HIGHWAY TRUST 

FUND

Pilot Program Could 

Help Determine the 

Viability of Mileage 

Fees for Certain 

Vehicles

Report to the Subcommittee on 

Transportation, Housing, and Urban 

Development, and Related Agencies, 

Committee on Appropriations, House of 

Representatives

December 2012

GAO-13-77

United States Government Accountability Office

GAO
United States Government Accountability Office

Highlights of GAO-13-77, a report to 

Subcommittee on Transportation, Housing and 

Urban Development, and Related Agencies, 

Committee on Appropriations, House of 

Representatives

December 2012

HIGHWAY TRUST FUND

Pilot Program Could Help Determine Viability of 

Mileage Fees for Certain Vehicles 

Why GAO Did This Study

Federal funding to build and maintain 

the nation’s highways and bridges

comes primarily from highway users 

through federal fuel taxes. These 

revenues have eroded due to 

improvements in vehicle fuel efficiency

and other factors contributing to 

shortfalls in the Highway Trust Fund. 

Experts have proposed alternative 

means of raising revenues by charging 

drivers fees based on their miles 

traveled. Several states have tested 

systems that gather vehicle mileage 

and location data, which has raised 

privacy concerns. GAO examined (1)

the benefits and challenges of mileage 

fee initiatives in the United States and 

other selected nations, (2) mileage fee 

rates necessary to replace and 

supplement current Highway Trust 

Fund revenues and the effect these 

fees would have on users’ costs, and 

(3) state DOTs’ views on future 

revenue demands and mileage fees.

GAO reviewed five domestic pilot 

projects and programs in Germany, 

New Zealand, and the Netherlands; 

modeled mileage fees for passenger 

vehicles and commercial trucks; and 

surveyed 51 state DOTs.

What GAO Recommends

Should Congress further explore 

mileage fees, it should consider 

establishing a pilot program to test the 

viability of such fees for commercial 

trucks and electric vehicles. FHWA 

should update its estimates of road 

damages imposed by all vehicle types

compared with the tax revenues 

generated by each. The Department of 

Transportation took no position on 

GAO’s recommendation but provided 

technical comments which GAO

incorporated as appropriate. 

What GAO Found

Mileage-based user fee initiatives in the United States and abroad show that 

such fees can lead to more equitable and efficient use of roadways by charging 

drivers based on their actual road use and by providing pricing incentives to 

reduce road use. Mileage fees for passenger vehicles, however, continue to face 

significant public concerns related to privacy as well as cost challenges. Privacy 

concerns are particularly acute when Global Positioning System (GPS) units are 

used to track the location of passenger vehicles. Reliable cost estimates for 

mileage fee systems are not available, but implementing a system to collect fees 

from 230 million U.S. passenger vehicles is likely to greatly exceed the costs of 

collecting fuel taxes. Commercial truck user fee systems in Germany and New 

Zealand have achieved substantial revenues and benefits such as reduced road 

damage and emissions with fewer privacy concerns, but ensuring compliance in 

a cost effective manner presents trade-offs. Few commercial truck mileage fee

pilots have been conducted in the United States, but efforts in two states suggest 

such fees pose fewer privacy and cost challenges than passenger vehicle fees. 

Mileage fee rates could be set to replace or supplement current Highway Trust 

Fund revenues. GAO calculated average mileage fee rates for passenger 

vehicles and commercial trucks needed to meet three federal revenue targets 

ranging from $34 billion (replace current federal fuel tax revenues) to $78 billion

(increase spending to maintain existing system conditions and performance). To 

meet these targets, drivers of passenger vehicles with average fuel efficiency 

would pay $108 to $248 per year in mileage fees compared to the $96 these 

drivers currently pay in federal gasoline tax. These fees would affect users’ costs 

differently based on each vehicle’s fuel efficiency, because drivers of less 

efficient vehicles now pay more in fuel taxes than drivers of vehicles with greater 

fuel efficiency. However, like federal fuel taxes, mileage fees would comprise a 

small portion of users’ overall fuel costs and thus only marginally increase users’ 

overall transportation costs. A mileage fee for commercial trucks could also 

increase users’ costs, particularly for larger trucks that log more miles. In 2000, 

the Federal Highway Administration (FHWA) estimated that heavy commercial 

trucks generally pay less in federal taxes than the road damage costs they 

impose. Adjusting mileage fee rates to account for vehicle road damage costs 

would increase rates for commercial truck users. However, FHWA’s estimates 

may not reflect current conditions. Setting rates to cover these costs would 

require updated estimates of vehicles’ responsibility for road damage.

State departments of transportation (DOT) recognize the need for an alternative 

funding mechanism to meet future revenue demands, and many would support 

federal actions to evaluate mileage fees. Few states reported that they are likely 

to introduce such fees in the next 10 years, but more than half would support

federally-led field tests of mileage fees for commercial trucks and electric 

vehicles. Although few electric vehicles are on the roads today, their numbers are 

expected to increase, and they do not contribute to the Highway Trust Fund.

Without a federal pilot program to evaluate (1) options to more accurately charge

commercial trucks and electric vehicles for their road use and (2) the costs and 

benefits of such systems, Congress lacks critical information to assess whether 

mileage fees for these vehicles could be a viable and cost-effective tool to help 

address the nation’s surface transportation funding challenges. 

View GAO-13-77. For more information, 

contact Susan Fleming at (202) 512-2834 or 

flemings@gao.gov.
Page i GAO-13-77 Highway Trust Fund

Letter 1 

Background 5

Various Initiatives Demonstrate Mileage Fee Benefits, but Privacy 

Concerns and Cost Challenges Hinder Passenger Vehicle 

Systems 14

Mileage Fees Could Generate Highway Trust Fund Revenues and 

Would Affect Users Differently 32

States Recognize That Alternative Transportation Revenues Are 

Needed, and Many Would Support Federal Actions to Evaluate 

Mileage Fee Systems 45

Conclusions 48

Matters for Congressional Consideration 50

Recommendation for Executive Action 50

Agency Comments 51

Appendix I Objectives, Scope, and Methodology 52

Appendix II U.S.-based Pilot Projects on Mileage-based User Fees 61

Appendix III User Fee Design Criteria 63

Appendix IV The Fair Information Practices 64

Appendix V Mileage-based User Fee Simulation Model 65

Appendix VI Results of GAO Survey of State Departments of Transportation 

about Mileage Fees 69

Appendix VII GAO Contact and Staff Acknowledgments 75

Contents 
Page ii GAO-13-77 Highway Trust Fund

Tables

Table 1: Benefits and Challenges of Mileage Fee Systems 18

Table 2: Illustrative Federal Mileage Fee Rates for Three Revenue 

Scenarios 35

Table 3: Values of Key Parameters Used in Simulation 57

Table 4: Summary of Mileage-based User Fee Pilot Projects in the 

United States, as of June 2012 61

Table 5: GAO Criteria for User Fee Design 63

Table 6: The Fair Information Practices 64

Table 7: Description of Key Parameters and Variables Used in 

Simulation Analysis 65

Figures

Figure 1: Sources of Revenue for the Highway Trust Fund, Fiscal 

Year 2010 6

Figure 2: Federal Gasoline Tax as a Percentage of the Average 

Retail Price per Gallon of Gasoline, 1993 to 2011 7

Figure 3: Projected Highway Trust Fund Balance, 2012 to 2022 8

Figure 4: Average Annual Federal Fuel Taxes Paid by Passenger 

Vehicles 9

Figure 5: Annual Federal Fuel Taxes Paid by Commercial Trucks in 

2010 10

Figure 6: Depiction of Three Passenger Vehicle Mileage Fee 

Approaches 15

Figure 7: German HGV Enforcement Gantry and Mobile 

Enforcement Vehicle 26

Figure 8: Average Passenger Vehicle Users’ Annual Federal Fuel 

Taxes Paid under Current System Compared with 

Mileage Fee Scenarios 37

Figure 9: Average Passenger Vehicle Users’ Monthly Fuel and Tax 

Costs under Current System and Mileage Fee Scenarios 38

Figure 10: Average Commercial Truck Users’ Annual Federal Fuel 

Taxes Paid under Current System Compared with 

Mileage Fee Scenarios 40

Figure 11: Average Commercial Truck Users’ Monthly Fuel and 

Fuel Tax Costs under Current System and Mileage Fee 

Scenarios 41

Figure 12: Illustrative Federal Mileage Fee Rates for Three Revenue 

Scenarios, Adjusted for Cost Responsibility 44
Page iii GAO-13-77 Highway Trust Fund

Figure 13: Number of State DOTs Reporting High Priority on 

Various Transportation Funding Mechanisms, 2012 48

Figure 14: Overview of the Algorithm of Computing Mileage Fees 

to Generate Predetermined Revenue 67

Abbreviations

AASHTO American Association of State Highway 

 Transportation Officials 

CAFE Corporate Average Fuel Economy 

CBO Congressional Budget Office

DOT department of transportation

E-RUC Electronic Road User Charge

FHWA Federal Highway Administration

GPS Global Positioning System 

HGV Heavy Goods Vehicle

IFTA International Fuel Tax Agreement

IRP International Registration Plan 

MAP-21 Moving Ahead for Progress in the 21st Century Act

MPG miles per gallon

NCHRP National Cooperative Highway Research Program

NSTIFC National Surface Transportation Infrastructure 

 Financing Commission

PSRC Puget Sound Regional Council

RUC Road User Charge

SAFETEA-LU Safe, Accountable, Flexible, Efficient 

 Transportation Equity Act: A Legacy for Users

SUV sport utility vehicle

TRUE Truck Road Use Electronics 

VMT vehicle miles traveled

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Page 1 GAO-13-77 Highway Trust Fund

United States Government Accountability Office

Washington, DC 20548

December 13, 2012

The Honorable Tom Latham

Chairman

The Honorable John W. Olver

Ranking Member

Subcommittee on Transportation, Housing and

Urban Development, and Related Agencies

Committee on Appropriations

House of Representatives

The nation’s surface transportation system is critical to the economy and 

affects the daily lives of most Americans. However, the system is under 

growing strain, and the costs of repairs and upgrades to meet current and 

future demands are estimated in the hundreds of billions of dollars. For 

more than 50 years, federal funding to build and maintain the nation’s 

vast network of highways and bridges has been collected primarily from 

highway users through federal fuel taxes. This system is based on the 

“user pays” principle in which the costs of government programs or 

services, such as the construction and maintenance of roadways, are 

paid by the individuals and firms that use and benefit from the service 

through taxes or fees. For many years, user fees in the form of federal 

fuel taxes and taxes on commercial trucks provided sufficient revenues to 

the Highway Trust Fund, the primary source of federal funding for 

highway and transit programs.1

To maintain current spending levels and cover revenue shortfalls, 

Congress transferred more than $34 billion in general revenues to the 

Highway Trust Fund from fiscal year 2008 to 2010; in 2012, Congress 

appropriated an additional $18.8 billion in general revenues for fiscal 

However, revenues into the fund have 

eroded over time, in part because federal fuel tax rates have not 

increased since 1993 and in part because of improvements in vehicle fuel 

efficiency. This trend will continue in the years ahead as more alternative 

fuel vehicles take to the roads.

 

1

The Highway Trust Fund is an account established by law to hold federal highway user 

tax receipts (e.g., receipts for federal excise taxes on fuel and other taxes on commercial 

trucks) that are dedicated for highway and transit related purposes. It is composed of two 

accounts: the highway account and the mass transit account.

