadway excavation; Portland cement concrete pavement

and bituminous concrete pavement, to indicate the price trend for all surfacing types; and 

reinforcing steel, structural steel, and structural concrete, to indicate the price trend for 

structures. The index is adjusted to account for inflation, so a doubling represents a 

substantial loss in purchasing power. 

Page 8 GAO-07-920 Surface Transportation
reach a negative balance of more than $14 billion by the end of fiscal year 

2012.

5

 The overall fiscal imbalance the nation faces makes it difficult to 

find an easy fix for this problem by seeking to significantly expand federal

contributions. As a result, in 2007, we placed financing of the nation’s 

transportation infrastructure on our list of high-risk issues facing federal 

decision makers.6

Given these trends, state and local governments are turning to the other 

tools to manage congestion, including improving the efficiency of the 

existing road network. When considering how to better manage existing 

road infrastructure, two key concepts are important and will be referred to

often in this report: maximizing the flow of vehicles and promoting 

efficient use of the road through users’ choices. 

With Capacity 

Constrained, Other 

Approaches Are Receiving 

More Attention 

• Maximizing the flow of vehicles. This concept deals with achieving 

maximum flow of vehicles through a stretch of highway. Once a road 

reaches a certain capacity level, drivers’ ability to travel at or near the 

posted speed limit begins to decrease, because traffic flow is increasingly 

affected by such things as an inability to change lanes to pass slower 

vehicles or a need to slow down to allow merging vehicles to enter. 

Transportation research uses “level of service”7

 to measure the speed and 

travel time, freedom to maneuver, traffic interruptions, and comfort and 

convenience for a road. As figure 2 shows, level of service ranges from 

“free flow,” where the amount of traffic is small enough to allow travel at

the posted speed limit, to “stop and go flow,” where a road has become so 

packed with vehicles that drivers’ speeds can fall to far lower than the 

speed limit. When the number of vehicles approaches maximum capacity,

speeds are slowed to the point that a road can accommodate fewer total 

vehicles in a given period of time. As the figure shows, a road is 

considered to have a “stable flow” when the number of vehicles represents 

between roughly 50 to 85 percent of the road’s maximum carrying 

capacity. 

 5

GAO, Performance and Accountability: Transportation Challenges Facing Congress and

the Department of Transportation, GAO-07-545T (Washington, D.C.: Mar. 6, 2007); and

GAO, Highway Trust Fund: Overview of Highway Trust Fund Estimates, GAO-06-572T 

(Washington, D.C.: Apr. 4, 2006). 

6

GAO, High Risk Series: An Update, GAO-07-310 (Washington, D.C.: January 2007). 

7

Definitions of level of service are dependent on the specific road type, such as multilane 

highways or urban streets. There are other measures that are used such as travel time 

reliability.

Page 9 GAO-07-920 Surface Transportation
Figure 2: Representation of Levels of Service on a Two-Lane Highway 

Level of service A

(0-29% of capacity)

Level of service B

(29%-47% of capacity)

Level of service C

(47%-68% of capacity)

Level of service D

(68%-85% of capacity)

Level of service E

(85%-100% of capacity)

Level of service F

(over 100% of capacity)

Source: GAO analysis of the Transportation Research Board of the National Academies Highway Capacity Manual.

Free flow. Drivers unaffected by 

others in traffic stream, free to 

select speed and maneuver.

Still free flow but with more notice 

of other drivers. Slight loss in 

freedom to maneuver.

Stable flow but the beginning of the 

flow in which operations become 

significantly affected by the 

presence of other drivers. Declining 

comfort and convenience.

High density but stable flow. 

Maneuvering restricted.

At or near capacity. Speeds

reduced to slow but uniform flow. 

Maneuvering extremely difficult. 

Flow unstable.

Stop-and-go flow. Queues develop 

behind breakdowns in flow.

0

MPH

Speed

limit

0

MPH

Speed

limit

0

MPH

Speed

limit

0

MPH

Speed

limit

0

MPH

Speed

limit

0

MPH

Speed

limit

Page 10 GAO-07-920 Surface Transportation
• Promoting efficient use through users’ choices. This concept deals with 

ensuring that road users make choices about when to drive based on the 

full costs of using the road. Economists see congestion as a byproduct of 

drivers’ decisions to use a specific road based only on the benefits they 

receive and the costs that they incur (for example, the gasoline they use 

and the time they spend) and not on the external costs they impose on 

others, such as increased travel time for others and increased pollution.8

From an economic perspective, a road is not efficiently “priced” when this 

condition occurs. To achieve more efficient use, some type of pricing 

mechanism, such as a toll or surcharge, would need to be implemented to 

take into account the cost that a driver imposes on others when using a 

congested road. Efficient road pricing is basically seen as a way to ration 

limited resources—for example, the use of a highway during times of peak 

demand, such as rush hour. A toll or surcharge, under such conditions, 

would create incentives for drivers to shift their travel to periods of lower 

demand, use other roads, or make other adjustments, when the costs of 

their decision to drive during congested periods exceed the benefits they 

receive. 

Although more efficiently using existing infrastructure is intended to help

manage congestion, the goal of such efforts is not to completely eliminate 

or prevent congestion. For example, an exorbitantly priced toll on a road 

that discourages drivers from using it would create an inefficient use of 

the infrastructure—even though there would be no congestion on the 

road. Similarly, a road network that could disperse a crowd of 90,000 from

a football game and create no congestion would require many lanes that 

would likely be underused at all other times of the year. Economic 

efficiency is thus a balancing act. 

Congress has recognized the importance of improving the efficient use of 

the existing road infrastructure through the passage of Safe, Accountable, 

Flexible, Efficient Transportation Equity Act: A Legacy for Users 

(SAFETEA-LU). SAFETEA-LU addresses both current and future 

challenges facing our nation’s transportation system by promoting 

efficient and effective federal surface transportation programs. In 

particular, SAFETEA-LU establishes new requirements and programs to 

 8

More specifically, economists consider a road efficiently used when, at the margin, an

additional driver using the road perceives his or her personal benefits to exactly offset both 

his or her personal costs, as well as other social costs, which include such costs as the

additional travel time he or she imposes on other drivers, the wear and tear on the road 

surface, and the pollution to the society. Economists call this point as an equilibrium at 

which the marginal benefits to the additional user equal the marginal social costs. 

Page 11 GAO-07-920 Surface Transportation
promote the efficient use of existing infrastructure. For example, 

SAFETEA-LU requires that DOT establish a real-time system management 

information program to build the capability to monitor, in real time, the 

traffic and travel conditions of major highways and to share this 

information with state and local governments to assist in relieving 

congestion and providing traveler information. According to FHWA 

officials, a notice of proposed rule making for this program is expected to

be published in late 2007. 

Multiple stakeholders are involved in the construction, maintenance, and 

operation of the nation’s road infrastructure. These stakeholders include 

the federal government, state and local governments, and the private 

sector. 

Federal Government Is 

One of Many Stakeholders 

in Operating and Managing 

the Road Infrastructure 

• The federal government, primarily through FHWA and the Federal Transit 

Administration (FTA), provides funding to state and local governments for 

road and transit infrastructure, establishes legislation and regulations that 

influence the performance and safety of the system, and administers 

transportation programs that cover a range of areas. 

• On the front lines of transportation decision making, state and local 

governments, through departments of transportation and metropolitan 

planning organizations, develop transportation plans and improvement 

programs, establish transportation funding mechanisms and build, 

maintain, and operate transportation infrastructure and services. 

• The private sector, when contracted by federal, state, or local

governments, may build new roads, provide maintenance on existing 

roads, and supply traffic management equipment and, in recent models, 

design, finance, build, operate, and maintain the roads. 

In general, the federal government leaves many of the decisions about 

specific projects to states and localities, but it partners with these other 

levels of government in overall planning and administration, as well as 

funding the projects. The current framework for federal participation is set 

forth in authorizing statutes, most recently amended by SAFETEA-LU. 

SAFETEA-LU also amended certain requirements governing the way states

and local governments plan and decide upon transportation projects. For 

example, the requirements describe various planning tasks that states and

metropolitan planning organizations must perform to include (1) 

developing long- and short-range transportation programs and plans, (2) 

specifying financing for the transportation programs and projects 

Page 12 GAO-07-920 Surface Transportation
identified, and (3) involving a wide range of stakeholders in the process 

that emphasizes cooperation and coordination. State and local government

agencies must operate within the requirements set forth by SAFETEA-LU 

to receive federal funds.

Three broad factors limit efficient use of the road network. First, the 

design and operation of existing road networks fail to adapt to changing

uses. Second, the traditional funding structure does not provide incentives 

for the efficient use of roads. Third, the current investment decisionmaking process has a limited focus on selecting projects that may produce 

the highest net social benefits. 

It is increasingly apparent that a considerable part of the nation’s road 

network, particularly in urban areas, was neither designed and built to 

meet today’s traffic volumes, nor has its operation changed sufficiently to

better meet current usage patterns. 

Three Broad Factors 

Inhibit Efficient Use 

of Roads 

Road Network’s Design 

and Operation Fail to 

Adapt to Changing Uses 

• Problems with design. A road’s design, which may have been adequate for

a lower level of use, can create problems as traffic volumes increase. For 

example, existing exit and entrance ramps on freeways may be very short, 

allowing exiting vehicles little distance to move out of a fast-moving lane 

of traffic and allowing entering vehicles little distance to accelerate to 

highway speed. When the traffic volume is low, drivers exiting and 

entering the freeway may have ample time to shift lanes and maintain or 

increase speed, but as traffic volume increases, they may be unable to do

so. As a result, the interchange can become a choke point. Similarly, some 

older roads do not have separate lanes for left-turning traffic at the 

intersection and, at peak hours, drivers making left turns can block 

considerable traffic behind them. 

• Problems with operations. Growing populations, longer trips, and other 

demographic and socioeconomic trends have contributed to changes in

traffic volume and driving patterns, but operation of the road system has 

not necessarily changed to deal with these volumes or patterns. For 

example, because each local jurisdiction generally manages and operates 

its own streets, it may not have incentives to coordinate the timing of 

traffic signals on roads that cross many jurisdictions. As a result, the 

timing of traffic signals on these corridors may not operate in such a way 

to minimize the number of stops a driver would have to make. At peak 

hours, as traffic volumes increase, more traffic backs up at each stop, and 

traffic flow breaks down, creating a significant source of delay for drivers 

in their daily use of the major street system. 

Page 13 GAO-07-920 Surface Transportation
Moreover, when a temporary disruption on the road occurs, these design 

and operation problems can hamper a road’s ability to recover quickly.

There are three main types of temporary disruptions—vehicle incidents, 

weather-related events (such as heavy rain), and work zones.9

 These 

temporary disruptions, which can cause congestion even on a road with 

low traffic volume, can grind the traffic on a whole road network to a halt 

if they occur on roads that already have design problems such as no leftturn lanes, or operational problems such as poorly timed traffic signals. 

According to FHWA, these three types of temporary disruptions account 

for about 50 percent of all congestion delays, with 25 percent of all delays 

related to vehicle incidents, 15 percent to weather, and 10 percent to work 

zones. As figure 3 shows, the impact of a vehicle incident is magnified 

depending on how much of a roadway is affected. Compounding the 

effect, local transportation agencies often do not have an effective 

protocol to share information quickly and may lack a coordinated 

approach to manage such incidents, such as who is responsible for 

clearing an accident, and how to do so. The difficulty of predicting the 

effect that such incidents will have on the time it takes shipments to 

traverse the road network can also induce freight operators to factor 

additional time into their schedules or businesses into warehousing 

additional inventory, thereby increasing the cost of conducting business. 

 9

One major FHWA program to mitigate work zone disruptions is the Highways for LIFE 

program. This program focuses on construction techniques, such as the use of 

prefabricated bridge and pavement elements and scheduling construction at night or on

weekends that can reduce road closures, thereby limiting the impact of these events. 

Page 14 GAO-07-920 Surface Transportation
Figure 3: Percentage of Highway Capacity That Is Reduced When Vehicle Incidents Occur 

Crash blocking one lane: 50% decrease in highway capacity Disabled vehicle on shoulder: 15% to 20% decrease in highway capacity

Source: GAO analysis of FHWA information.

Note: The percentages are estimates for three-lane highways only and may vary with actual 

circumstances. 

Traditional Funding 

Structure Does Not 

Provide Incentives for 

Efficient Use of Roads 

The federal and state transportation revenue-raising structure, which 

collects the majority of revenues through fuel taxes and other user fees, 

does not convey to drivers the full costs of their use of the road. These 

taxes and fees—-such as fuel taxes or sales taxes—are not tied to the time 

when drivers actually use the road or which road they use. For example, 

the tax rate on gasoline is the same regardless of whether users drive in 

congested or uncongested periods. Except for these taxes and fees, drivers 

may generally perceive the use of the road as “free.” However, the use of 

roads during congested periods can impose a variety of costs on other 

drivers and the society at large, such as the following: 

Page 15 GAO-07-920 Surface Transportation
• When drivers enter an already crowded road, this creates even longer 

delays for everyone and thus an additional cost for everyone in loss of 

valuable time stuck in traffic. 

• Drivers may more likely get into an accident on a congested road. The 

greater potential of an accident occurring may create more uncertainty in

predicting travel time, increasing costs for the traveling public and 

businesses because they need to schedule additional time to allow for 

possible delays. 

• Research shows that vehicles emit substantially more air pollution per 

mile when driven in congested traffic than in uncongested situations, 

which is a cost to society and is borne more heavily by the public living 

near the congested corridors. 

The existing revenue-raising structure provides no incentive for users to 

take these costs into account when making their driving decisions. From 

an economic perspective, a mechanism is needed that gives users price 

incentives to consider these costs in deciding when, where, and how to 

drive. Because the existing structure does not reflect the economic, social,

and environmental costs of driving at peak periods, drivers who may have

flexibility to share rides, use mass transit, use more indirect but less 

congested routes, or defer their trips to uncongested times have no 

financial incentives to do so. Without such incentives, the transportation 

system will be headed for more frequent occurrences of congestion that 

last longer, resulting in more time spent traveling, greater fuel 

consumption, and higher emissions in the long run. 

The final factor inhibiting efficient use of the road network relates to the 

ability to identify—and put in place—infrastructure investments that are 

most likely to be efficiently used. Making the best use of scarce resources

for transportation infrastructure requires a process that allows decision 

makers to identify which investments would produce the highest net 

social benefits; however, this information is limited in the current 

decision-making process. Two characteristics inhibit decisions on this 

basis. Specifically, the current process is highly compartmentalized by 

transportation mode and is not driven by systematic economic analysis. 

Both characteristics, as explained below, can lead to investment decisions 

that, from the standpoint of making the transportation network as efficient 

as possible, produce suboptimal results. 

Current Investment 

Decision-Making Process 

Has a Limited Focus on 

Selecting Projects That 

May Produce the Highest 

Net Social Benefits 

Page 16 GAO-07-920 Surface Transportation
• Funding is compartmentalized by transportation mode. Many 

transportation experts maintain—and our past work10 tends to confirm—

that the current structure of funding at the federal and state level is highly

compartmentalized, or stove-piped. Funding is often tied to certain 

programs or types of projects, such as highways or transit, and it has also

been increasingly designated for specific local uses.11 This structure 

provides state, regional, and local agencies with little incentive to 

systematically compare the trade-offs between investment alternatives 

across different modes of transportation. As a result, they may choose to 

finance projects that do not produce the highest estimated social benefits 

to society. By definition, projects that produce the highest estimated social

benefits further the efficient use of scarce resources for transportation 

infrastructure.12 For example, due to the stove-piped funding, decision 

makers may decide to fund a smaller mass transit project instead of a highoccupancy toll (HOT)13 lane network project, which could require 

additional funding designated for other programs. The HOT lane network 

project, despite its potentially higher cost than the smaller transit project, 

could create a more efficient use of the road by allowing single drivers to 

pay to use the existing car pooling lanes and therefore provide greater 

overall public benefits. In addition, the toll revenue collected from the 

paying drivers can be used to subsidize the riders of existing transit lines 

 10GAO, Highway and Transit Investments: Options for Improving Information on 

Projects’ Benefits and Costs and Increasing Accountability for Results, GAO-05-172 

(Washington, D.C.: Jan. 24, 2005). 

11See also, Thomas M. Downs, “Is There a Future for the Federal Surface Transportation

Program?”, Journal of Transportation Engineering 131, 6 (June 2005), and Ann Brach and 

Martin Wachs, “Earmarking in the U.S. Department of Transportation Research Programs,”

Transportation Research Part-A 39 (2005). Brach and Wachs observed that transportation 

research funds have been increasingly earmarked for specific institutions. 

12Clifford Winston and Ashley Langer, “The Effect of Government Highway Spending on

Road Users’ Congestion Costs,” Journal of Urban Economics 60 (2006), argued that the

current system allocates federal funding and state funding based partly on formulae which

place great weight on the size of a state’s road system and on a jurisdiction’s road mileage, 

respectively. To allocate resources more efficiently, this system would need to be revised 

to be based more on the level of congestion and, even then, it is still not as effective as 

congestion pricing. 

13“HOT” lanes allow drivers who drive by themselves to pay to use less congested carpool

lanes and thereby speed up their trips. 

Page 17 GAO-07-920 Surface Transportation
and, therefore, potentially increasing ridership and further reducing 

congestion.14

• Economic analysis does not drive decisions. Decisions about what 

projects to fund are seldom subjected to rigorous economic analysis. Our 

prior work found that economic analysis, such as benefits and costs 

analysis, is not systematically used in the decision-making process.15 Many 

tools and methods to perform economic analysis are available, and these 

tools have the potential to provide decision makers with valuable 

information such as potential social, environmental, and safety effects of 

alternative transportation projects. For example, benefit and cost analyses

integrate and monetize the quantifiable benefits and costs of each 

alternative, thereby allowing decision makers to more easily compare 

different investment alternatives. In most instances, however, such 

analyses are not performed and, if they are, they are often just one 

factor—and not necessarily the most important one—that decision makers 

consider. The limited extent to which formal economic analysis is 

systematically used makes it difficult for decision makers to assure they 

are funding projects that best ensure the efficient use of scarce resources. 

Our review of transportation literature and our discussions with 

transportation officials identified two main categories of congestion 

mitigation techniques that are currently being used to make the current 

infrastructure more efficient. The first category includes techniques that 

enhance existing road capacity through better operations and 

transportation technology. These types of congestion mitigation 

techniques range from incident response vehicles that more quickly 

restore traffic flow after accidents to the deployment of transportation 

technology, such as metering traffic onto freeways and optimizing the 

Various Techniques 

Have Been Developed 

to Make the Current 

Infrastructure More 

Efficient 

 14California, Colorado, Florida, Texas, Virginia, and Washington all have HOT lanes or have 

projects planned that will use variably priced tolls to alleviate congestion by managing the

level of traffic. All of these states have received grants under FHWA’s Value Pricing Pilot 

Program to either develop or implement the projects. 

15GAO, Surface Transportation: Many Factors Affect Investment Decisions, GAO-04-744 

(Washington, D.C.: June 30, 2004). 

Page 18 GAO-07-920 Surface Transportation
timing of traffic signals that can improve traffic flow.16 For example, 

Washington State, recognizing that vehicle crashes can significantly 

reduce the capacity of freeways, implemented an incident response 

program consisting of camera surveillance, private tow companies, and 

roving patrol vehicles to enable a rapid response to incidents. To help 

clear incidents even faster, Washington State has a “steer it, clear it” law 

that requires drivers to move their vehicles off a main freeway if it is 

possible to do so. Another example of enhancing capacity through 

operations is utilizing access management, which is a set of techniques 

designed to control and limit vehicle access to highways, major arterials, 

and other roadways. For instance, transportation agencies have 

implemented access management techniques to improve traffic flow and 

reduce delays by increasing spacing between interchanges and redesigning 

intersections. 