 
 

Page 2 GAO-13-77 Highway Trust Fund

years 2013 and 2014.2 This approach has effectively broken the link 

between taxes paid and benefits received by users and may not be

sustainable given competing demands and the federal government’s 

growing fiscal challenge.3 Although the President signed a 2-year surface 

transportation authorization in July 2012,4 the Highway Trust Fund faces 

significant shortfalls in the years ahead, beginning in fiscal year 2015, to 

support current spending levels. Congress and the Administration have 

yet to develop a long-term plan for funding surface transportation;

ultimately, increased surface transportation revenues, reduced 

transportation spending levels, or both will be needed to bring revenues 

and spending into balance. For this and other reasons, funding surface 

transportation remains on GAO’s High-Risk List.5

To address this growing funding problem, transportation experts and 

economists have advocated developing an alternative revenuegenerating system that preserves the user-pay principle by charging 

vehicle owners based on the number of miles they drive—that is, by their 

vehicle miles traveled. Such fees, commonly known as VMT fees or 

mileage-based user fees, are referred to as “mileage fees” in this report. 

Advocates of mileage fees argue that in addition to raising revenues, 

such fees may offer other benefits that could lead to more efficient use of 

the nation’s highways and result in reduced congestion for drivers. For 

example, mileage fees and other forms of road pricing such as tolling 

send clear price signals to road users, and provide incentives to drivers to 

consider alternatives such as public transit or carpooling which can 

reduce congestion, vehicle emissions, and overall spending on fossil 

 

2

In fiscal year 2008, about $8 billion was transferred from the general fund to the highway 

account (Pub. L. No. 110-318, § 1(a)(4), 122 Stat. 3532 (Sept. 15, 2008)); in fiscal year 

2009 the transfer was $7 billion (Pub. L. No. 111-46, §1, 123 Stat 1970 (Aug. 7, 2009)); 

and $14.7 billion was transferred to extend highway programs to December 31, 2010, and 

$4.8 billion was transferred to the mass transit account (Hiring Incentives to Restore 

Employment Act, Pub. L. No. 111-147, § 442, 124 Stat. 71, 94 (Mar. 18, 2010)). For fiscal 

year 2013, $6.2 billion is appropriated to the highway account; for fiscal year 2014, $10.4 

billion is appropriated to the highway account and $2.2 billion is appropriated to the mass 

transit account (Moving Ahead for Progress in the 21st Century Act (MAP-21), Pub. L. No. 

112-141, § 4025, 126 Stat. 405, 864 (July 6, 2012)). 

3

GAO, Highway Trust Fund: All States Received More Funding Than They Contributed in 

Highway Taxes from 2005 to 2009, GAO-11-918 (Washington, D.C.: Sept. 8, 2011).

4

MAP-21. 

5

GAO, High-Risk Series: An Update, GAO-11-278 (Washington, D.C.: February 2011). 
 

Page 3 GAO-13-77 Highway Trust Fund

fuels. The Congressional Budget Office (CBO) reported that most drivers 

currently pay much less than the full cost of their highway use, and that 

mileage fees could provide a better incentive for efficient highway use 

than fuel taxes do because the majority of highway costs are related to 

miles driven.6 In addition, we have reported that if those who benefit from 

a program do not bear the full social cost of the service, they may seek to 

have the government provide more of the service than is economically 

efficient.7 Furthermore, two national transportation commissions 

established by Congress have reported that reforming highway financing 

with a mileage fee system could provide a more viable, long-term source 

of federal revenues than the current system of fuel and excise taxes.8

In recent years, several states have conducted pilot projects to test 

mileage fee systems and other countries have also evaluated or 

implemented mileage fees for light passenger vehicles or heavy 

commercial trucks. Efforts to evaluate mileage fees in the United States 

have been met with concerns from the general public, including the fear 

that installing Global Positioning System (GPS) technology into private 

vehicles to gather mileage data could also potentially be used to 

compromise drivers’ personal information, such as locations visited.

In light of these concerns, you asked us to review the issues surrounding 

the possible use of a mileage-based user fee system to fund federal 

surface transportation programs. In this report we examine:

1. the benefits achieved and challenges faced in mileage fee initiatives 

in the United States and selected other nations,

2. the user fee rates necessary to replace and supplement current 

revenues to the Highway Trust Fund and the effect these fees would 

have on users’ costs, and

 

6

Congressional Budget Office, Alternative Approaches to Funding Highways, Pub. No. 

4090 (Washington, D.C., March 2011).

7

GAO, Federal User Fees: A Design Guide, GAO-08-386SP (Washington, D.C.: May 29, 

2008).

8

National Surface Transportation Policy and Revenue Study Commission, Transportation 

for Tomorrow (Washington, D.C., December 2007); National Surface Transportation 

Infrastructure Financing Commission, Paying Our Way: A New Framework for 

Transportation Finance (Washington, D.C., February 2009).
 

Page 4 GAO-13-77 Highway Trust Fund

3. the perspectives of state departments of transportation (DOT) on 

addressing future revenue demands using mileage fees.

To examine these issues, we gathered information on the benefits and 

challenges of several mileage fee pilot projects conducted in the United 

States, including efforts in Oregon and Washington, and a national-level 

evaluation conducted in 12 states that was authorized by the Safe, 

Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for 

Users (SAFETEA-LU).9

We conducted this performance audit from December 2011 through 

December 2012 in accordance with generally accepted government 

auditing standards. Those standards require that we plan and perform the 

audit to obtain sufficient, appropriate evidence to provide a reasonable 

basis for our findings and conclusions based on our audit objectives. We 

believe that the evidence obtained provides a reasonable basis for our 

findings and conclusions based on our audit objectives. Our objectives, 

scope, and methodology are discussed in more detail in appendix I.

We also reviewed preliminary results from two 

ongoing pilot projects in Minnesota and Nevada. We interviewed 

transportation officials involved with all of these pilots. To gather 

information on the benefits and challenges of international mileage fee 

initiatives, we selected programs in Germany, New Zealand, and the 

Netherlands based on criteria that included program objectives, 

administration, and technologies used. We reviewed program documents 

and interviewed transportation officials in these countries to gather 

information on Germany’s Heavy Goods Vehicle user fee system, New 

Zealand’s Road User Charge system, and a cancelled user fee program 

in the Netherlands. To determine the mileage fee rates that would be 

necessary to replace and supplement current Highway Trust Fund 

revenues, we selected three revenue targets and simulated the user fee 

rates for passenger vehicles and commercial trucks that would be 

necessary to achieve those targets using fiscal year 2010 data. We also 

simulated the mileage fees that would be required if all vehicles were 

responsible for the road damage they caused according to Federal 

Highway Administration (FHWA) estimates. To obtain states’ views on 

addressing future revenue demands using mileage fees, we surveyed the 

DOTs in all 50 states and the District of Columbia and received a 100 

percent response rate.

 

9

Pub. L. No. 109-59, § 1919 (a), (d), 119 Stat. 1144, 1479-1480 (2005). 
 

Page 5 GAO-13-77 Highway Trust Fund

Since Congress established the Highway Trust Fund in 1956 to fund the 

construction of the Interstate Highway System, the federal government 

has financed transportation projects primarily with revenues collected 

through federal fuel taxes. These taxes were established to make the 

federal-aid highway program self-financing—that is, paid for by the 

highway users who directly benefit from the program.10 From 1956 to 

1993, Congress increased the federal gasoline tax from 3 cents per 

gallon to its current rate of 18.4 cents per gallon. The federal diesel tax 

rate was also last increased in 1993 and is currently set at 24.4 cents per 

gallon. In fiscal year 2010, 92.5 percent of almost $37 billion in user fee 

revenues deposited into the Highway Trust Fund were generated through 

federal fuel taxes.11 The remaining revenues were collected through 

several taxes on heavy commercial trucks.12

 

10Federal fuel taxes are not directly paid by highway users but are reflected in retail fuel 

prices. Oil companies typically pay a per-gallon tax on fuels at the point of distribution, and 

these costs become part of the purchase price paid by highway users.

(See fig. 1.)

11This includes $24.8 billion and $9.1 billion in federal gasoline and diesel taxes, 

respectively, and $2.8 billion in truck taxes. This amount does not include the $19.5 billion 

in general fund revenues deposited into the Highway Trust Fund or the $1.2 billion in 

rescissions and transfers to other funds in 2010. 

12Federal truck taxes include: (1) truck and trailer sales tax of 12 percent of retailer’s sale 

price for tractors and trucks over 33,000 pounds gross vehicle weight and trailers over 

26,000 pounds gross vehicle weight; (2) a heavy-vehicle use tax for trucks weighing 

55,000 pounds or more that ranges from $100 to a maximum of $550 per year based on 

weight; and (3) a tire tax for the purchase of tires, based on tire size and weight, of 9.45 

cents for each 10 pounds of the maximum rated load capacity over 3,500 pounds.

Background 

Financing of U.S. Surface 

Transportation Programs
 

Page 6 GAO-13-77 Highway Trust Fund

Figure 1: Sources of Revenue for the Highway Trust Fund, Fiscal Year 2010

Over the past two decades, revenues from federal gasoline and diesel 

fuel taxes have steadily declined in purchasing power. These rates are 

not set to be adjusted for inflation on an annual basis, meaning that the 

18.4 cents per-gallon tax on gasoline enacted in 1993 is effectively worth 

about 11.5 cents today.13

 

13GAO, Transportation: Key Issues and Management Challenges, 

If federal gasoline taxes had been indexed to 

inflation since they were last increased, they would have risen from 18.4 

cents per gallon in 1993 to approximately 29 cents per gallon in 2011; 

diesel taxes would have risen from 24.4 cents per gallon to 38 cents per 

gallon. In addition, as shown in figure 2, the amount of federal gasoline 

GAO-12-581T

(Washington, D.C.: Mar. 29, 2012). 
 

Page 7 GAO-13-77 Highway Trust Fund

tax relative to the average retail price of gasoline decreased from 17 

percent in 1993 to 5 percent in 2011.14

Figure 2: Federal Gasoline Tax as a Percentage of the Average Retail Price per Gallon of Gasoline, 1993 to 2011

Surface transportation programs face increasing shortfalls in year-to-year 

revenues over the next decade. CBO estimated in August 2012 that, to 

maintain current spending levels from 2012 to 2022, the Highway Trust 

Fund would require an additional $110 billion over what it is expected to 

take in during that period (see fig. 3). These shortfalls are expected to 

increase as passenger vehicle fuel economy improves and the amount of 

revenue generated per mile traveled decreases. When federal fuel taxes 

were last increased in 1993, the National Highway Traffic Safety 

 

14In addition, drivers also pay an average of 23.3 cents per gallon in state gasoline taxes; 

rates range from 8 cents per gallon in Alaska and Georgia to 39.2 cents per gallon in 

North Carolina. Some states also levy additional taxes and fees on the sale of gasoline 

and diesel fuel, which increases the effective tax rate per gallon. 
 

Page 8 GAO-13-77 Highway Trust Fund

Administration’s Corporate Average Fuel Economy (CAFE) standards 

required newly manufactured passenger cars and light trucks to meet 

estimated average fuel economy levels of 27.5 miles per gallon (mpg) 

and 20.4 mpg, respectively. Current CAFE standards will require 

manufacturers’ new passenger cars and light trucks to have an estimated 

combined average fuel economy of 34.1 mpg by model year 2016,

15 and

as high as 54.5 mpg by 2025.

16 We have previously reported that, over 

the long term, vehicles will become more fuel efficient and increasingly 

run on alternative fuels. Consequently, fuel taxes may not be a long-term 

source of transportation funding.17

Figure 3: Projected Highway Trust Fund Balance, 2012 to 2022

Note: This projection assumes no further appropriations after 2014 from general revenues to the 

Highway Trust Fund.

 

1549 C.F.R. Parts 531, 533, as amended by Light-Duty Vehicle Greenhouse Gas Emission 

Standards and Corporate Average Fuel Economy Standards. 75 Fed. Reg. 25324 (2010). 

162017 and Later Model Year Light-Duty Vehicle Greenhouse Gas Emissions and 

Corporate Average Fuel Economy Standards, 77 Fed. Reg. 62624, 62627 (Oct. 15, 2012), 

errata issued, 77 Fed. Reg. 64051 (Oct. 18, 2012), 77 Fed. Reg. 68070 (Nov. 15, 2012). 

17GAO-11-918. 
 

Page 9 GAO-13-77 Highway Trust Fund

The amount of federal fuel taxes paid by drivers of passenger vehicles 

comprises only a small portion of these users’ overall fuel expenditures 

and varies based on fuel economy. More fuel-efficient passenger vehicles 

pay less in fuel taxes per mile because they require less fuel to travel the 

same distance as less efficient vehicles. The 2009 National Household 

Transportation Survey found that the average one-vehicle household 

spends more than $1,400 annually on gasoline.18

Figure 4: Average Annual Federal Fuel Taxes Paid by Passenger Vehicles

Drivers of sedans with 

average fuel efficiency (22 mpg) pay about $100 per year in federal fuel 

taxes. The driver of a sport utility vehicle (SUV) with a fuel efficiency of 16 

mpg pays about $132 a year in federal fuel taxes (see fig. 4).

Note: Assuming 11,489 miles driven annually (per FHWA 2010 Highway Statistics).

 

18The National Household Transportation Survey (NHTS) includes information on the 

household-based vehicle fleet, including the fuel efficiency of each vehicle, annual miles of 

vehicle use, the resulting amount of gallons of gasoline consumed, and the average cost 

of gasoline at the household location during the interview period. The most recent NHTS 

was collected from April 2008 through April 2009. The average cost for a gallon of 

gasoline during that 13-month period was $2.96, although prices reached as high as $4.00 

in that period. FHWA, 2009 National Household Travel Survey (Washington, D.C., June 

2011). 

Users’ Fuel Tax Costs
 

Page 10 GAO-13-77 Highway Trust Fund

A single commercial truck contributes more to the Highway Trust Fund, 

on average, than a single passenger vehicle for several reasons. The 

federal diesel fuel tax is higher than the gasoline tax, and commercial 

trucks tend to travel more miles annually and are considerably less fuel 

efficient than passenger vehicles. According to FHWA highway statistics, 

the average commercial truck and trailer combination (combination truck) 

traveled nearly 70,000 miles in 2010 while the average passenger vehicle 

traveled about 11,000 miles. Also, while the average combination truck 

traveled about 6 miles per gallon of diesel fuel in 2010, the average 

passenger vehicle traveled about 22 miles per gallon of gasoline. There is 

also a great deal of variation in the amount of fuel taxes paid among 

different configurations of commercial trucks. As shown in figure 5, a 

combination truck with a fuel efficiency of 5 mpg would have paid more 

than 8 times as much in federal diesel fuel tax as a single-unit truck with a 

fuel efficiency of 8 mpg, a difference due primarily to combination trucks 

driving substantially more miles than smaller, single-unit trucks.19

Figure 5: Annual Federal Fuel Taxes Paid by Commercial Trucks in 2010

Although a single commercial truck generally contributes larger amounts 

to the Highway Trust Fund through federal diesel fuel and other taxes, 

FHWA has estimated that commercial trucks pay less than their share for 

their use of our nation’s roadways in relation to the road damage they 

impose. According to research conducted by the American Association of 

 

19Single-unit trucks have a single frame, two axles, and at least six tires or a gross vehicle 

weight rating exceeding 10,000 pounds.
 

Page 11 GAO-13-77 Highway Trust Fund

State Highway Transportation Officials (AASHTO), highway wear 

increases exponentially with the weight of a vehicle’s axle load.20 To 

evaluate the equity and efficiency of highway user fees, FHWA has 

compared the Highway Trust Fund contributions of different vehicle 

classes with the costs attributable to each class as part of its Highway 

Cost Allocation Study. FHWA completed its most recent cost allocation 

study in 1997 in response to a GAO recommendation and provided an 

updated addendum in 2000.21 This study found that in general, lighter 

vehicles pay more than their share of highway costs while heavier 

vehicles pay less than their share. For example, according to FHWA’s 

2000 study, the heaviest combination trucks—those that weigh more than 

the federal interstate gross vehicle weight limit of 80,000 pounds—paid 

50 cents for every dollar’s worth of damage they caused.22 According to 

the AASHTO study that is used as the basis for the organization’s 

pavement design guides, a commercial truck with five axles weighing 

80,000 pounds imposes roadway damage equivalent to the damage 

imposed by 24,000 passenger cars.

In recent years, the federal government and several states have taken 

steps to evaluate mileage fee systems, although none of these U.S.-

based pilot projects has collected fees from drivers based on their road 

use:

 

20From 1958 to 1960, AASHTO conducted road tests to determine the relationships 

between axle weights and pavement wear. The tests showed, for example, that an axle 

weight of 30,000 pounds causes 8 times more pavement damage than an axle weight of 

18,000 pounds. The relationships developed from these tests are still used today to 

attribute pavement wear to various vehicle types.

21In 1994, GAO recommended that FHWA conduct an updated highway cost allocation 

study utilizing data on the relationship between axle loads and pavement damage to 

determine whether all highway users were paying their fair share of federal highway costs. 

GAO, Highway User Fees: Updated Data Needed to Determine Whether All Users Pay 

Their Fair Share, GAO/RCED-94-181 (Washington, D.C.: June 7, 1994).

22FHWA’s 2000 highway cost allocation study estimated costs attributable to each vehicle 

class using a process that considers how physical and operational characteristics of each 

vehicle class affect the design of various components of the highway system or the rate at 

which pavements, bridges, and other elements of the highway infrastructure wear out and 

must be repaired or replaced. According to FHWA, a vast body of research has 

demonstrated the relationship between axle loads and pavement wear and that heavy 

axle loadings contribute significantly to costs for rehabilitating and reconstructing 

pavements.

Mileage-based User Fee 

Initiatives in the United 

States and Abroad
 

Page 12 GAO-13-77 Highway Trust Fund

• In 2005, Congress authorized $16.5 million for a field test for 

assessing highway use fees to vehicles based on their mileage driven 

and using satellite-enabled, on-board units.23 Led by researchers at 

the University of Iowa, the National Evaluation of Mileage-based Road 

User Charges (referred to as the “Iowa study” in this report) tested 

mileage fee systems in the vehicles of 2,600 volunteer study 

participants in 12 states.24

• In 2005 and 2006, respectively, the Puget Sound Regional Council— 

the metropolitan planning organization for the Seattle, Washington 

region—and the Oregon DOT each conducted pilot programs that 

were funded in part by FHWA’s Value Pricing Pilot Program.25 Similar 

to the Iowa study, both pilots tested GPS-based systems installed into 

the vehicles of paid volunteers to gather mileage data and calculate 

hypothetical user fees.

At the time of our review, the Minnesota and Nevada DOTs were testing 

different approaches to calculating mileage fees for passenger vehicles, 

discussed later in this report. The Oregon DOT also conducted field tests 

of a system to collect mileage fees from commercial trucks and has 

planned a new pilot project to examine mileage fees for electric 

passenger vehicles. For a summary of U.S.-based pilot projects, see 

appendix II.

Internationally, several countries have implemented distance-based user 

fee programs for commercial trucks, including Germany, New Zealand, 

Switzerland, Austria, the Czech Republic, and Slovakia.26

 

23SAFETEA-LU §§ 1919 (a), (d), 1934, 119 Stat.,1479-1480, 1490.

These 

programs were designed to address a variety of policy goals, including 

raising revenues and reducing harmful emissions. The New Zealand 

system also charges diesel-fueled passenger vehicles for distances 

24The final report was prepared for the U.S. DOT in 2011 and delivered to Congress in 

April 2012.

25FHWA’s Value Pricing Pilot Program, as authorized under SAFETEA-LU, § 1604(a), 119 

Stat., 1449-1450, encourages the implementation and evaluation of value pricing pilot 

projects to manage congestion on highways through tolling and other pricing mechanisms. 

26Although these countries refer to their programs by different names and may charge 

their user fees based on kilometers driven, rather than miles driven, we refer to these 

programs generally as mileage fee programs in this report.
 

Page 13 GAO-13-77 Highway Trust Fund

traveled. The Netherlands attempted to implement a nationwide 

commercial truck and passenger vehicle mileage fee system scheduled to 

begin in 2012, but the program was suspended before it was 

implemented because of privacy concerns discussed later in this report.

Prior GAO work has found that the design of user fee programs can be 

evaluated based on several related criteria: efficiency, equity, revenue 

adequacy, and administrative burden, as discussed in appendix III.27

These criteria interact and are often in conflict with each other; as such, 

there are trade-offs to consider among the criteria when designing a fee. 

For example, the current method of collecting federal fuel taxes presents 

little administrative burden because these taxes are collected from a 

small number of companies that store or distribute fuel at the wholesale 

level.28 However, according to CBO, fuel taxes also raise efficiency and 

equity concerns in that they: (1) do little to promote the efficient use of the 

nation’s roadways because they provide minimal incentive for users to 

drive less and (2) tend to be regressive, in that they impose a larger 

relative burden on low-income than on high-income households.29

The implementation of mileage fee systems may also be evaluated 

against several widely accepted principles for protecting the privacy and 

security of personal information. These principles, known as the Fair 

Information Practices, include collection limitation, data quality, purpose 

specification, use limitation, security safeguards, openness, individual 

participation, and accountability.

Consequently, every user fee design will have pluses and minuses, and 

no design will satisfy everyone on all dimensions.

30

 

27

In prior work, we noted that these 

principles, with some variation, are used by organizations to address 

privacy considerations in their business practices and are also the basis 

GAO-08-386SP. 

28Recent research by the National Cooperative Highway Research Program (NCHRP) 

suggests that the administrative costs of the collection of state fuel taxes are about 1 

percent of the revenues collected. See NCHRP, Costs of Alternative Revenue-Generation 

Systems, Report 689 (Washington, D.C., 2011).

29CBO, Alternative Approaches to Funding Highways, Pub. No. 4090 (Washington, D.C., 

March 2011).

30See app. IV for information on the Fair Information Practices. 

Evaluating User Fees
 

Page 14 GAO-13-77 Highway Trust Fund

of privacy laws and related policies in the United States, the European 

Union, Australia, and New Zealand.31

Mileage fee initiatives in the United States and abroad show that several 

approaches are available to gather mileage data and charge fees. Some 

approaches could lead to more equitable and efficient use of roadways; 

however, significant privacy-related concerns from the public and cost 

challenges have been raised in applying mileage fees to passenger 

vehicles. Reliable cost estimates for mileage fee systems are not 

available; but launching and operating a system to collect fees from 230 

million U.S. passenger vehicles is expected to greatly exceed the current 

costs of collecting federal fuel taxes. Commercial truck user fee systems 

in Germany and New Zealand show that considerable revenues and other 

benefits can be achieved by charging these vehicles, but enforcing 

compliance in a cost-effective manner presents trade-offs. Only limited 

research has been done to evaluate commercial truck mileage fees in the 

United States. Recent efforts in two states suggest that charging mileage 

fees to commercial trucks presents several benefits over passenger 

vehicle fees, including fewer privacy-related concerns and cost 

challenges.

The five U.S.-based pilot projects that we reviewed and New Zealand’s 

passenger vehicle mileage fee program illustrate three general 

approaches that are currently available to gather mileage data and 

charge drivers user fees.32

 

31GAO, Privacy: Alternatives Exist for Enhancing Protection of Personally Identifiable 

Information, 

The approaches vary in terms of the specificity 

of the mileage data collected as well as the procedures used to charge 

drivers fees. The three approaches are a GPS-based system; a pay-atthe-pump system; and a prepaid, manual system, as depicted in figure 6 

and described in more detail below.