The second category of congestion mitigation techniques involves 

reducing congestion by influencing driver behavior on when and where to

drive. These techniques range from employer transit subsidies and flexible

work schedule programs to congestion pricing. By providing transit 

subsidies or flexible work schedules, employers make it easier for drivers 

to drive during less congested times or not drive to work at all. Congestion

pricing also attempts to influence driver behavior by charging drivers 

higher prices during peak hours. As of today, a major example of states 

implementing road pricing techniques on highways in the United States is 

the converting of high-occupancy vehicles (HOV) lanes to HOT lanes, 

which are priced lanes that offer drivers of vehicles that do not meet the 

occupancy requirements the option of paying a toll to use lanes that are 

otherwise restricted to HOV vehicles.17 Another form of congestion pricing 

is called cordon pricing, which charges a fee for any vehicle that enters a 

congested area, such as a city center. Although this type of congestion 

pricing has only been implemented in foreign countries to date, cities in 

 16Signal timing is one of many Intelligent Transportation System (ITS) technologies. ITS 

technologies use communications, electronics, sensors, and computer hardware and

software to improve the performance and safety of freeways, roads, and transit systems. 

Other congestion mitigation techniques using ITS technologies include traffic cameras, 

message signs, traveler information Web sites, traffic sensors, ramp meters, and electronic 

toll collection systems. See GAO, Highway Congestion: Intelligent Transportation 

Systems’ Promise for Managing Congestion Falls Short, and DOT Could Better Facilitate

Their Strategic Use, GAO-05-943 (Washington, D.C.: Sept. 14, 2005). 

17For example, the occupancy requirement for some HOV lanes is at least three people; in 

these instances, a HOT lane would allow a vehicle with two people to use the lane if the 

driver pays a toll. 

Page 19 GAO-07-920 Surface Transportation
the United States such as New York and San Francisco are studying the

potential implementation of cordon pricing. 

These various techniques can often be used in tandem to produce a more

robust congestion mitigation strategy. Figure 4 depicts a cross section of 

eight different techniques that both enhance existing capacity and 

influence driver behavior and demand. The strategies shown range from 

signal timing and extensive use of HOV and HOT lanes to workplace 

efforts designed to reduce traffic or shift it to less congested times of the 

day. For a more detailed list of congestion mitigation techniques see 

appendix II.

Page 20 GAO-07-920 Surface Transportation
Figure 4: Select Congestion Management Techniques that Enhance Capacity and Influence Driver Behavior and Demand 

HOT

LANE

Traffic signal timing

Transit and car pool lanes

Telework policies

LANE

HOT

LANE

HOT

HOT

LANE

Traffic signal timing –

coordinating the timing 

of a series of traffic 

signals along an 

arterial to reduce stops

and move vehicles at a

uniform speed. 

Incident management 

program – a planned 

and coordinated 

program to detect, 

respond to, and 

remove traffic incidents

to reduce congestion.

Work zone 

managment – using 

highway shoulders

and crossover lanes

during construction 

to maintain road 

capacity. 

Transit and car pool 

lanes – dedicating 

lanes for buses and 

car pools on freeways

and arterials thus

increasing capacity by 

reducing single- occupancy vehicles. 

Traveler information – 

providing up-to-theminute traveler 

information, such as

travel times, roadwork, 

accidents, and alternative routes via cell 

phone or Web access. 

HOT lanes – a priced 

lane that offers

single-occupancy 

vehicle drivers the 

option of paying a toll 

to use lanes that are otherwise restricted. 

Worksite flextime – 

flexible arrival and 

departure times

to/from work that 

encourage employees

to avoid most 

congested travel times. 

Telework policies – 

allowing employees to 

work at home a certain number of workdays, which results in less

work-related travel. 

1

1

2 Incident management

7 High-occupancy toll (HOT) lanes

5

5

6 8

2 3 4

4

LANE

HOT

LANE

HOT

7

Roadwork

Ahead

3 Work zone management

6 Worksite flextime

TRAVEL 

INFO

CALL 511

TRAVEL

INFO

CALL 511

8 Traveler information

Congestion mitigation techniques that influence driver behavior

Congestion mitigation techniques that enhance capacity

Page 21 GAO-07-920 Surface Transportation
Although studies and evaluations of specific projects that have 

implemented congestion mitigation techniques vary in quality and scope,

transportation research has generally shown that such techniques have the 

potential to help reduce congestion and make better use of existing 

transportation infrastructure capacity.18 Specifically, some examples of 

studies and evaluations suggest that techniques such as incident response 

programs, signal timing coordination, and HOT lanes help maximize 

existing capacity by providing improved traffic flows, reduced delays, and 

increased vehicle speeds. Following are examples: 

• In Washington State, transportation officials have monitored the results of 

their incident response program and found that the average time to clear 

incidents has decreased from 33 minutes to 16 minutes, which in turn 

reduced the amount of time that the incident was creating congestion by 

about half. 

• A study of a traffic signal optimization project in the Denver area showed 

that the project resulted in a 13 percent reduction in vehicle travel times 

and a 17 percent improvement in travel speed. 

• An evaluation of the Express (HOT) lanes for the State Route 91 project in

Orange County, California, showed that although the HOT lanes represent 

only 33 percent of the capacity of State Route 91, they carry an average of

40 percent of the traffic during peak travel times (see fig. 5). 

 18As we reported in 2005 in our review of ITS projects, though studies of ITS projects have 

found positive impacts, most of the studies we reviewed did not include information on the 

cost effectiveness of the ITS project, such as benefit-cost analyses (see GAO-05-943). 

Page 22 GAO-07-920 Surface Transportation
Figure 5: Express Lanes and General Purpose Lanes on State Route 91 in Orange

County, California

In our review of transportation research and discussions with

transportation officials, we found that congestion mitigation techniques 

are most effective when tailored to the particular situation. For example, 

because they encourage some additional traffic from single-occupancy 

vehicles, HOT lanes have generally been used in cities with congested 

freeways and underutilized HOV lanes. Similarly, because it discourages 

vehicles from entering a central urban zone, cordon pricing is used in large 

cities with developed transit systems that provide alternative modes of 

travel to the city centers. In addition, congestion mitigation techniques 

have been found to be more effective when used in combination. For 

example, the following techniques have been effective:

Source: Caltrans.

General

purpose lanes

Express lanes

• When a major accident occurs on a freeway, message signs with traffic 

information can be used to divert traffic to a parallel arterial, while 

incident response vehicles work to clear the freeway. 

• With the installation of ramp meters, lines of queuing vehicles sometimes 

can back up onto local arterials. To help address this problem, other 

techniques, such as optimizing signal timing, can be used to reduce the 

Page 23 GAO-07-920 Surface Transportation
rate at which vehicles enter the freeway ramp. 

• Electronic toll collection technology can be used to collect tolls from HOT 

lane vehicles. This significantly reduces the delays caused by vehicles 

stopping to pay at toll booths. 

At locations we reviewed, officials chose varying congestion mitigation 

techniques but tended to implement them with a similar three-pronged 

approach: (1) changing planning and related processes to give them higher

priority, (2) developing creative mechanisms to fund them, and (3) 

collaborating with multiple stakeholders to put them in place. However, 

officials told us that many of the congestion mitigation techniques they 

used had been able to provide benefits only at the margins because several

persistent issues prevented them from using these congestion mitigation 

techniques more fully. These issues ranged from resolving jurisdictional 

authority to identifying sources that would provide sufficient funding for 

larger-scale projects. 

State and local transportation officials we interviewed told us that they are 

changing their transportation planning priorities to reflect a greater 

emphasis on congestion mitigation techniques. To make these congestion 

mitigation techniques a priority, officials have established new goals and 

priorities, modified their project selection process, restructured their 

organizations, and adopted new policies and initiatives. 

Officials from the transportation agencies we visited reported establishing 

goals related to using the existing road infrastructure more efficiently by

implementing congestion mitigation techniques. They generally said they

had incorporated these goals into both their long-range and short-range 

transportation plans.19 Table 1 shows examples of these goals identified in 

their plans. Our review of these plans showed that the new goals reflect a 

shift in emphasis—that is, a movement from the traditional approach that 

has been and, in many cases still is focused on the construction of new 

Transportation 

Decision Makers Are 

Using Similar 

Approaches for 

Implementing 

Congestion Mitigation 

Techniques, but 

Challenges Exist 

Officials Report Giving 

Congestion Mitigation 

Techniques More Priority 

in Their Transportation 

Planning 

Setting Goals That Incorporate 

Congestion Mitigation

 19Long-range plans identify transportation needs for the next 20 years. Short-term 

transportation plans, called Transportation Improvement Programs (TIP), describe 

projects selected to support long-range transportation plan goals. Federal law requires that, 

within these plans, each metropolitan planning organization consider at least seven factors, 

one of which is to promote efficient system management and operation. 

Page 24 GAO-07-920 Surface Transportation
road capacity or the maintenance of existing road infrastructure, to a 

greater emphasis on managing the system more efficiently.

Table 1: Examples of Long-range and Short-range Transportation Plans at Locations GAO Visited 

Location Added emphasis on managing existing infrastructure more efficiently 

San Diego, CA Long-range plan (through 2030) now includes a focus on making the best use of the existing transportation

system and a shift in emphasis from expanding the system to managing demand. The plan highlights such

techniques as improving traffic information provided to drivers, continuing the current incident management

program, developing new HOT lanes, improving transit and telework programs, and continuing their van pool

and car pool programs. 

Orlando, FL Long-range plans include a goal of better managing and operating the system, specifically prioritizing incident

management programs, and linking land-use strategies with the transportation plan. 

Seattle, WA The City of Seattle’s Comprehensive Plan (the 20-year policy plan) recognizes that expanding streets and roads

to accommodate cars is generally unproductive. In addition, opportunities to widen or construct new streets in

Seattle are extremely limited because of its built-out, urban environment. The plan suggests increasing the use

of transit, walking, bicycling, carpooling, and other alternatives, such as addressing parking in the city. 

Denver, CO Short-range transportation plan now includes funding for intelligent transportation systems and demand

management programs, such as improving ramp metering for entering highways, improving signal timing on

roads, and expanding outreach to employers to promote telework and flextime work. 

Bellevue, WA Long-range planning program routinely includes projects that examine how land-use decisions influence system 

performance and their short-range transportation plan includes using operations methods, such as real time 

traffic flow and ITS applications to optimize traffic flow. 

Source: GAO.

Some transportation agencies we visited modified their transportation 

project selection process to provide greater emphasis to projects that use

congestion mitigation techniques. For example, in considering which 

projects to select for funding, the metropolitan planning organization for 

the Denver region now awards points to projects that use certain 

congestion mitigation techniques, such as installing left-turn lanes, 

promoting car pools, coordinating traffic lights, or managing incidents. 

Officials said they hope awarding points will provide incentives for local

planners to include such congestion mitigation techniques in their 

projects. Several other metropolitan planning organizations we 

interviewed, such as Virginia’s Hampton Roads Planning District 

Commission, had modified their project selection process to promote 

projects that have a regional objective, which prior to these changes, 

would have had a low probability of funding under the previous allocation 

program. Officials said that by modifying the selection process, they can 

better align which projects are selected to their overall goal of using the 

existing infrastructure more efficiently. 

Modifying Project Selection 

Process to Emphasize 

Congestion Mitigation Goals 

Page 25 GAO-07-920 Surface Transportation
To ensure that their organizations are aligned with transportation goals, 

transportation agencies in a number of locations we visited had 

restructured their organizations by creating new departments or 

committees. For example, Seattle’s metropolitan planning organization, 

the Puget Sound Regional Council, created a new team dedicated to 

working on projects that improve the operations of the transportation 

system. This department was designed to work with other transportation 

agencies to improve mobility through implementing demand management, 

improving operational efficiency, and identifying capacity solutions at the

corridor and regional planning levels. Orlando’s metropolitan planning 

organization created a management and operations department and a 

subcommittee composed of local planners and traffic engineers, which is 

responsible for sustaining and increasing funding for projects that use 

congestion mitigation techniques, such as incident management, and 

strategies to manage driver behavior. 

Restructuring Organizations to 

Align with Transportation 

Planning Goals 

At some locations we visited, greater use of congestion mitigation 

techniques was also spurred by state policies. We found the following 

examples: 

Adopting Policies or 

Regulations That Promote 

Congestion Mitigation 

Techniques • In 1991, Washington State’s legislature passed a law designed to reduce 

traffic congestion, reduce air pollution, and petroleum consumption by 

requiring metropolitan planning organizations to foster employer-based 

programs that decrease the number of commuting trips made by people 

driving alone. Since the law was passed, the number of vehicle trips has 

dropped statewide. In the central Puget Sound region, where Seattle is 

located, the number of vehicle trips made during the morning commuter 

hours has dropped by 14,000, reducing peak travel delay by an estimated 

11.6 percent, on average, each weekday morning in the region.

• California requires all urbanized areas to monitor the performance of the 

transportation system, develop programs to address short-term and longterm congestion, and better integrate transportation and land-use planning 

through congestion mitigation programs. In response, San Diego’s 

metropolitan planning organization, the San Diego Association of 

Governments, developed a congestion mitigation program that encourages

the use of strategies other than road widening or extensions to address 

congestion at low costs, such as encouraging transit use, establishing 

programs for car pools, and teleworking programs. 

• Oregon through its Interchange Area Management Plan rules has 

introduced new requirements that stipulate local governments jointly 

manage access on crossroads in the vicinity of interchanges. Specifically, 

regulations require that new intersections at crossroads be placed at least 

Page 26 GAO-07-920 Surface Transportation
1,320 feet from the interchange ramp terminals, thereby reducing the

potential backups on the highway exit ramps. 

Transportation officials told us that the mode-specific, or stove-piped 

funding structure for transportation projects, together with a general lack 

of resources for transportation projects, constrains their ability to invest in

congestion mitigation techniques. As a result, they said, they often have to

find alternative methods to supplement traditional funding sources. The 

methods they cited included imposing additional tolls, local taxes, or 

development impact fees; developing partnerships with private industry;

and designating separate funding. 

A number of state and local governments in the locations we visited had 

imposed additional tolls, local taxes, and development impact fees to 

provide funding for the implementation of congestion mitigation 

techniques. Officials said they had done so because traditional funding 

sources were not generating sufficient resources. Many of these revenue

sources were focused in a specific region and were geared toward 

implementing specific congestion mitigation techniques. For example, 

voters in the San Francisco region passed an increase in toll fees on the 

region’s seven state-owned bridges to support the Regional Traffic Relief 

Plan, which funds such projects as expanding transit options, as well as 

improving transit connections and several freeway bottlenecks. Several 

other regions passed sales, property, or gasoline taxes. For example, San

Diego passed a half-cent sales tax to implement a number of congestion 

mitigation techniques to help improve traffic congestion on the most 

highly congested corridors in the region. This included funding for new 

HOV and managed lanes along highways, new connectors to the highways, 

and transit improvements. 

Some localities generated additional transportation funding through 

another source—development impact fees.20 They used this approach 

particularly when new development had a significant effect on the current

road network. Florida, for example, has passed a law that regulates largescale developments that have substantial impacts on the transportation 

system. This program allows local governments to assess new 

developments and assign fees related to their impact on the local 

Agencies Report 

Developing New Methods 

to Fund the Use of 

Congestion Mitigation 

Techniques 

Imposing Tolls, Local Taxes, or 

Development Impact Fees 

 20Development impact fees are payments made by developers for the cost of additional

infrastructure necessary as a result of the new development.

Page 27 GAO-07-920 Surface Transportation
infrastructure, including transportation. Between 1993 and 2004, this 

program provided local governments with $2 billion statewide for efforts 

to improve transportation infrastructure, including ways to reduce 

congestion.

Transportation agencies reported developing partnerships with private 

industry to help fund congestion mitigation techniques. According to 

transportation experts, working with private companies can offer a 

number of benefits for the transportation agency, such as expediting the

project schedule, reducing costs, and providing access to private funding

sources. Examples we identified included the following: 

Developing Partnerships with 

Private Industry 

• In 1995, California’s Department of Transportation partnered with a 

private company to develop a four-lane, 10-mile toll road of HOT lanes in 

the median of a freeway (State Route 91) in Orange and Riverside 

Counties. The company financed, managed, and collected revenues from 

the variable-priced tolls on the HOT lanes. In 2003, Orange County 

Transportation Authority purchased the HOT lanes and is now managing 

them. 

• In Virginia, a private company is installing equipment to collect traffic data 

on all of the state’s highways and some major arterial roads, which could

be used for local intelligent transportation systems and for transportation 

planning. The company will have permission to sell the information to 

private companies and individual drivers but will also allow the local

jurisdictions to obtain and use the data for free. 

• State Farm Insurance entered a partnership with the Florida Turnpike to 

provide funding for the State Farm Safety Patrol—a 24-hour roadway 

assistance and service program that provides free driver assistance to 

motorists along Florida’s Turnpike. State Farm provides funding annually

to the Florida Turnpike and, in exchange, places advertisements on the 

State Farm Safety Patrol vehicles. These vehicles help improve mobility by 

minimizing the duration of incidents, assisting disabled drivers, and 

removing road debris—all of which can help reduce vehicle crashes. (See 

fig. 6.) 

Page 28 GAO-07-920 Surface Transportation
Figure 6: Florida Road Ranger Incident Response Vehicle 

Some transportation agencies we visited have designated a certain amount 

of funding out of their traditional transportation funding for congestion 

mitigation techniques. Officials at these agencies said doing so ensures 

that congestion mitigation projects receive some funding. For example, 

each year from 2007 to 2011, Denver’s metropolitan planning organization

plans to designate $20 million to $23 million of its state and federal funding

for congestion mitigation techniques such as van and car pool programs 

and traffic signal improvements. Similarly, the Orlando metropolitan 

planning organization has designated $2 million annually of its state and 

federal funds for its intelligent traffic system program. Orlando officials 

said that they have decided to increase this funding to $4 million annually 

in the future because of the potential for improving efficiency.

Transportation agencies we visited reported working with multiple 

partners to implement congestion mitigation techniques. According to 

officials, the success of these techniques depends on such coordination. 

For example, in Washington State, the Department of Transportation and

the state patrol established standard operating procedures for such 

matters as data sharing, traffic management, and incident response. In 

Source: Florida DOT.

Designating Specific Funding 

within Existing Resources 

Transportation Agencies 

Are Collaborating with 

Multiple Stakeholders 

Page 29 GAO-07-920 Surface Transportation
several other states we visited, transportation agencies have established a 

goal of clearing a highway accident within 90 minutes of when the first 

responder arrives. Coordinating signal timing across jurisdictions was 

another technique for which transportation officials said collaboration 

was important. 

We found a number of examples where transportation agencies participate 

in multijurisdictional groups to help ensure that transportation plans 

encompass regional and comprehensive perspectives. For example, the 

Central Florida Metropolitan Planning Organization Alliance was created 

to coordinate regional transportation planning. This council consists of six 

metropolitan planning organizations that include ten counties in Central 

Florida, and its membership includes metropolitan planning organizations’ 

board members and staff, and state transportation staff. Similarly, several 

metropolitan planning organizations that we visited have committees 

focused on regional planning. Participants on these committees include 

representatives from regional jurisdictions and transit agencies. 

While officials at the locations we visited were making greater use of these 

congestion mitigation techniques, they also said a number of issues 

prevented them from implementing these techniques to the extent desired. 