GAO-08-536 (Washington, D.C.: May 19, 2008).

32The five U.S. pilot projects we reviewed were the Iowa study; the Oregon Road User 

Fee Pilot Program; the Puget Sound Regional Council’s Traffic Choices Study; the 

Minnesota DOT Road Use Test; and the Nevada DOT VMT Fee Study. See app. II for a 

brief summary of each.

Various Initiatives 

Demonstrate Mileage 

Fee Benefits, but 

Privacy Concerns and 

Cost Challenges 

Hinder Passenger 

Vehicle Systems

Several Different 

Passenger Vehicle Mileage 

Fee Approaches Exist
 

Page 15 GAO-13-77 Highway Trust Fund

Figure 6: Depiction of Three Passenger Vehicle Mileage Fee Approaches

To implement mileage fees using GPS, the vehicle must be installed with 

an on-board unit with a GPS chip to receive signals from a satellite to 

determine the vehicle’s location. Two types of GPS-based systems can 

be used to calculate mileage fees. One system has sufficient processing 

capability to calculate mileage fees in the vehicle (known as a “thick 

client”); the other system (known as a “thin client”) has less processing 

capability and sends the location data to a central office where mileage 

fees are calculated. Three of the five U.S.-based pilot projects we 

reviewed tested on-board thick-client units, one used a thin-client unit, 

and one did not use GPS.33

 

33The pilot projects using thick-client systems were the Iowa study, Minnesota DOT’s 

Road Use Test, and Oregon’s Road User Fee Pilot Program, which also used pay-at-the 

pump technology in conjunction with a GPS receiver. The Puget Sound Regional Council 

used a thin-client GPS system. The Nevada DOT system does not use GPS.

Thick-client systems transmit summary 

information on the total miles driven by jurisdiction and the amount due to 

a central office, which then prepares the participant’s mileage fee 

GPS-based Mileage Fee 

Systems
 

Page 16 GAO-13-77 Highway Trust Fund

invoice.34

Two states, Nevada and Oregon, have designed mileage fee collection 

systems that resemble the way in which fuel taxes are currently paid—at 

the filling station. The Nevada DOT is currently conducting a pilot project 

that does not require an on-board GPS system and that estimates a 

driver’s mileage fee based on the fuel efficiency of the vehicle and the 

amount of fuel purchased at the pump. To do so, a wireless transponder 

is installed in the participant’s vehicle and connected to the vehicle’s onboard diagnostics unit to gather the total mileage of the vehicle. When a 

vehicle pulls up to a fuel pump at a gas station participating in the pilot, 

the transponder in the vehicle sends the vehicle’s mileage information to 

a transponder installed at the fuel pump. The vehicle’s mileage 

information is then transmitted to a central office where a mileage fee is 

calculated and transmitted back for inclusion in the price of fuel and 

shown on the participant’s fuel receipt. In 2006, the Oregon DOT tested a 

similar pay-at-the pump system, but its system also required a GPS 

receiver

Thin-client systems work similarly, but rather than sending a 

summary of the mileage traveled to a central office, they send detailed 

vehicle location and time-of-day data. The central office uses the data to 

calculate and prepare the participant’s mileage fee invoices.

35 in participant vehicles to charge drivers different fee rates 

based on the jurisdiction of travel (in state, out of state, or within the 

Portland metropolitan area).36

A prepaid manual system is a nonautomated mileage fee system where 

drivers purchase a license that permits them to drive for the purchased 

number of miles, as used in New Zealand’s Road User Charge (RUC) 

system. The RUC system was originally designed to collect user fees 

 

34To calculate fees in the vehicle, thick-client units are preloaded with map files that may 

have fee rates for each jurisdiction (state, county, city) to allow for different charges based 

on location. The unit determines the total number of miles driven in each jurisdiction to 

calculate the total fee. 

35GPS receivers receive signals but do not transmit wide area signals whereas GPS 

navigational units do both, thus enabling third-party tracking of vehicle movements. The 

GPS receivers that Oregon DOT used in its pilot program did not have the ability to track 

vehicle movements.

36Although the Oregon DOT concluded that this pilot was successful and could be 

implemented at a reasonable cost, the department has since revised its technical 

approach and is working to develop a new system that will not mandate the use of a GPS 

receiver and will focus on the collection of user fees from electric-powered vehicles, which 

currently do not pay state or federal fuel taxes. 

Pay-at-the-Pump Mileage Fee 

Systems

Prepaid Manual Mileage Fee 

Systems
 

Page 17 GAO-13-77 Highway Trust Fund

from commercial trucks, but it also applies to diesel-fueled passenger 

vehicles, which comprise 15 percent of all light vehicles in the country. 

New Zealand does not tax diesel fuel at the pump because a significant 

amount is used for off-road purposes that do not impose costs on public 

highways—such as agriculture, construction, fishing, and logging. Vehicle 

owners purchase a RUC license for a range of kilometers (such as 5,000 

to 10,000 kilometers) based on their odometer reading, and the RUC 

license shows the distance the vehicle is permitted to drive. Vehicle 

owners must display the RUC license on the windshield to verify 

compliance during safety inspections or if a vehicle is pulled over for 

traffic a violation. RUC licenses are purchased in 1,000-kilometer 

increments at a variety of locations including post offices, some filling 

stations, and through the New Zealand Transport Agency, which 

manages the program. Unlike the pay-at-the-pump system, New 

Zealand’s RUC system can be used to collect mileage fees from electric 

and alternative fueled vehicles that do not visit fuel pumps but do use 

roads.37 The RUC system was the only passenger vehicle system we 

reviewed that collects actual revenues and the only national mileage fee 

system that applies to passenger vehicles.

The three approaches offer different benefits and challenges and present 

trade-offs to policymakers in evaluating mileage-based user fees. GPSbased systems can lead to more equitable and efficient use of roadways 

by charging drivers based on their actual road use and by providing 

pricing incentives to reduce road use. However, public perception of 

privacy risks raised by these systems significantly limits acceptance of the 

program. Conversely, because pay-at-the-pump and prepaid manual 

systems do not collect location data on drivers they present fewer 

privacy-related challenges, but the trade-offs are reductions in the 

efficiency and equity of the proposed systems. For example, they are 

unable to improve the efficiency of road use by charging drivers different 

rates for travel on specific roadways or during congested periods. Manual 

systems could also be subject to odometer fraud and evasion, with 

compliant drivers paying more than noncompliant drivers. Because 

reliable cost estimates for implementing any of these systems are not 

available, the ability to weigh the costs of implementing and operating a 

 

37Electric vehicles are currently exempt from RUC, but New Zealand officials reported that 

this would change if their numbers became significant.

Benefits and Challenges of 

Passenger Vehicle Mileage 

Fee Systems
 

Page 18 GAO-13-77 Highway Trust Fund

system is a challenge that applies across each of the options. See table 1 

for a summary of the benefits and challenges.

Table 1: Benefits and Challenges of Mileage Fee Systems

Mileage fee systems Benefits Challenges 

GPS systems Opportunity to improve the efficiency of road use 

through variable pricing, or charging road users a 

higher rate during peak traffic times and a lower 

rate during times with light traffic.

Ability to improve equity by accurately pricing road 

use for all users and vehicle types consistent with 

the costs imposed. 

Perception of government intrusion on privacy by 

tracking privately owned vehicles and risk of data being 

compromised or disclosed for unauthorized uses.

High start-up and ongoing costs associated with unit 

installation, implementation, billing, revenue collection, 

and enforcement. 

Pay-at-the-pump 

systems

Alleviates some privacy-related concerns of 

tracking privately owned vehicles by not requiring 

the use of a GPS system.

Cost and logistical challenges associated with the

installation and management of equipment at gas 

stations nationwide and installation of transponders in 

vehicles.

Unable to gather driving data needed to implement 

variable pricing based on congestion to encourage 

efficient road use.

Not compatible with alternative fuel vehicles that do not 

use gas stations. 

Prepaid manual 

systems

Alleviates privacy-related concerns of tracking 

privately owned vehicles by not requiring the use 

of GPS system.

Limits administrative costs by eliminating the need 

to outfit vehicles or fuel pumps with the necessary 

technology to collect total miles traveled.

Unable to gather driving data needed to implement 

variable pricing to encourage efficient road use.

Increased risk of evasion through odometer tampering 

creates equity issues.

Source: GAO analysis.

Using a GPS device to charge passenger-vehicles mileage fees raises 

significant privacy-related concerns among the public. In the surveys 

conducted through the Iowa study, researchers found that after 

completing the pilot, 60 percent of the volunteer participants believed that 

the government would use the information collected to track their 

movements. In addition, state DOT officials conducting public outreach 

and opinion research in Minnesota, Texas, and Nevada found that the 

public expressed a variety of privacy-related concerns, including that the 

government would use a GPS system to track a driver’s movements and 

that the personal information collected could be vulnerable to security 

breaches or shared with law enforcement agencies and private 

companies. According to our survey of state DOTs, 45 of 51 officials 

reported that addressing privacy-related concerns would present a great 

challenge to developing a mileage fee program in their state. Several 

state DOT officials have proposed that using the private sector to manage 

mileage fee programs would alleviate public perception of privacy risks by 

Privacy Challenges 
 

Page 19 GAO-13-77 Highway Trust Fund

limiting the government’s role in collecting and managing personal 

information. However, we have previously reported that by allowing 

private companies access to location data, users can be exposed to 

privacy risks, including disclosure of the location data to unknown third 

parties for unspecified uses, consumer tracking, identity theft, threats to 

physical safety, and surveillance.38

Because of public perception of privacy risks, Oregon and Nevada 

adopted an approach that does not require the use of GPS-based 

systems in future pilots and the Netherlands suspended its mileage fee 

initiative. Oregon DOT officials stated that a government-mandated GPS 

device installed in a vehicle to track and charge for the vehicle miles 

traveled is no longer feasible because of public privacy-related concerns. 

As a result, the Oregon DOT is conducting an alternative pilot program 

that does not mandate the use of a GPS device and provides users 

several options of reporting and paying for miles traveled.39

 

38GAO, Mobile Device Location Data: Additional Federal Actions Could Help Protect 

Consumer Privacy, 

In designing 

its pilot project, the Nevada DOT received negative public feedback over 

the use of GPS devices to determine miles driven. As a result, Nevada 

DOT is testing a pay-at-the-pump system which, according to officials, 

alleviates the public’s privacy-related concerns. Similarly, a commercial 

truck and passenger vehicle user fee system that was scheduled to begin 

in 2012 was suspended by the Dutch government before it could be 

implemented. Dutch officials stated that negative media coverage of the 

program’s potential to invade personal privacy led to public uncertainty 

about the program and subsequent opposition from a number of political 

parties. Consequently, the government deemed the user fee program too 

controversial and suspended it. Furthermore, concerns with mileage fee 

systems have informed congressional debate. In June 2012, the House of 

Representatives included a provision in its fiscal year 2013 appropriations 

bill for the U.S. Department of Transportation that would have prevented 

the Secretary of Transportation from using any of the funds made 

GAO-12-903 (Washington, D.C.: Sept. 11, 2012).

39The options include an on-board unit that does not use GPS and only collects and 

reports undifferentiated miles; a unit with a GPS receiver that reports miles by location; or 

a flat annual or biannual tax that does not require the collection of any mileage data and 

allows the driver to accumulate unlimited miles.
 

Page 20 GAO-13-77 Highway Trust Fund

available under that legislation to research or implement a system that 

would levy a fee on a vehicle user based on the distance traveled.40

Pay-at-the-pump or prepaid manual systems address privacy-related 

concerns to some extent by not tracking a driver’s location; however, 

these systems can reduce some of the efficiency and equity benefits of 

mileage fee systems. For example, variable pricing programs that charge 

road users a higher rate during peak traffic times and a lower rate during 

times with light traffic can be facilitated through the use of GPS systems. 