As a result, they said, that congestion mitigation techniques they were 

implementing could provide only marginal improvement to the efficiency 

of the road network. Issues they cited included the following: 

Persistent Issues Keep 

Congestion Mitigation 

Techniques from Having 

Greater Effect 

• Lack of authority. Officials of local government agencies said some 

congestion mitigation techniques need to be implemented by federal or 

state agencies and cannot be legally implemented by local transportation 

agencies. For example, while cities implement congestion mitigation 

techniques like intelligent transportation systems, they generally cannot

implement large-scale techniques such as congestion pricing on major 

state highways. Being able to integrate congestion mitigation techniques 

comprehensively, they said, may be critical for seeing improvements on 

the road network. 

• Barriers to obtaining additional funding. Finding alternative funding for 

projects can be difficult, officials said. Efforts to impose new charges, 

such as toll fees on roads, may be opposed by the public, since the public 

can feel as though it is being charged twice for use of the roads. In some 

states, funding sources such as development impact fees are not 

authorized by law, and those that are authorized by law have a number of 

provisions on how local governments can use revenues that may affect 

Page 30 GAO-07-920 Surface Transportation
their ability to use these fees to their fullest. 

• Lack of complete and reliable data. The lack of complete and reliable data

hinders the ability of transportation officials to make fully informed 

decisions about implementing congestion mitigation techniques. For 

example, data about traffic flow throughout the day, rather than at a single

time, are crucial to produce valid representations of travel needs and 

problems. However, reliable and complete data are not always available—

which can result in forecasting errors or limit the ability to conduct 

outcome evaluations.21

• Difficulties in resolving jurisdictional issues. Many transportation 

officials we interviewed noted the struggle to align different perspectives 

when trying to work regionally on projects. Often, they said, there are 

competing ideas of which jurisdictions should be responsible for the 

management and funding of projects that cross boundaries. 

• Limitations of the current funding and decision-making process. 

Transportation officials noted that the current funding and decisionmaking processes, with their orientation to particular modes of 

transportation and their limited reliance on analysis of the costs and 

benefits of various transportation alternatives, provide a built-in 

preference for projects that build or maintain transportation infrastructure 

rather than try to use existing structure more efficiently. Although 

congestion mitigation techniques may produce the highest estimated 

social benefit, in times of constrained budgets, many officials said that 

obtaining money for congestion mitigation projects can be difficult. 

 21FHWA is working with the National Transportation Operations Coalition (NTOC) and 

state and local governments on an ongoing project to develop a common set of operations 

performance measures and definitions. FHWA officials stated that piloting of the measures 

will take place as part of a National Cooperative Highway Research Program (NCHRP) 

study in 2007, with results expected in early 2008. 

Page 31 GAO-07-920 Surface Transportation
Various strategies exist for increasing the efficient use of infrastructure, 

according to the officials and experts we talked with and the studies we 

reviewed.22 These strategies include applying congestion mitigation 

techniques on a regional basis and linking federal-aid highway funding to 

performance. We grouped these strategies by the level of government best 

suited to consider and implement them, given their current authorities, 

roles, and responsibilities (see fig. 7). In some cases, all levels of 

government would need to be involved in implementing the strategy; in 

other cases, the federal government or a state or local government would 

be most appropriate to implement the strategy. These strategies are not 

mutually exclusive and ideally would be implemented in a comprehensive 

manner, according to transportation research and transportation officials

and experts we interviewed. 

Various Strategies 

Exist for Increasing 

the Efficient Use of 

Infrastructure 

 22Institute of Transportation Engineers, Action Kit: Immediate Solutions for 

Transportation Operational Issues (Washington, D.C.: 2005); American Association of 

State Highway and Transportation Officials, Future Needs of the U.S. Surface 

Transportation System (February 2007); Cambridge Systematics, Traffic Congestion and

Reliability: Linking Solutions to Problems (Cambridge, MA: July 19, 2004); Cambridge

Systematics, Traffic Congestion and Reliability: Trends and Advanced Strategies for 

Congestion Mitigation (Cambridge, MA: Sept. 1, 2005); Transportation Research Board,

Performance Measures to Improve Transportation Systems: Summary of Second

National Conference (Washington, D.C.: 2005); Transportation Research Board, Linking 

Transportation and Land Use: A Peer Exchange (Washington, D.C.: July 2006). 

Page 32 GAO-07-920 Surface Transportation
Figure 7: Strategies for Making More Efficient Use of Existing Infrastructure 

We identified three strategies that would likely require the attention and 

involvement of all levels of the government to be successfully 

implemented. These strategies are (1) considering how the private sector 

can be used in managing existing road infrastructure, (2) determining the 

feasibility of expanding use of the user-pay concept for managing demand 

and generating revenue for transportation investments, and (3) developing

a systematic performance-based management approach to increase the 

accountability of public expenditures and to link performance to 

investment decisions. 

Public policymakers at the federal, state, and local levels could consider 

how the private sector can be used in the operation and management of 

the existing road infrastructure. Proponents believe that expanding the 

use of public-private partnerships could take advantage of the private 

sector’s ability to manage assets with the intended outcome of providing a 

more efficiently operated road network. Private companies, driven by the 

need to make a return on investment, are incentivized to manage assets 

and provide services in efficient ways. Specifically, how efficiently they 

Strategy

Consider how the private sector can be used in managing 

existing infrastructure. 

Expand the use of the user-pay concept. 

Measure results and manage with them in mind. 

Implement a combination of supply-related and 

demand-related techniques.

Apply congestion mitigation techniques on a

regional basis. 

Integrate transportation planning more fully with landuse planning.

Provide leadership to build support for implementing 

congestion mitigation techniques.

Link federal-aid highway funding to performance. 

Increase flexibility for local decision making for 

implementing innovative solutions. 

Support projects that provide national public benefits. 

State and local

governments

Federal

government

Source: GAO.

Three Strategies Crosscut 

All Levels of Governments 

Consider How the Private 

Sector Can Be Used in 

Managing Existing 

Infrastructure 

Page 33 GAO-07-920 Surface Transportation
operate an asset directly affects the profits they derive from their 

investments and is directly linked to the overall success of the company. If 

a partnership is designed and structured appropriately, transportation 

agencies could leverage this incentive. To date, public-private partnerships 

in the United States have often been used to manage toll roads, such as 

State Route 91, as described earlier. In addition, a recently emerging 

public-private partnership model is where the private sector is awarded, 

through a long-term lease agreement, the concession to operate, maintain, 

and collect tolls on existing publicly owned highways. In return for the 

revenues collected by the tolls, these concessions often require that the 

private companies meet established performance standards, which can 

include maintaining the condition of the road to a specific standard, and 

allow increasing toll rates on an annual basis in line with inflation.23

The federal government and some state governments have also shown 

interest in developing public-private partnerships to support research and 

development of advanced technology that can help enhance the capacity 

of the existing road infrastructure. Transportation experts argue that 

advanced technology could potentially allow for more efficient use of the 

road network by improving safety and increasing the availability of 

transportation data to drivers and transportation planners. An example of

governments partnering with private industry in supporting research and 

development of advanced technology is the Vehicle Infrastructure 

Integration (VII) program. The VII program uses technology installed in 

the road infrastructure and the individual vehicle to establish vehicle-tovehicle and vehicle-to-roadside communications (see fig. 8). This system 

would use vehicles as collectors of real time traffic information and more 

complete data from highways and arterial roads, which would be 

processed and distributed to drivers, transportation planners, and traffic 

managers. In 2004, the federal government, the American Association of 

State Highway and Transportation Officials, 10 state departments of 

transportation, and several vehicle manufacturers24 formed an informal VII 

working group to examine the feasibility of widespread deployment and to 

establish an implementation strategy. The VII coalition, which is made up 

 23See our forthcoming report on public-private partnerships that will discuss in further 

detail the potential benefits and significant risks, and steps that must be taken to protect

the public interest. This report is estimated to be published in the fall of 2007. 

24The VII Consortium is a nonprofit organization that is open to all vehicle manufacturers. 

Currently, the consortium membership includes BMW, Daimler Chrysler, Ford, GM, Honda, 

Nissan, Toyota, and VW. 

Page 34 GAO-07-920 Surface Transportation
of the VII working group and the executive leadership team, will report its 

initial findings in 2008. 

Figure 8: Representation of the VII Mobility Applications 

Sources: GAO and DOT.

3 The data received at the RSUs would be sent to an 

aggregation point, where all data would be organized 

and made available to authorized subscribers, 

enabling improved highway safety and more effective 

operation of transportation systems.

Aggregation

point

RSUs Authorized

subscriber

Vehicles would be equipped with a

Global Positioning System (GPS) and 

a transceiver called an On Board Unit 

(OBU). The OBU would collect GPS

data and other sensor data from 

various systems in the vehicle. 

On board

unit

1 Roadway infrastructure, including signalized 

intersections and highways, would be 

equipped with transceivers called Roadside 

Units (RSU). The OBUs in passing vehicles

would anonymously transmit stored data to 

each RSU as they passed by.

2

Roadside

unit

Data

transmission

GPS

data

Sensor

data

Note: The VII information flow differs from the above graphic for many safety applications, where the

data is sent to oncoming vehicles instead of the aggregator, and there is an interface to local signal 

control systems.

The user-pay concept—that is, users should help pay for the infrastructure 

they use—is a long-standing aspect of transportation policy in the United 

States. For instance, federal, state, and local governments have imposed 

excise taxes on motor fuels and other taxes on inputs into driving, such as 

taxes on tires or fees from registering vehicles or obtaining operating 

licenses. These taxes, in turn, are used to pay for highway projects. 

Similarly, some state and local governments charge tolls on certain roads.

These tolls can generate revenues that are consistent with the user-pay 

principle because the driver is directly paying to use that specific road and 

Expand the Use of the User-Pay 

Concept 

Page 35 GAO-07-920 Surface Transportation
the revenues collected from the toll go directly to pay for its construction, 

maintenance, and operation.25

The federal government and some state and local governments are 

studying new alternatives that expand the user-pay concept. At the federal 

level, Congress authorized a road user fees study,

26 which is to examine an 

option to assess highway user fees based on actual mileage driven. The 

final report is scheduled to be submitted to Congress in July 2009. At the 

state level, Oregon’s Department of Transportation tested a pilot program 

that collects a mileage-based fee in lieu of the state gas tax. The program 

used on-vehicle mileage counting devices that record the number of miles 

driven and download mileage information at two gas stations that were 

equipped with mileage readers on the fuel pumps. Drivers are then 

charged a per-mile fee instead of the gas tax. The pilot program ended in 

March 2007, with a final study expected in September 2007.27

A performance-based management approach can increase accountability 

and performance of the existing infrastructure. As we have previously 

reported,28 a performance-based management approach for transportation 

would include establishing performance targets, developing performance 

measures, and enhancing data quality.29 An important element of a 

performance-based approach is evaluating the results of projects or 

Measure Results and Manage 

the Existing Infrastructure with 

Them in Mind 

 25Some states are also increasingly funding transportation projects with alternative 

mechanisms that are not user-pay based. For example, some states are using revenues from

sales taxes and the state’s general fund for transportation projects. 

26The study will be conducted by University of Iowa Public Policy Center. 

27Oregon officials shared some preliminary observations with us in advance of the study’s 

completion. Their preliminary conclusions were that the pilot project’s successes were in 

the areas of zone differentiation (that is the counting devices was able to distinguish with 

accuracy when the car traveled into or out of different preprogrammed zones), mileage 

counting accuracy, transaction administration integration with gas tax collections, and 

mileage data transmission accuracy at the fuel pump. The largest lesson learned is that

retrofitting of existing vehicles with mileage counting technology is highly problematic 

because technology applications for various vehicle makes and models are not 

standardized. 

28See GAO, Marine Transportation: Federal Financing and a Framework for 

Infrastructure Investments, GAO-02-1033 (Washington, D.C.: Sept. 9, 2002); GAO, Freight 

Transportation: Strategies Needed to Address Planning and Financing Limitations, 

GAO-04-165 (Washington, D.C.: Dec. 19, 2003); and GAO-05-172. 

29Transportation asset management, which is a systematic process of maintaining, 

upgrading, and operating transportation assets, is one type of technique that incorporates 

many of the concepts of a performance-based approach. 

Page 36 GAO-07-920 Surface Transportation
conducting outcome evaluations. Such evaluations allow the public to 

hold the government accountable for results. Outcome evaluations also 

offer transportation agencies the opportunity to learn from the successes 

and shortcomings of past projects to better inform future planning and 

decision making. Further, such evaluations help to provide better analytic

information to decision makers. For example, information from outcome 

evaluations could help inform decisions, such as determining whether a 

community would generate higher benefits from investing in a ramp 

metering system on a highway or adding a new lane instead, or whether 

investing in transit provides higher benefits and lower costs compared 

with building a new road. However, outcome evaluations are not required

for highway projects as a condition of federal funding and are not typically

performed. In contrast, SAFETEA-LU requires before and after studies as a 

condition of receiving New Starts funds for completed transit projects.30

For transportation agencies to be able to use a performance-based 

management approach, transportation experts highlighted the importance 

of being able to collect comprehensive and robust traffic data. However, 

the ability of transportation agencies to collect traffic data is limited for 

two major reasons. First, the majority of our nation’s highways and 

arterials do not have the data collection infrastructure to be able to 

provide continued and comprehensive data. This lack of coverage can 

leave significant data gaps in a local road network. Second, even when 

state and local governments have built data collection infrastructure, 

providing funding for its maintenance is difficult and, therefore, this 

infrastructure can fall into disrepair and not provide the data. While the 

development of a performance-based management approach should not be 

totally dependent on the readily available data, transportation research 

does state that agencies should try to optimize the use of existing or 

accessible data in their performance management system. 

Several Strategies Relate 

Mainly to State and Local 

Governments 

Although some strategies cut across all levels of government, other 

options are more appropriately considered by state and local

governments, given their current roles and responsibilities. We identified 

four strategies that state and local transportation agencies, with their 

primary responsibility for building, maintaining, and operating the road 

infrastructure, could consider in their efforts to increase the efficient use 

of existing infrastructure. These options are (1) implementing a 

 30Pub. L. No. 109-59, § 3011(a), codified at 49 U.S.C. § 5309(g)(2)(C). 

Page 37 GAO-07-920 Surface Transportation
combination of supply-related and demand-related congestion mitigation 

techniques, (2) applying congestion mitigation techniques on a regional

basis, (3) fully integrating transportation and land-use planning, and (4) 

providing leadership to build support for implementing comprehensive 

congestion mitigation techniques. 

Research on various congestion mitigation techniques indicates that 

efficient use of the existing road infrastructure is best accomplished 

through an approach that uses a combination of supply-related and 

demand-related techniques. Supply-related congestion mitigation 

techniques include enhancing the capacity and operation of the road 

supply by, for example, using intelligent traffic system and work zone 

management techniques. Demand-related congestion mitigation 

techniques, such as road pricing and a vanpool program, could improve 

the flow and performance of roads by reducing the number of drivers 

using existing roads during peak demand times. Although these congestion 

mitigation techniques can provide benefits when implemented 

individually, using them in a comprehensive manner will provide the 

greatest benefits, according to research. For example, implementing 

supply-related features of intelligent traffic systems can enhance the 

effectiveness of demand-related techniques like commuting on a flexible

schedule by providing real-time traffic information to drivers so that they 

can adjust their departure times to avoid heavy congestion. 

Implement a Combination of 

Supply-Related and DemandRelated Techniques 

To demonstrate the benefits of using a comprehensive approach for 

reducing congestion, DOT has initiated the Urban Partnership Agreement. 

This program will provide financial resources, including some 

combination of grants, loans, and borrowing authority, to transportation 

agencies that implement congestion reduction initiatives that combine 

tolling, transit, telecommuting, and technology as part of a systemwide, 

comprehensive strategy. In addition to the financial assistance, DOT will 

also provide regulatory flexibility and dedicate expertise and personnel to

help transportation agencies implement congestion mitigation techniques. 

DOT announced the selection of nine cities as preliminary partners and is 

planning to announce the selection of between one-five final partners by 

August 8, 2007. 

Since road networks often cross multiple jurisdictions, state and local 

governments need to apply congestion mitigation techniques on a regional 

basis, according to transportation research. By working together, 

jurisdictions can ensure that their efforts to manage congestion include a 

combination of supply-related and demand-related congestion mitigation 

techniques. For example, traffic signal timing is one technique that can 

Apply Congestion Mitigation 

Techniques on a Regional Basis 

Page 38 GAO-07-920 Surface Transportation
provide significant benefits to drivers by providing for the smooth flow of 

traffic along streets and highways. To fully enhance mobility, however, 

jurisdictions need to coordinate the timing along an entire corridor. A 2005 

report by the National Transportation Operations Coalition found that a 

majority—56 percent—of jurisdictions did not report strong efforts in 

coordinating traffic signal timing across jurisdictions.31

Because of the importance of implementing these techniques on a regional 

basis, especially when there are major road corridors involved, a growing 

number of transportation agencies have implemented corridor 

management plans. Corridor management plans can take many forms and 

can be implemented in a number of ways. A recent Transportation 

Research Board study32 reported that transportation agencies have used a 

variety of different instruments to implement these corridor management 

plans, such as memorandums of understandings and intergovernmental 

agreements. For example, the Iowa Department of Transportation entered 

into agreement with three local jurisdictions to implement an access 

management plan, which established access management standards on 

U.S. Highway 6, which runs east to west through Des Moines. This type of 

coordination has also been supported by DOT, through its Integrated 

Corridor Management Initiative. This initiative will provide federal funding

to an agency or organization that demonstrates support of the overall 

concept of corridor management, which could consist of multiple 

jurisdictions. 

Many transportation officials we spoke with stated that transportation 

planning by state and local government must be more fully integrated with

land-use planning, such as zoning policies or growth management policies. 

There is a high level of interconnection between land use and

transportation. For example, the traffic generated from a new major 

shopping center may overwhelm existing transportation infrastructure. 

However, in most areas, land use and transportation decisions are made 

by separate agencies or jurisdictions, with each having significant impact 

on the other’s investment decisions. In cases where there is insufficient 

Integrate Transportation 

Planning More Fully with LandUse Planning 

 31National Transportation Operations Coalition, “National Traffic Signal Report Card: 

Technical Report,” 2005. A total of 378 respondents fully completed the self-assessment. 

The number of signals represented by responding agencies corresponds to about one-third

of all signals in the United States. 

32National Cooperative Highway Research Program, Synthesis 377: Cooperative

Agreements for Corridor Management (Washington, D.C.: 2004). 

Page 39 GAO-07-920 Surface Transportation
coordination between land use and transportation planners, transportation 

agencies may be required to make unanticipated expenditures for 

transportation infrastructure. 

During a Transportation Research Board-sponsored peer exchange on

linking transportation and land use, transportation officials identified a 

number of efforts that are currently being used to better integrate 

transportation and land-use decisions. State transportation officials 

indicated that they have identified several new areas of activity that 

incorporate the concepts of smart growth and transportation planning.33

For example, the Pennsylvania Department of Transportation’s 

Transportation Project and Land Use Coordination Initiative provides 

federal transportation planning funds to local communities for studies and 

coordinated activities linking land-use planning and transportation. 

Our past work34 has found that strong leadership is needed to help build 

support for implementing congestion mitigation techniques on a 

comprehensive basis. There are some techniques, such as the use of 

congestion pricing, which must sometimes overcome political and public 

opposition. Strong leadership can communicate the essential ideas and 

values of a project and, therefore, highlight the benefits that these 

techniques can provide for drivers. For example, in Minnesota, a task 

force of state and local officials, citizens, and business leaders was 

convened in 2001 to explore a range of road pricing options, including the

conversion of HOV lanes to HOT lanes, and make recommendations to 

elected officials. Since tolling had been fairly controversial in the past, the 

task force was seen as a way to provide a more credible and independent

review. Ultimately, with the task force’s and Governor’s support, 

legislation passed that converted HOV to HOT lanes on a major highway. 