In theory, GPS could also be used to charge drivers different rates based 

on the type of road or the location of travel, such as higher rates on urban 

Interstates and lower rates on rural roads. The system in place in New 

Zealand and the one being tested in Nevada only collect total mileage 

driven by the vehicle and are unable to apply different fees based on time 

and location. In addition, pay-at-the pump systems cannot charge electric 

fuel vehicles since they do not need to use gas stations to power their 

vehicles. Also, equity issues caused by odometer fraud exist in prepaid 

manual systems. For example, New Zealand officials reported that when 

a passenger vehicle is pulled over for a violation, the police have no way 

to determine whether an odometer has been disabled and that mileage is 

not being recorded. An independent review of the RUC program 

conducted in 2008 estimated that about $10 million (U.S.), or 6 percent of 

the light vehicle RUC revenue, was lost because of evasion.41

Reliable estimates for start-up and ongoing administrative costs of a 

passenger vehicle mileage fee system in the United States are currently 

unknown but are likely to be substantial.

New 

Zealand government officials noted that as a result, compliant drivers pay 

higher RUC rates than they otherwise would to replace the revenues lost 

from noncompliant drivers.

• Start-up costs: Installing on-board units in 230 million U.S. passenger 

vehicles would almost certainly be a significant cost challenge. 

Reliable estimates for the current cost of purchasing and installing onboard units for all U.S. passenger vehicles are not available, but such 

 

40H.R. 5972, § 419, 112th Cong. (2012).

41Odometer fraud is an illegal practice that consists of decreasing the number of miles 

reported by a vehicle’s odometer by disabling or turning back the odometer ‘s reading to 

appear that a vehicle has lower mileage than what was driven. 

Cost Challenges 
 

Page 21 GAO-13-77 Highway Trust Fund

costs are likely to greatly exceed the current costs of collecting fuel 

taxes, estimated at about 1 percent of the revenues collected. A May 

2009 study, prepared for U.S. Department of Transportation on the 

administrative costs of collecting highway revenues, found that the 

costs of purchasing and implementing a GPS-based mileage fee 

system could range from roughly 8 percent to 33 percent of the 

revenues generated over a 20-year period, depending on the type of 

system used. The German government estimated the current cost of 

the GPS-enabled on-board units used in its commercial truck user fee 

system to be about $240 per unit, with additional costs for 

installation.42 These start-up costs would likely be prohibitive if the 

goal of the fees is to replace current federal fuel tax revenues, which 

are about $100 per year for the driver of a sedan with average fuel 

efficiency. Similarly, retrofitting thousands of gas stations to support a 

pay-at-the pump system would be costly and challenging. For 

example, the Oregon and Nevada pay-at-the-pump pilot programs 

cited difficulties finding and recruiting gas stations to participate in 

their pilot programs.

• Ongoing administrative costs: The costs of managing, maintaining,

and enforcing any mileage fee system are also unknown but likely to 

be substantial. For example, a 2011 report analyzing cost estimates 

from the proposed mileage fee system in the Netherlands estimated 

the total operating costs to be about 7 percent of the revenues 

projected to be generated by that system.43

 

42The cost per unit for the U.S. vehicle fleet would likely be substantially lower because 

unit costs would be expected to decrease with more units purchased.

However, the report found 

that operating costs as a percentage of revenues could be 

substantially higher in the United States because U.S. drivers pay 

substantially less in transportation costs than drivers in the 

Netherlands. Furthermore, the ongoing maintenance of on-board units 

could be costly and present technical challenges. In the Iowa study, 

approximately 24 percent of the 2,600 participants experienced at 

least one study-related problem with their vehicle or installed 

equipment over the 2-year study period, and a total of 618 incidents 

required at least one service visit to correct. Of these incidents, 79 

percent were due to a problem with the performance of installed onboard units. The principal researcher on the project stated that this 

43See National Cooperative Highway Research Program, Costs of Alternative RevenueGeneration Systems, Report 689 (Washington, D.C., 2011).
 

Page 22 GAO-13-77 Highway Trust Fund

level of error would have been “disastrous” and would have 

jeopardized the success of a national mileage fee rollout with millions 

of vehicles involved. The Iowa study recommended that the federal 

government should fund a larger, national mileage fee study that 

would generate the efficiencies needed to provide an accurate 

estimate for back-office operational costs.

Germany’s Heavy Goods Vehicle (HGV) system was implemented in 

January 2005 and is the first distance-based user fee system in Europe to 

use GPS technology.44

 

44Switzerland, the Czech Republic, Slovakia, and Austria each have also implemented a 

commercial truck distance-based user fee system. 

The program was developed through a publicprivate partnership between the German government and a private sector 

company, which manages and collects tolls for the German government. 

The HGV system charges all trucks weighing more than 12,000 kilograms 

(over 26,000 pounds), regardless of national origin, a per-kilometer fee to 

travel on the 12,700-kilometer (almost 8,000-mile) national motorway, or 

autobahn. Currently, about 700,000 trucks across Europe are equipped 

with GPS-based on-board units that meter all travel on the autobahn. The 

on-board units use cellular communications to transmit mileage data to 

the private toll operator, which is responsible for billing trucking firms and 

collecting the fees. Approximately 700,000 other commercial trucks 

without on-board units are charged user fees through a manual booking 

system maintained by the private toll operator. Users of this system must 

prepay for their travel through the Internet or at 3,500 electronic toll 

terminals located at various entry points and service areas across the 

autobahn.

Commercial Truck User 

Fee Programs in Germany 

and New Zealand Have 

Raised Substantial 

Transportation Revenues 

and Produced Other 

Benefits 

Revenues and Benefits from 

Germany’s Heavy Goods 

Vehicle User Fee System 
 

Page 23 GAO-13-77 Highway Trust Fund

The goals of the HGV system were to (1) raise transportation revenues 

through the user pays principle and to (2) reduce harmful emissions from 

commercial trucks. The program has generally achieved its goal of raising 

new revenues by ensuring that both foreign and domestic trucks on the 

autobahn are charged equitably for their travel. According to German 

transportation officials, foreign trucks account for more than 35 percent of 

the country’s truck travel. Prior to the launch of the HGV system, foreign 

trucks could purchase diesel fuel in neighboring countries to avoid 

Germany’s significant fuel taxes, and thus use German roadways without 

contributing revenues for their maintenance. The HGV tolling system

addresses this by charging all trucks subject to the tolls, regardless of 

national origin, the same per-kilometer fees to travel on the autobahn. 

From fiscal year 2007 through 2011, the HGV system raised almost $25 

billion (more than 20 billion euros) in dedicated surface transportation 

revenues from an estimated 1.4 million commercial truck users.45

The program also achieved its second goal of creating incentives for 

operators to invest in lower emission vehicles, which has resulted in 

reduced emissions across the German and European trucking fleet. User 

fee rates are variable and based on the truck’s emission class, number of 

axles, and distance traveled on the roads subject to the fee. Trucks with 

lower emissions pay significantly less than trucks with higher emissions, 

with rates ranging from 28 to 57 U.S. cents per mile. The composition of 

the HGV trucking fleet has changed dramatically over the course of the 

program as a result of the variable pricing incentives. In 2005, the lowest 

emission commercial truck classes, known as the Euro 5 and enhanced 

environmentally-friendly vehicle emissions categories, comprised less 

than 1 percent of the commercial trucking fleet. By the end of 2011, those 

classes comprised about 70 percent of the commercial truck fleet. 

German transportation officials reported that while this outcome was a 

positive environmental benefit, the fast turnover of the vehicle fleet 

resulted in slightly lower-than-expected revenues because lower emission 

vehicles pay lower rates. Consequently, the German government 

reviewed and raised the rates across all categories while maintaining the 

incentives for lower emission vehicles.

The New Zealand RUC program was established in 1977 and requires 

that owners of vehicles over 3,500 kilograms (7,700 pounds), including 

 

45Euro to dollar conversions are based an exchange rate of .8198 on July 30, 2012. 

Revenues and Benefits from 

New Zealand’s RUC Program 
 

Page 24 GAO-13-77 Highway Trust Fund

trucks and their trailers, prepurchase a RUC license for all miles traveled 

on the nation’s 94,000-kilometer (58,000-mile) public roadway system. As 

with diesel passenger vehicles, commercial trucks purchase RUC 

licenses in 1,000-kilometer increments and must display the license and 

the kilometers permitted on their windshield. The government has 

provided an option for vehicle owners to install electronic RUC (E-RUC) 

systems that are provided by private sector firms certified by the New 

Zealand government to collect fees and remit revenues to the 

government. The E-RUC system uses on-board GPS units to keep track 

of the status of each vehicle’s RUC license and whether additional 

kilometers need to be purchased. Trucking firms that subscribe to the 

system can track their fleet’s RUC licenses online and may purchase 

additional applications enabled by GPS to track the location, speed, and 

fuel efficiency of their trucks. Commercial trucks, rather than passenger 

vehicles, are the vast majority of E-RUC users because of the higher cost 

of subscribing to E-RUC systems compared with lower costs of 

purchasing prepaid paper RUC licenses directly from retailers.

The primary goal of the RUC program is to generate surface 

transportation revenues from heavy vehicles by charging users fees that 

reflect the maintenance costs that these vehicles impose on the 

roadways. Because highway wear increases exponentially with the weight 

of a vehicle’s axle load, the RUC system uses variable pricing to charge 

higher rates to heavy trucks with fewer axles, and lower rates to heavy 

trucks with more axles. For example, a three-axle truck weighing more 

than 18 tons (almost 40,000 pounds) is charged almost 43 U.S. cents per 

mile, while a truck of the same weight with five or more axles is charged 

35 U.S. cents per mile.46

 

46Additional charges would apply for trailers, which must also be licensed separately from 

powered trucks towing them and carry their own distance recorders.

All miles for light passenger diesel vehicles are 

charged at a flat rate of less than 6 U.S. cents per mile regardless of the 

actual vehicle weight. This is because an individual light vehicle causes 

only very limited amounts of wear on the road compared with heavy 

trucks, and the variation in wear among light vehicles of different weights 

is also minimal. From 2007 through 2011, the RUC system generated 

about $3.4 billion (U.S.) in dedicated surface transportation revenues, 
 

Page 25 GAO-13-77 Highway Trust Fund

with 74 percent coming from heavy trucks and 26 percent from light 

passenger vehicles.47

The New Zealand RUC program has achieved a related program benefit 

of promoting the use of trucks that cause less damage to roadways, an 

outcome that may reduce road maintenance costs. According to New 

Zealand government officials, the variable pricing incentives have 

influenced the composition of the commercial truck fleet so that trucks 

with more axles per vehicle weight represent a greater portion of the 

vehicle fleet than in most other countries. For example, according to 2010 

New Zealand Transport Agency data, combination trucks with eight axles 

represented about 35 percent of all trucks on New Zealand roadways. In 

contrast, according to FHWA data, eight-axle combination trucks were 

estimated to account for less than 1 percent of the U.S. truck fleet in 

2000.48

The different approaches taken by Germany and New Zealand illustrate

the trade-offs involved in designing a mileage fee system for trucks that 

provides adequate enforcement in a cost-effective manner. The German 

system employs an extensive but costly roadside enforcement 

infrastructure; New Zealand’s RUC program does not, but it has higher 

estimated evasion rates and revenue leakages than the German system.

New Zealand trucking association representatives reported that 

operators in New Zealand use trucks and trailers with as many as nine 

axles in combination in order to pay lower RUC fees. New Zealand 

government officials reported that this altered vehicle fleet is considered 

to reduce road maintenance costs due to reduced pavement damage, 

although no estimate is available for the overall value of the savings.

The German government and its private sector toll operator ensure 

compliance with the HGV system through significant roadside 

infrastructure and enforcement. The HGV system includes 300 gantries, 

or overhead structures, deployed across the autobahn to ensure that onboard units are operating correctly and that manual users of the system 

 

47New Zealand to U.S. dollar conversions are based on an exchange rate of 1.32 on July 

30, 2012. The total RUC revenues in New Zealand dollars from fiscal years 2007 through 

2011 were $4.47 billion in New Zealand dollars. New Zealand transportation officials 

estimate that in fiscal year 2011, about 10 percent to 15 percent of all commercial truck 

RUC revenues were generated through the E-RUC devices.

48Federal Highway Administration, Comprehensive Truck Size and Weight Study, FHWAPL-00-029 (Washington, D.C., August 2000).

Commercial Truck Mileage Fee 

Systems Face Trade-Offs 

between Cost and Enforcement 

While Acting to Mitigate 

Privacy Concerns 
 

Page 26 GAO-13-77 Highway Trust Fund

have registered for their travel. Each gantry is equipped with enforcement 

cameras and short-range, wireless devices that signal to each passing 

truck’s on-board unit to ensure it is activated and functioning properly.49

The German government staffs a fleet of 250 mobile enforcement 

vehicles equipped by the toll operator, which is used to patrol the 

autobahn and respond to suspected violations.50

Figure 7: German HGV Enforcement Gantry and Mobile Enforcement Vehicle

(See fig. 7.) According to 

officials, this approach has resulted in an estimated evasion rate that is 

less than 1 percent, meaning that less than 1 percent of all HGVs on the 

system were out of compliance in 2011.

Although the German government reported that the HGV system 

experiences very little revenue leakage from evasion, the system is costly 

to implement. All of the start-up costs for implementing the HGV system 

 

49The enforcement cameras capture images of each passing truck and its license plate so 

that the toll operator can verify whether vehicles without on-board units have booked their 

travel for the appropriate segment of the autobahn. 

50The mobile enforcement fleet is equipped with short-range communications devices that 

read a moving truck’s on-board unit to test for compliance. To determine whether users 

without on-board units have registered for their travel, German mobile transport officers 

can query the toll operator’s database of registered users for license plate data to check 

compliance. 
 

Page 27 GAO-13-77 Highway Trust Fund

were incurred by the toll operator, which owns the 700,000 on-board units 

installed across Europe, as well the roadside infrastructure and backoffice equipment used to monitor and enforce the system.51 From fiscal 

years 2007 through 2011, the German government paid the system 

operator approximately $664 million per year to manage the system. 

These administrative costs averaged about 13 percent of the $5 billion in 

average revenues generated annually over that time period. The German 

government also spends almost $62 million per year to staff the mobile 

enforcement vehicles with German police. In addition, Germany allocates 

$740 million annually in HGV revenues for several programs to assist 

German trucking firms in complying with the system. Although these 

compliance programs are not considered to be part of the administrative 

costs of operating the HGV system, they further reduce the net revenues 

generated.52

New Zealand’s RUC fees are collected and enforced manually with little 

roadside enforcement technology and lower costs than the HGV system, 

but with higher estimated evasion rates. The New Zealand national police 

enforce RUC compliance with eight inspection stations across the 

country, staffed with a total of 90 officers nationwide. Commercial trucks 

are required to stop at these stations, and police manually inspect and 

compare the mileage limit on the displayed RUC license with the vehicles’ 

current mileage on special odometers that are mounted on the hubs of 

trucks and trailers.53

 

51Data on the start-up costs are proprietary to the toll operator and were not available for 

this report. However, those costs, and the costs of operating the system are recouped 

through annual, performance-based contractual fees paid by the German government to 

the toll operator.

According to the New Zealand trucking association, 

compliance with these manual inspections is inefficient and costly to 

operators because of time lost. The government reported that the costs of 

managing the RUC program are nearly $18 million (U.S.) per year, or 2.5 

percent of the estimated $700 million (U.S.) generated annually by the 

52According to German transportation officials, these programs are intended to offset the 

costs of compliance to German trucking firms to upgrade to lower emission vehicles, to 

train drivers to comply with the system, and a small program to enhance vehicle safety 

and the environment.

53These “hubodometers” are removable mechanical mileage tracking devices that can be 

mounted on trailers, which are not equipped with odometers, so these vehicles can be 

licensed and charged. 
 

Page 28 GAO-13-77 Highway Trust Fund

system.54 Although these administrative costs are substantially lower than 

the 13 percent costs of the German system, implementing the RUC 

system comes with higher estimated evasion rates than the 1 percent of 

revenues estimated lost in Germany. According to the New Zealand 

Ministry of Transport, roughly 4 percent of the commercial truck revenues 

on average are lost annually because of evasion by trucks. This equates 

to an estimated loss of about $21 million (U.S.) per year from fiscal years 

2007 to 2011, or slightly more than the amount that the New Zealand 

government spends annually to manage the program.55

Germany and New Zealand officials reported they have safeguards in 

place to limit the collection and use of mileage data, and as a result, 

privacy concerns for commercial trucks are not a significant challenge. 

The officials reported that the respective laws that authorize these 

programs stipulate several data protection provisions consistent with 

internationally recognized Fair Information Practices.56

 

54Unlike the arrangement that Germany has with its toll operator, the New Zealand 

government pays nothing to the private sector companies that implement the E-RUC 

system as its revenues are generated from the sale of subscription services to trucking 

firms. 

Both programs are 

required to clearly define and limit the data to be collected, the purpose 

for its collection, the limits for its use, as well as the security safeguards 

that are in place. For example, in Germany, the government and its 

contracted toll operators are permitted to collect, use, and process only 

limited information to enforce the tolls, including a picture of the vehicle, 

the place and time the tolled road was used, and features of the vehicle 

(number of axles) necessary to process the toll. This data must be 

deleted immediately after the toll is paid. Because of the legal safeguards 

in place, commercial trucking associations in Germany and New Zealand 

55New Zealand government officials reported that the 4 percent evasion rate reflects the 

former RUC rules, which were changed in August 2012 in order to reduce noncompliance. 

The RUC system formerly charged on the basis of actual weight as nominated by vehicle 

operators, but this was changed in order to improve compliance and simplify 

administration. As of August 2012, the RUC system charges all vehicles based on their 

maximum gross-laden weight regardless of whether the vehicle is fully loaded or empty. 

56See app. IV for information on the Fair Information Practices. The German Motorway 

Toll Act for Heavy Goods Vehicles (2002) §§ 4(2) and 7(2) establishes limits on the 

specific data that may be collected, processed, and used for the collection and 

enforcement of tolls in the HGV system. The New Zealand Road Use Act of 2012, 

Schedule 1, § 45(3) establishes the duties of E- RUC system providers relating to the 

collection, use and disclosure, and management of RUC data. 
 

Page 29 GAO-13-77 Highway Trust Fund

both reported that the invasion of personal privacy or the loss of 

proprietary business information are not significant concerns among their 

firms. Because the New Zealand RUC system is largely a prepaid manual 

system in which most users do not have an on-board unit, privacy-related 

concerns do not arise. Moreover, safeguards are in place to protect the 

data of the commercial truck fleet using the E-RUC system. According to 

New Zealand government officials, the private companies applying to 

become E-RUC providers are subjected to a stringent series of tests to 

ensure the security of data before the government approves them to act 

as agents for the RUC system. Tests include verification of the providers’ 

data security systems, the accuracy of the data collected, and their 

systems’ ability to identify efforts to tamper with E-RUC units.

Although U.S. initiatives to evaluate mileage fees have focused primarily 

on passenger vehicles, two recent efforts focused on fees for commercial 

trucks. Specifically, the Oregon DOT and several metropolitan planning 

organizations and a consulting firm in New York recently evaluated ways 

to electronically collect existing weight-distance taxes that apply to 

commercial trucks in those states.57

• In 2010, the Oregon Truck Road Use Electronics (TRUE) pilot project 

tested GPS-based units in 25 trucks operated by three trucking firms 

to automate the collection of Oregon’s truck weight-mile tax. Oregon 

officials reported that the devices successfully tracked the miles 

traveled in their state and sent the data to Oregon DOT to produce a 

monthly weight-mile tax statement for the trucking firms participating 

in the pilot, to facilitate their payment of the state’s weight-mile tax.

• In a separate 2010 study, researchers collected GPS routing data 

provided by several trucking firms in New York to test the feasibility of 

using existing GPS-based technology to implement a truck mileage 

 

57Four states (Oregon, New York, Kentucky, and New Mexico) currently levy weightdistance taxes on commercial trucks. Two of these states, Oregon and New York, have 

considered transitioning to an electronic collection of these user fees. In Oregon, all trucks 

over 26,000 pounds must register their highest operating weight for each truck 

combination and self-report the miles traveled in Oregon by each combination. The 

weight-mile tax rates vary in relation to axle load and weight to incentivize the use of truck 

combinations that do less damage to roadways. The taxes are paid on a monthly or 

quarterly basis. New York’s ton-mile tax charges trucks different rates based on whether 

they are hauling cargo (laden weight) or are empty (unladen weight). 

Commercial Truck Mileage 

Fee Pilot Projects in the 

United States Also Suggest 

Benefits 
 

Page 30 GAO-13-77 Highway Trust Fund

fee system that would replace existing state truck fees and taxes. 58

The results of these U.S. pilots suggest that charging mileage-based user 

fees to commercial trucks presents several benefits over passenger 

vehicle fees:

The study found that a mileage fee system could more accurately 

track vehicle mileage than the current system, which relies on selfreported mileage from trucking firms, and could generate an additional 

$150 million in revenue annually that is estimated to be lost because 

of underreporting of mileage and weight.

• Reduced privacy concerns. Some of the privacy-related concerns 

discussed previously with regard to using GPS-based systems for 

passenger vehicles may not be as troublesome if applied to 

commercial trucks because the right of privacy would belong to the 

company that owns the truck. Trucking companies can be required to 

meet reasonable conditions and pay appropriate taxes in exchange 

for using the public highways. They can also set the conditions of 

employment for their employees, who have limited privacy rights 

because employers may establish the policies that govern their 

workplaces and allow the monitoring of the use of any company 

assets, including trucks. Employers may also establish policies that 

inform employees about information collected as a condition of 

employment. The New York commercial truck mileage fee study 

reported that a significant portion of large trucks already have fleet 

management systems that include the GPS technology needed to 

support mileage fees. These fleet management systems are used by 

trucking firms to monitor mileage traveled, driver speed, estimated 

delivery times, and other business performance information.

• Reduced implementation costs. First, because there are significantly 

fewer commercial trucks than passenger vehicles in the United 

States, the overall costs of implementing a truck mileage fee system 

would almost certainly be significantly lower for these vehicles. 

According to FHWA data, commercial trucks represent 4 percent of 

the U.S. vehicle fleet, with a total of about 10 million single-unit and 

combination vehicles on the roadways in fiscal year 2010. Equipping 

trucks with on-board units would be significantly less costly than 

 

58Delcan Corporation, Calmar Telematics, and the Greater Buffalo Niagara Regional 

Transportation Council, A Practical Approach to Truck VMT Fees, Final Report (April 

2011).
 

Page 31 GAO-13-77 Highway Trust Fund

equipping the 230 million passenger vehicles with the same 

equipment. In addition, because combination commercial trucks 

average significantly more miles per year (almost 70,000) than the 

average passenger vehicle (more than 11,000 miles), commercial 

truck mileage fee systems could generate significantly more revenue 

per vehicle than passenger vehicles systems. As such, the costs to 

the government to implement a commercial truck system could be 

recovered faster than costs of implementing a passenger vehicle 

system. 