Figure 9 provides a brief description of Minnesota’s experience with HOT 

lanes. 

Building Support for 

Congestion Mitigation 

Techniques 

 33The Urban Land Institute defines smart growth as development that is environmentally 

sensitive, economically viable, community-oriented, and sustainable. 

34See GAO, Highway Finance: States’ Expanding Use of Tolling Illustrates Diverse 

Challenges and Strategies, GAO-06-554 (Washington, D.C.: June 28, 2006). 

Page 40 GAO-07-920 Surface Transportation
Figure 9: Minnesota’s “MnPass” Program

Minnesota opened the MnPass Express Lanes in May 2005. The MnPass provides 

single-occupancy drivers the opportunity to pay a toll to use the HOV lanes on 

Interstate 394, which carries traffic to and from downtown Minneapolis and western 

suburbs. The results of the HOT lanes have been significant. A recent survey 

concluded that support for allowing single passenger vehicles to use the HOV lane for 

a fee remained high, with 65 percent of respondents indicating this was a “good idea,” 

1 year after the HOT lane was implemented. In addition, this survey showed that 93 

percent of users were satisfied with the electronic tolling used by MnPass, 88 percent 

were satisfied with the traffic speed in the HOT lanes, and 72 percent were satisfied 

with the safety of merging between the HOT lanes and general purpose lanes. The 

results are based on a survey of 1,228 residents aged 18 years and older living within

the study area in Minnesota. 

Source: NuStats, MnPass Evaluation Attitudinal Panel Survey Wave 3 (Austin, TX.: August 2006). 

Several Strategies Relate 

Mainly to the Federal 

Government to Consider 

The federal government provides funding to state and local governments 

for road and transit infrastructure, establishes legislation and regulations 

that influence the performance and safety of the system, and administers 

transportation programs that cover a range of areas. Given these roles and 

responsibilities, there are several strategies that the federal government 

could consider to help promote the efficient use of infrastructure, 

including (1) linking funding more directly to performance, (2) increasing 

the flexibility provided to state and local government to promote innovate 

solutions, and (3) focusing on projects (or transportation corridors) of 

national interest. 

The federal government could link funding to state and local efforts to 

improve the efficiency and performance of the existing road 

infrastructure. We have previously reported that the federal-aid highway 

funding is currently not linked to performance.35 As a result, the federal 

government misses an opportunity to use financial incentives to improve 

performance and to hold agencies accountable for results. The federal

government could use incentives that link funding to particular outcomes, 

such as implementing congestion mitigation techniques to encourage state 

and local governments to use existing infrastructure more efficiently. 

Incentives could also be used to increase state, regional, and local 

agencies’ utilization of analytical information and tools to ensure that 

decision makers are making investment decisions that fully examine all 

alternatives, including congestion mitigation techniques. 

Link Federal-Aid Highway 

Funding to Performance 

 35See GAO-05-172. 

Page 41 GAO-07-920 Surface Transportation
The federal government could provide additional flexibility to state and 

local governments for implementing innovative solutions to reduce 

congestion and enhance mobility, according to transportation experts. 

This flexibility could take many forms. First, the federal government could 

build on trends giving states greater flexibilities and discretion with their 

federal-aid highway program funds.36 Increasing flexibility and discretion 

would recognize the changing nature of FHWA’s role and the federal-aid 

highway program, which has been functioning, to some extent, as a 

revenue sharing, general purpose grant program. Devolving funding 

responsibilities to the states in a manner consistent with that function 

would build on the flexibilities already present and would not require 

abandoning the program’s regulatory component. For example, states and

localities could use federal-aid highway funding to implement travel 

demand management techniques such as increasing the number of 

vanpools. 

Increase Flexibility to State and 

Local Decision Makers 

The federal government could also continue to liberalize some of the longstanding federal restrictions on states and local governments’ use of 

congestion mitigation techniques, such as road pricing techniques. By 

removing these restrictions, the federal government would allow state and 

local governments to expand the use of certain user-pay options. For 

example, because states have recognized that many HOV lanes have been 

underused and, therefore, have excess capacity, HOT lanes are becoming 

more widely accepted by state and local governments as a way to 

maximize existing road capacity by managing demand and offering drivers 

additional choices. SAFETEA-LU enhanced and clarified provisions on the 

states’ ability to build or convert existing HOV lanes on interstate 

highways into HOT lanes, as long as states monitor and assess the 

operation of the lanes to ensure the lanes do not become degraded.37

However, there are still restrictions on the states’ ability to implement 

road pricing techniques on general purpose lanes. For example, SAFETEA-

 36States have broad flexibility to transfer funds between the various federal-aid grant 

programs. For example, states may transfer up to 50 percent of their Interstate 

Maintenance and National Highway System Program funds to other programs, including

the Surface Transportation Program, which has broad eligibility rules. In addition, 

authorizing statutes, most recently amended by SAFETEA-LU, provided the states broad 

authority to transfer federal-aid Highway funds to transit projects and vice versa. 

37The Federal Transit Administration (FTA) issued guidance on the terms and conditions 

on which FTA will classify HOV lanes that are converted to HOT lanes as “fixed guideway

miles” for purposes of the transit funding formulas administered by FTA. 

Page 42 GAO-07-920 Surface Transportation
LU includes an explicit restriction on the use of road pricing techniques on 

Interstate 4 in Orange County, Florida. 

The federal government could refocus its role and become more active in

the management of the surface transportation infrastructure on projects 

that are within the national interest. In our prior work,38 we have stated 

that government investment in transportation projects, such as freight 

improvement projects or intermodal projects at airports, may be 

warranted if there is the potential of producing benefits to the public and if 

these projects are unattractive to the private sector. Public benefits could 

include reducing the external costs of transportation, such as reducing 

fuel emissions and roadway congestion. Considering whether the project

has the potential to reduce the external cost of transportation provides an

indication of a project’s potential for yielding a good return. The federal 

government could take a more active role, beyond funding and oversight, 

if certain projects could provide public benefits. For example, in our 

freight work, we highlighted that improving freight mobility through the 

implementation of a short sea shipping service may have the effect of 

shifting some freight from truck to water and, as a result, reduce external 

costs such as pollution and congestion. Federal options could range from

providing public subsidies to the private sector to taking on a more active 

planning role, such as during the development of the interstate highway 

system. However, such options would involve a fundamental shift in 

federal transportation policy, and officials would have to implement this 

option carefully to ensure that this support would result in real economic 

benefits, from a national perspective, and not represent a transfer of 

economic activity from one area to another. 

Placing Additional Focus on 

Projects That Provide National 

Public Benefits 

The demand on our nation’s road infrastructure is expected to continue 

increasing for the foreseeable future. This continued demand comes at a 

time when many of the nation’s major roadways are at capacity during 

peak hours—creating increasing levels of congestion throughout the 

nation. Given today’s fiscal, environmental, and land-use concerns, the 

days when our nation could build our way out of congestion have passed. 

Concluding 

Observations 

 38GAO, Intermodal Transportation: Potential Strategies Would Redefine Federal Role in

Developing Airport Intermodal Capabilities, GAO-05-727 (Washington, D.C.: July 26, 

2005); and GAO, Freight Transportation: Short Sea Shipping Option Shows Importance 

of Systematic Approach to Public Investment Decisions, GAO-05-768 (Washington, D.C.: 

July 29, 2005). 

Page 43 GAO-07-920 Surface Transportation
In general, however, transportation policy is still focused on building or 

maintaining road capacity—not efficiently operating and managing the 

existing infrastructure. Many transportation experts emphasize that 

transportation policy should be refocused to allow decision-makers to use 

all the tools at their disposal to more efficiently operate and manage their 

infrastructure—including nonbuild congestion mitigation techniques, such

as congestion pricing. Congress and DOT have recognized the importance 

and benefits of efficiently managing and operating the existing

infrastructure. Some state and local governments have also adopted 

congestion mitigation techniques, such as HOT lanes. However, to date, 

such efforts at the state and local level have been confined to a limited 

number of locations and have not typically been a part of a more 

comprehensive strategy to operate and manage the existing infrastructure 

more efficiently. Until congestion mitigation techniques are used in a more 

comprehensive manner, the full potential of these techniques will not be 

realized. DOT’s emphasis on increasing the efficient use of existing 

infrastructure in its national strategy to reduce congestion is an important 

step forward. As DOT moves forward with the implementation of this 

strategy, it will likely have the opportunity to explore strategies to provide 

incentives to state and local governments to consider and implement 

congestion mitigation techniques in a more comprehensive manner, 

including the strategies we identified. 

We provided copies of this report to DOT for its review and comment. 

DOT officials provided technical clarifications, which we incorporated as 

appropriate.

Agency Comments 

and Our Evaluation 

We will send copies of this report to congressional committees with 

responsibilities for surface transportation programs, DOT officials, 

including the Secretary of Transportation, and the administrator of FHWA. 

We will make copies available to others on request. In addition, the report

will be available at no charge on the GAO web site at http://www.gao.gov. 

Page 44 GAO-07-920 Surface Transportation
If you have any questions about this report, please contact me at 

heckerj@gao.gov or by telephone at (202) 512-2834. Contact points for our 

Offices of Congressional Relations and Public Affairs may be found on the 

last page of this report. GAO staff who made key contributions to this 

report are listed in appendix III. 

Sincerely yours, 

JayEtta Z. Hecker 

Director, Physical Infrastructure Issues 

Page 45 GAO-07-920 Surface Transportation
Appendix I: Objectives, Scope, and Appendix I: Objectives, Scope, and Methodology 

Methodology 

The objectives of this report were to (1) identify the factors that inhibit the 

efficient use of the existing infrastructure of roads and highways, (2) 

identify what techniques have been developed for making the current 

infrastructure more efficient and what is known about the results, (3) how 

local decision makers have implemented these techniques, and (4) what 

strategies exist for increasing the efficient use of existing infrastructure? 