• Reduced reporting burden on trucks. Mileage fees for commercial 

trucks could be designed to consolidate existing requirements for 

interstate commercial trucks to report their miles traveled in most 

states. Currently, companies registered in states that have 

established, maintained, or enforced the International Fuel Tax 

Agreement (IFTA),59 or in states participating in the International 

Registration Plan (IRP),60 are required to track and report their miles 

traveled in each state to their state of registry.61 IFTA and IRP provide 

for the distribution of state fuel and registration taxes among the 

contiguous 48 U.S. member states and all 10 Canadian provinces 

based on the number of miles driven by trucks in each state or 

province. According to Oregon DOT officials, the reporting 

requirements for these agreements can be administratively timeconsuming, particularly for smaller firms that may not have GPS units 

on board to track their mileage by location. Furthermore, because 

states have different fuel tax rates, firms may inaccurately report their 

mileage traveled, particularly in states with higher fuel tax rates than 

other states. Oregon DOT officials reported that the system tested in 

that state, or other systems currently available on the commercial 

market, could be used to assess mileage fees and simplify IFTA and 

IRP reporting requirements for commercial trucks.

 

5949 U.S.C. § 31705, referring to and permitting states to require fuel use tax reporting 

requirements conforming to IFTA. 

6049 U.S.C. § 31704, referring to and restricting states not participating in IRP.

61IFTA is an interstate agreement for the collection and distribution of fuel taxes. IRP is an 

interstate agreement for the apportionment of registration fees. The Intermodal Surface 

Transportation and Efficiency Act of 1991 encouraged states to participate in these 

agreements. Under these agreements, states collect data on the miles that truck operators 

travel in their state and on registered truck weights. 
 

Page 32 GAO-13-77 Highway Trust Fund

Despite the benefits, opponents of commercial-truck mileage fees in the 

United States reported that such fees would be burdensome on trucking 

firms, costly to collect, and difficult to enforce. Specifically, trucking firms 

would likely incur costs to install mileage fee technology in their vehicles. 

Trucking industry representatives reported that mileage fees would need 

to be collected from more than 500,000 firms operating trucks—90 

percent of which operate six or fewer trucks—and the cost of compliance 

could be particularly burdensome to smaller firms. In addition, fees based 

primarily on self-reported data can be difficult to verify, particularly if the 

data is not collected electronically. Such fees would also require the state 

or federal government to monitor and audit trucking firms to ensure the 

fees reflect the actual mileage logged by each vehicle. Furthermore, 

trucking industry representatives reported that taxes, such as mileage 

fees, that require the government to keep proprietary business data 

without rigorous data protection safeguards in place would be 

unacceptably intrusive. Commercial truck mileage fee opponents also 

reported that the fees could result in inequities among trucking firms, with 

compliant firms paying more than their share of the fees because of any 

noncompliant competitors.

We modeled the average mileage fee rates that would be needed for 

passenger vehicles and commercial trucks to meet three illustrative 

Highway Trust Fund revenue targets ranging from about $34 billion to 

$78.4 billion per year. To meet these targets, a driver of a passenger 

vehicle with average fuel efficiency would pay from $108 to $248 per year 

in mileage fees compared to the $96 they currently pay annually in 

federal gasoline tax. However, these results do not include the initial startup or ongoing administrative costs of a national mileage fee system in the 

United States, which are unknown. Mileage fees, like federal fuel taxes, 

would comprise a small portion of users’ overall fuel costs and thus would 

only marginally increase users’ overall transportation costs. For example, 

drivers of passenger vehicles with average fuel efficiency would pay 7 

percent more than their current costs to achieve the highest revenue 

target of $78.4 billion. Such a change to the fee system, however, would 

affect users’ costs differently based on their vehicle’s fuel efficiency, 

because drivers of less efficient vehicles currently pay more in fuel taxes 

than drivers of vehicles with greater fuel efficiency. Mileage fees for 

commercial trucks would also affect users differently because larger 

trucks tend to be driven more miles and smaller trucks are marginally 

more fuel efficient. Currently, heavier commercial trucks generally 

contribute less to the Highway Trust Fund than the costs of their road 

use. Adjusting the illustrative mileage fee rates to reflect the road damage 

Mileage Fees Could 

Generate Highway 

Trust Fund Revenues 

and Would Affect 

Users Differently
 

Page 33 GAO-13-77 Highway Trust Fund

caused by different vehicles would notably increase commercial truck 

rates and modestly decrease passenger vehicle rates. However, setting 

rates that reflect the current costs that different users impose on the 

system would require up-to-date estimates of vehicles’ responsibility for 

road damage, which are not available.

We modeled three scenarios of average mileage fee rates for passenger 

vehicles and commercial trucks to replace or augment the Highway Trust 

Fund revenues currently generated through federal fuel taxes. These 

scenarios assume that the other federal taxes paid by commercial trucks 

remain in place and do not include start-up or ongoing administrative 

costs:62

1. Replace federal gasoline and diesel fuel tax receipts: In fiscal year 

2010, the latest year for which complete data were available, federal 

gasoline and diesel fuel tax receipts produced nearly $34 billion in 

revenue.63

2. Meet current spending levels: Highway Trust Fund user fee revenues 

have been insufficient to meet authorized spending levels since 2008, 

and further shortfalls are expected in the years ahead. Using fiscal 

year 2010 as an example—a year in which Congress augmented the 

fund with $19.5 billion in general revenues—this scenario models 

 

62The other federal taxes paid by commercial trucks include the federal heavy vehicle use 

tax and the federal tire, truck, and trailer excise taxes, which generated $2.8 billion in 

fiscal year 2010.

63Federal fuel tax receipts totaled almost $34 billion in fiscal year 2010. We attributed the 

$24.8 billion in federal gasoline tax receipts deposited in the Highway Trust Fund to 

passenger vehicles and the $9.1 billion generated through the federal diesel fuel tax to 

commercial trucks. Our model does not consider the small portion of the U.S. passenger 

vehicle fleet powered by diesel fuel. According to the Environmental Protection Agency, 

less than 1 percent of all model year 2010 light duty vehicles in the United States ran on 

diesel fuel and, as result, the amount of federal diesel fuel tax receipts contributed to the 

Highway Trust Fund by passenger vehicles is minimal. It also does not consider that small 

portions of federal gasoline fuel tax receipts are estimated to be derived from use in 

motorboats and small engines, such as lawnmowers and chain saws, and transferred from 

the Highway Trust Fund to other nonhighway accounts.

Using Mileage Fees to 

Generate Highway Trust 

Fund Revenues
 

Page 34 GAO-13-77 Highway Trust Fund

mileage fee rates that could support $53.5 billion in spending.64 This 

revenue target is also roughly equivalent to the average annual 

authorizations for highway and transit programs provided in MAP21.

65

3. Maintain existing conditions and performance levels: According to the 

National Surface Transportation Infrastructure Financing Commission, 

current funding levels will result in further deterioration of the nation’s 

roadways and transit infrastructure. The commission estimated that 

maintaining the existing infrastructure would require an annual federal 

contribution of about $78.4 billion for highways and transit.66

Mileage fee rates for passenger vehicles and commercial trucks would 

vary based on the amount of revenue they are set to generate. To meet 

the federal revenue targets set under the three scenarios we modeled, 

the average passenger vehicle mileage fee rate would range from less 

than 1 cent to more than 2 cents per mile and the average commercial 

truck rate would range from greater than 3 cents to more than 8 cents per 

mile (see table 2). Converting these mileage fee rates to per-gallon 

charges to illustrate their approximate relation to current federal fuel tax 

rates shows that significantly higher fuel taxes would be needed to 

generate the revenue targets we modeled. For example, converting the 

mileage fee rates needed to meet current spending levels ($53.5 billion) 

would translate to a federal gasoline tax of nearly 32 cents per gallon and 

a federal diesel fuel tax of almost 35 cents per gallon, increases of 

 

64The $53.5 billion revenue target in this scenario represents the total budget authority for 

FHWA and the Federal Transit Administration. This amount does not include the $27.5 

billion in general fund revenues identified through the American Recovery and 

Reinvestment Act of 2009 for federal highway infrastructure projects (Pub. L. No. 111-5, 

Title XII, 123 Stat. 115, 206 (Feb. 17, 2009).

65MAP-21 authorized funding for fiscal years 2013 and 2014. According to FHWA and the 

Federal Transit Administration, the total amount of funds authorized for highway and 

transit programs in these years is more than $103 billion.

66In February 2009, the commission reported that annual federal highway and transit 

spending of $59 billion and $19 billion, respectively, would be necessary to maintain the 

existing conditions and performance of our nation’s surface transportation system. 

National Surface Transportation Infrastructure Financing Commission, Paying Our Way: A 

New Framework for Transportation Finance (Washington, D.C., February 2009). After 

adjusting this figure to reflect 2010 dollars and subtracting the $2.8 billion that commercial 

trucks contributed to the Highway Trust Fund in other taxes in fiscal year 2010, this target 

is equal to $78.4 billion in federal fuel tax receipts.
 

Page 35 GAO-13-77 Highway Trust Fund

roughly 72 percent and 43 percent, respectively. For technical details on 

our modeling, see appendix V.

Table 2: Illustrative Federal Mileage Fee Rates for Three Revenue Scenarios

Revenue scenario

Average

passenger vehicle 

mileage fee

(cents per mile)

Comparison with

federal gasoline taxa 

(18.4 cents/gal)

Average

commercial truck 

mileage fee

(cents per mile)

Comparison 

with federal

diesel fuel taxb 

(24.4 cents/gal)

Replace federal fuel tax 

receipts

($34 billion)

0.9¢ n/a 3.2¢ n/a

Meet current spending levels

($53.5 billion)

1.5¢ 31.6¢

(72% increase)

5.4¢ 34.8¢

(43% increase)

Maintain existing conditions 

and performance

($78.4 billion)

2.2¢ 46.6¢

(153% increase)

8.4¢ 53.8¢

(120% increase)

Source: GAO analysis.

NOTE: These results do not include the initial start-up or ongoing administrative costs of a national 

mileage fee system in the United States. Because the results are intended to illustrate the average 

mileage fees that would be needed to replace federal fuel tax receipts, we assumed that all other 

federal commercial truck taxes remain in place. a

Based on 21.6 mpg average passenger vehicle fuel economy.

b

Based on 6.4 mpg average commercial truck fuel economy.

These results do not include the initial start-up or ongoing administrative 

costs of a national mileage fee system in the United States, which are 

unknown but would result in increased rates. To estimate how such costs 

would affect mileage fees, we modeled rates that assumed annual fixed 

costs of 5 percent and 20 percent of current federal fuel tax receipts 

across all scenarios.67 We found that the percentage increase in mileage 

fee rates required to account for costs of implementation is greater with a 

lower revenue target than with a higher revenue target. For example, 

assuming 20 percent administrative costs, mileage fee rates for 

passenger vehicles would need to increase by 27 percent (from 0.9 cents 

to 1.2 cents per mile) to generate $34 billion and by 13 percent (from 2.2 

cents to 2.4 cents per mile) to generate $78.4 billion.

 

67These estimates were based on existing academic literature that has attempted to 

identify the range of costs of implementing a mileage fee system. For details on how we 

modeled mileage fee rates that included administrative costs, see app. I.
 