To identify the factors that inhibit the efficient use of the existing 

infrastructure of roads and highways, we reviewed reports and studies 

issued by federal, state, and local agencies, transportation research 

organizations, and academia, as well as our past work in surface 

transportation. A GAO economist reviewed these reports and studies, 

which were identified by searching economics and transportation 

literature, and found their methodology and economic reasoning to be 

sound and sufficiently reliable for our purposes. 

To identify the techniques that have been developed to make more 

efficient use of the transportation infrastructure and what is known about 

the results of these techniques, we interviewed Department of 

Transportation’s Federal Highway Administration officials and state and 

local transportation officials from our site visit locations, as well as 

representatives from various associations with experience implementing 

and/or analyzing the results of such techniques. We also reviewed 

transportation research by transportation organizations and studies and 

evaluations of individual projects conducted by federal, state, and local 

transportation agencies.

To determine how local decision makers have implemented these 

techniques and what is known about the extent to which these approaches 

are making the current infrastructure more efficient, we conducted site 

visits or interviews of federal, state, and local transportation officials 

about urban areas in five states that have experience with implementing 

various congestion management techniques—Denver, Colo.; Northern 

Virginia, Va.;1

 Orlando, Fla.; San Diego, San Francisco-Oakland, and San 

Jose, Calif.; and Seattle, Wash. We selected this nongeneralizable sample 

of states based on geographical diversity and after reviewing the Texas 

Transportation Institute’s 2005 “Urban Mobility Report” to identify states 

with congested urban areas; and by interviewing agency officials, 

association representatives, and reviewing studies and reports to 

 1

These interviews were conducted by telephone. 

Page 46 GAO-07-920 Surface Transportation
Appendix I: Objectives, Scope, and 

Methodology 

determine states that had a higher level of experience planning and 

implementing various congestion mitigation techniques. We also 

interviewed officials in Aurora and Boulder, Colo.; Altamonte Springs, Fla.; 

Hampton Roads, Va.;2

 and Bellevue and Issaquah, Wash. to gain some 

insight into the implementation of congestion mitigation techniques in 

smaller jurisdictions. We also reviewed how other states have

implemented congestion mitigation techniques, and we note these in this

report. 

To identify the strategies that might be employed for addressing 

anticipated strains on infrastructure over the long term, we reviewed 

public and private sector research, studies, and proposals on the 

development of new long term strategies and built on the perspectives 

gained from our past work in transportation infrastructure and congestion. 

This was supplemented with interviews of officials in the Department of 

Transportation (DOT) and the Federal Highway Administration (FHWA) 

and stakeholders including the American Association of State Highway 

and Transportation Officials, Institute of Transportation Engineers, ITS 

America, and Environmental Defense. We conducted our work from 

September 2006 through July 2007 in accordance with generally accepted 

government auditing standards. 

 2

These interviews were conducted by telephone. 

Page 47 GAO-07-920 Surface Transportation
Appendix II: Congestion Mitigation 

Techniques and Benefits

Transportation agencies nationwide use a wide array of congestion 

mitigation techniques to manage congestion and maximize the existing 

transportation infrastructure. These techniques have the potential to 

provide benefits that improve efficiency by improving traffic flow, altering 

existing commuter patterns that cause congestion, and increasing the use 

of alternative transportation modes such as public transit and car pools. In

general, these congestion mitigation techniques can be placed into two 

basic categories, techniques that are aimed at enhancing existing capacity, 

and techniques that influence driver behavior. 

Techniques that enhance capacity: These are techniques that are designed

to increase the existing systems’ capacity to improve travel flow. For 

example, incident management programs are designed to more rapidly 

deploy response vehicles that remove accident vehicles and debris and 

more quickly restore traffic flow after accidents. Table 2 provides a brief 

description of selected congestion mitigation techniques designed to 

enhance capacity, and the potential benefit of each technique.

Table 2: Selected Congestion Mitigation Techniques That Enhance Capacity

Technique Benefit

Traffic signal timing—coordinating the timing of a series of traffic 

signals along an arterial to reduce stops and move vehicles at a 

uniform speed.

Optimizing traffic signal timing increases vehicle speeds and

traffic volumes and reduces accidents on major arterials. 

Incident management program—is a planned and coordinated 

program to detect, respond to, and remove traffic incidents. 

Removing vehicles from the accident scene helps to reduce 

incident-related congestion and restore traffic capacity as safely 

and quickly as possible. 

Work zone management—using techniques such as warning 

signs, reversible lanes, and public awareness campaigns during 

road construction. 

Use of work zone management techniques during road 

construction helps to minimize construction delays and related 

congestion. 

Bus, vanpool, and car pool lanes—setting aside dedicated highoccupancy vehicle (HOV) lanes for buses, vanpools, and car 

pools on freeways. 

Dedicated lanes for buses, vanpools, and car pools provide a 

faster, more predictable travel time. By increasing the average 

number of people per vehicle, HOV lanes increase the overall 

capacity of the roadway. 

Access management—a set of techniques that state and local 

governments can use to control vehicle access to highways, major 

arterials, and other roadways, for example, limiting access to 

freeways, increasing the spacing between signals and 

interchanges, and use of frontage and service roads. 

Techniques such as controlling signal spacing improves traffic 

flow and reduces congestion and accidents. 

Appendix II: Congestion Mitigation 

Techniques and Benefits 

Page 48 GAO-07-920 Surface Transportation
Appendix II: Congestion Mitigation 

Techniques and Benefits

Technique Benefit

Integrated corridor management—the operational coordination 

of specific transportation networks comprising a corridor, and the 

coordination of agencies responsible for corridor mobility. 

Managing a corridor in an integrated manner is aimed at reducing 

travel times, improving travel predictability, and increasing transit 

ridership in the corridor. 

Asset management—a systematic process of maintaining, 

upgrading, and operating transportation assets cost effectively by 

applying engineering principles, sound business and economic 

practices, and a framework for planning and decision making. 

An asset management program that includes regular maintenance 

and rehabilitation of roads can result in improved speed and 

reliability of passenger and freight travel. 

Source: GAO.

Techniques that influence driver behavior: These are techniques that are 

designed to reduce vehicle demand on the existing system by reducing the 

frequency of travel and travel during peak periods, altering the routes 

traveled, and providing incentives to use alternate transportation modes. 

For example, high-occupancy toll (HOT) lanes could charge singleoccupancy vehicles a higher price during peak congestion times, and this 

provides incentives for drivers to travel at less congested times. Other 

policies, such as employer transit subsidies and flexible work schedule 

programs, can also shift drivers’ use of the road network and thus reduce 

demand on the existing transportation infrastructure. Table 3 provides a 

brief description of selected congestion mitigation techniques designed to 

influence driver behavior and the potential benefit of each technique. 

Table 3: Select Congestion Mitigation Techniques That Influence Driver Behavior

Technique Benefit

High-occupancy toll (HOT) lanes—a priced lane that offers drivers 

of vehicles that do not meet the occupancy requirements the option 

of paying a toll to use lanes that are otherwise restricted to highoccupancy vehicles. 

HOT lanes can channel traffic into underutilized lanes and 

decrease congestion on regular lanes thus increasing the 

overall throughput of a corridor. HOT lanes can also shift 

demand to less congested times by charging a lower toll just

before and after peak period. 

Cordon-based pricing—a form of congestion pricing where drivers 

are charged a fee to enter a congested area such as a city center 

during peak periods. 

Charging a fee to enter a central business district during peak 

periods encourages travelers to shift their behavior by either 

traveling at another time or by using alternative transportation 

modes such as buses and trains. 

Employer transit and vanpool subsidies—employers pay for 

employee monthly transit pass expenses. 

Designed to provide an incentive for employees to use transit

services resulting in reduced traffic demand on the road

network. 

Real Time Traveler Information Web sites—Web sites that 

provide up-to-the-minute information on traffic conditions such as 

speeds, levels of congestion, and camera views of roads and 

incidents before the commuter starts out. 

Providing information on congestion, commute times, and 

alternate routes allows a traveler to change time of departure, 

route, or mode of transport to avoid congestion and arrive at a 

destination in timely manner. 

Page 49 GAO-07-920 Surface Transportation
Appendix II: Congestion Mitigation 

Techniques and Benefits

Technique Benefit

Worksite flextime—allows employees to set their own arrival and 

departure time to/from work—within established time boundaries 

agreed to by their employer. 

Encourages employees to avoid the most congested travel 

times, reducing the demand on roadway and/or transit systems 

during peak-demand periods. 

Telework policies—allow employees to work at home during a 

portion of the workweek. 

Working at home results in fewer trips to work and reduced 

demand on roads and transit systems. 

Land use and development policies and incentives—policies 

and incentives that encourage future growth near existing road and 

transit services.

Locating new residential development near existing transit 

facilities will make more efficient use of existing transit services 

with the potential to reduce demand on existing roads. 

Parking management—managing the supply and price of parking

such as limiting the amount of single-occupancy parking spaces, 

charging higher parking fees, or providing preferential parking for 

car pools and vanpools. 

Managing parking supply and price provides a disincentive for 

driving alone and an incentive for using alternate modes of 

travel. 

Source: GAO.

Page 50 GAO-07-920 Surface Transportation
Appendix III: GAO

A

 Contact and Staff 

cknowledgments 

Page 51 GAO-07-920

Appendix III: GAO Contact and Staff 

Acknowledgments 

JayEtta Z. Hecker, (202) 512-2834, heckerj@gao.gov

In addition to the individual named above, Nikki Clowers, Assistant 

Director; Ashley Alley; Jay Cherlow; Anne Dilger; Brad Dubbs; Terence 

Lam; Maureen Luna-Long; Sara Ann Moessbauer; and Tim Schindler made 

key contributions to this report. 

GAO Contact 

Staff 

Acknowledgments 

(544129) Surface Transportation
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