Page 36 GAO-13-77 Highway Trust Fund

Mileage fees for passenger vehicles would affect users differently based 

on their vehicle’s fuel efficiency because drivers of less fuel efficient 

vehicles currently pay more in fuel taxes, as they have to purchase more 

gasoline to travel the same distance as more efficient vehicles. A system 

that charges all passenger vehicles the same rate would lead to drivers of 

more fuel efficient vehicles paying proportionately more in mileage fees 

than they currently pay in federal fuel taxes. As illustrated in figure 8, a 

driver of a hybrid with a fuel efficiency of 40 mpg would pay twice as 

much in mileage fees under the scenario to replace fuel tax receipts and 

over 4 times as much under the scenario to augment Highway Trust Fund 

revenues to maintain current conditions and performance. In contrast, a 

driver of an SUV with a fuel efficiency of 16 mpg would pay less in 

mileage fees under the scenario to replace federal fuel tax receipts and 

less than twice as much (88 percent more) under the scenario to augment 

Highway Trust Fund revenues to maintain current conditions and 

performance.

Effects of Mileage Fees on 

Users

Passenger Vehicles 
 

Page 37 GAO-13-77 Highway Trust Fund

Figure 8: Average Passenger Vehicle Users’ Annual Federal Fuel Taxes Paid under Current System Compared with Mileage 

Fee Scenarios

Although cost increases for passenger vehicle users appear significant 

under some mileage fee scenarios, increases in their overall 

transportation costs would be relatively minor because fuel taxes 

comprise a small portion of the amount that they spend on fuel. For 

example, under the scenario to maintain current conditions and 

performance, the owner of a sedan that averages 22 mpg would pay 158 

percent more in mileage fees than they pay currently in federal gasoline 

taxes. However, this represents a relatively small (7 percent) increase in 

this user’s overall transportation costs. Although cost increases under a 

change to mileage fees are greater for users of more fuel efficient 

vehicles, a hybrid owner would pay $128 less per month for the combined 
 

Page 38 GAO-13-77 Highway Trust Fund

cost of fuel and mileage fees than the owner of a less efficient SUV in the 

scenario to meet current conditions and performance, as shown in figure 

9. As such, mileage fees would not negate the economic incentives to 

drive a more fuel efficient vehicle since users would have significantly 

lower overall fuel costs.

Figure 9: Average Passenger Vehicle Users’ Monthly Fuel and Tax Costs under Current System and Mileage Fee Scenarios

Note: The “current amount paid for fuel” projection assumes a retail gasoline price of $3.75 per 

gallon, including all state and federal fuel taxes. The three mileage fee scenarios also assume an 

initial retail gasoline price of $3.75 per gallon, but then replace the 18.4 cent per-gallon federal 

gasoline tax with mileage fee costs for vehicles of varying fuel efficiency that are based on rates 

simulated using the average retail gasoline price in 2010. All scenarios assume 11,489 miles driven 

annually.

A flat-rate mileage fee for commercial trucks could also increase users’ 

costs compared with current diesel fuel taxes but would affect users 

Commercial Trucks 
 

Page 39 GAO-13-77 Highway Trust Fund

differently, in part, because larger (combination) trucks are less fuel 

efficient than smaller (single-unit) trucks. Similar to the passenger vehicle 

simulation, less fuel efficient combination trucks would pay considerably 

(35 percent) less under the scenario to replace current federal fuel tax 

receipts; more fuel efficient single-unit trucks would pay slightly (4 

percent) more than they currently pay in federal diesel taxes.68

 

68The number of miles traveled varies widely among different types of commercial trucks. 

Our projections are based on the statistics compiled using two categories of commercial 

trucks in FHWA Highway Statistics as well as fuel efficiency estimates for different types 

of single-unit and combination trucks. See National Academy of Sciences, Technologies 

and Approaches to Reducing the Fuel Consumption of Medium- and Heavy-Duty Vehicles

(Washington, D.C., 2010).

In the 

other two scenarios, single-unit truck costs would increase between 78 

percent and 176 percent, while users of combination trucks would pay 

from 11 percent to 72 percent more. However, just as combination trucks 

pay far more in diesel fuel taxes in absolute terms, they would pay more 

in mileage fees than single-unit trucks because they tend to travel 

significantly more miles annually (see fig. 10).
 

Page 40 GAO-13-77 Highway Trust Fund

Figure 10: Average Commercial Truck Users’ Annual Federal Fuel Taxes Paid under Current System Compared with Mileage 

Fee Scenarios

Note: These results assume that the federal heavy vehicle use tax and the federal tire, truck, and 

trailer excise taxes paid by commercial trucks remain in place.

Similar to passenger vehicles, drivers of commercial trucks would likely 

pay more in mileage fees than they currently pay in fuel taxes; however, 

these cost increases represent a smaller portion of their overall costs.69

 

69These projections simply apply a flat commercial truck rate to two truck types. In theory, 

heavier trucks would need to pay higher mileage fees than lighter trucks because they are 

responsible for significantly more road damage than lighter trucks.

For example, while a driver of an average combination truck would pay 72 

percent more in mileage fees than he or she currently pays in federal 

diesel taxes under the scenario to maintain current conditions and 
 

Page 41 GAO-13-77 Highway Trust Fund

performance, this represents a small (4 percent) increase in the driver’s 

monthly costs (see fig. 11).

Figure 11: Average Commercial Truck Users’ Monthly Fuel and Fuel Tax Costs under Current System and Mileage Fee 

Scenarios

Note: The “current amount paid for fuel” projection assumes a retail diesel fuel price of $4.00 per 

gallon, including all state and federal diesel fuel taxes. The mileage fee scenarios remove the 24.4-

cent federal gasoline tax and replace it with mileage fees. All scenarios assume that other federal 

taxes paid by commercial trucks remain in place.

Although mileage fees could increase costs for owners of commercial 

truck users, these users would have the ability to defray some of these 

increases by building the fees into the cost of their services. For example, 

officials from a German trucking association and a small trucking firm 

reported that the introduction of HGV tolls has not negatively affected 

trucking firms because the cost of tolls can be passed along to the 

consumers of the firm’s services. In prior work, we noted that user fees 

should be charged to the direct user, even if that payer then passes the 
 

Page 42 GAO-13-77 Highway Trust Fund

cost of the fee on to others.70 We have also noted that, to the extent that 

costs are not covered by taxes or fees levied on freight providers or 

consumers, governments would be providing a subsidy to the industry, 

which is paid by other taxpayers.71 Although mileage fees could affect the 

cost of shipping goods, they could, if set at a rate that reflects the cost of 

road use, promote economic efficiency and minimize the need for the 

federal government to subsidize transportation funding.

Although commercial trucks represent 4 percent of the U.S. vehicle fleet, 

they are responsible for 40 percent of the costs that the federal 

government spends on highway preservation and maintenance, 

according to FHWA’s Highway Cost Allocation Study, published in 2000.72

However, commercial trucks contributed less than 33 percent of Highway 

Trust Fund user fee revenues in fiscal year 2010 through federal diesel 

fuel and other truck taxes.73 We have previously reported that the current 

federal highway user fee structure is considered inequitable because it 

does not effectively capture vehicles’ weight per axle or number of miles 

traveled, the two key components of travel that cause damage.74 Heavier 

trucks generally pay less than their share of damage costs because the 

current federal tax structure does not fully account for the increased road 

wear caused by heavy trucks based on their miles traveled and weight.75

 

70

The federal diesel fuel tax—the primary source of commercial trucks’ 

GAO-08-386SP. 

71GAO, Surface Freight Transportation: A Comparison of the Costs of Road, Rail, and 

Waterways Freight Shipments That Are Not Passed on to Consumers, GAO-11-134

(Washington, D.C.: Jan. 26, 2011).

72According to FHWA, passenger vehicles represent the other 96 percent of the U.S. 

vehicle fleet and are responsible for 59.7 percent of road costs incurred. FHWA’s 2000 

addendum to its 1997 Highway Cost Allocation Study noted that this determination is 

based on federal spending patterns, and FHWA officials said that estimates that illustrate 

different vehicle types’ responsibility for highway costs irrespective of federal spending are 

not available.

73In fiscal year 2010, 67.6 percent of Highway Trust Fund user fee revenues were 

generated through the federal gasoline tax.

74GAO/RCED-94-181. 

75Conversely, individual passenger vehicles cause only very limited amounts of wear on 

the road, and the variation in wear among different light vehicles of different weights is 

also minimal.

Adjusting Mileage Fees to 

Account for the Damage 

Users Impose on 

Roadways 
 

Page 43 GAO-13-77 Highway Trust Fund

Highway Trust Fund contributions—charges all trucks the same rate of 

24.4 cents per gallon, regardless of vehicle weight or number of axles. 

Additionally, the federal heavy vehicle use tax is capped at $550 for 

trucks weighing more than 75,000 pounds, meaning that all trucks above 

this weight pay the same fee despite the increased damage costs the 

heavier trucks impose.76 In 1994, we recommended that Congress 

consider a national weight-distance user fee to increase equity and 

promote a more efficient use of the nation’s highways.77

Adjusting the illustrative mileage fee rates so that users’ contributions to 

the Highway Trust Fund reflect FHWA’s 2000 cost estimates would result 

in substantial rate increases for commercial trucks and modest decreases 

for passenger vehicles. As shown in figure 12, adjusted commercial truck 

rates would range from approximately 4 cents to 11 cents per mile, 

compared with the original range of about 3 cents to 8 cents per mile—

increases of approximately 30 percent in each scenario.

Based on 

FHWA’s 2000 estimates, commercial trucks would need to contribute 40 

percent of the revenues deposited in the Highway Trust Fund—as 

opposed to less than 33 percent in fiscal year 2010—to cover the costs 

they impose on the nation’s roadways, leaving passenger vehicles to 

contribute about 60 percent.

78

 

76Failing to charge for the additional wear caused by the heaviest trucks on the highways 

can result in a distortion of the competitive environment by making it appear that these 

trucks are a less expensive means to transport goods.

These rate 

increases are large because the increase in Highway Trust Fund 

contributions would be spread across 10 million commercial trucks, or 4 

percent of the U.S. vehicle fleet. Conversely, the adjusted passenger 

vehicle mileage fee rates would decrease modestly because the savings 

would be spread across the U.S. fleet of 230 million passenger vehicles. 

The adjusted rates account for the $2.8 billion paid in fiscal year 2010 by 

commercial trucks in federal truck taxes, which would still be needed to 

ensure that trucks contribute 40 percent of Highway Trust Fund revenues. 

Mileage fees would continue to represent a small portion of users’ overall 

transportation costs.

77GAO/RCED-94-181. 

78Converting the adjusted mileage fee rates to per-gallon charges would translate to 

significantly higher federal diesel fuel tax rates. For example, an adjusted federal diesel 

fuel tax of 45 cents per gallon would be needed under the scenario to meet current 

spending levels and a diesel fuel tax of 69.3 cents per gallon would be necessary under 

the scenario to maintain existing conditions and performance levels.
 

Page 44 GAO-13-77 Highway Trust Fund

Figure 12: Illustrative Federal Mileage Fee Rates for Three Revenue Scenarios, 

Adjusted for Cost Responsibility

Note: Our simulation produced mileage fee rates specific to three revenue targets and did not 

produce rates for any revenue amounts between the targets. As such, the lines in the figure above 

are meant to illustrate the degree of change between the rates in each of the three scenarios. The 

adjusted rates account for the $2.8 billion paid in fiscal year 2010 by commercial trucks in federal 

truck taxes, which would still be needed to ensure that trucks contribute 40 percent of Highway Trust 

Fund revenues.

Establishing user fee rates that reflect the current costs that different 

users impose on the system would require up-to-date estimates of 

vehicles’ responsibility for road damage. FHWA conducted its most recent 

full revision of its Highway Cost Allocation Study in 1997 in response to a 

GAO recommendation,79

 

79

and it issued an addendum to the study in 2000 

with updated results. However, FHWA officials reported that it is likely that 

the estimated share of commercial trucks’ responsibility for road damage 

has changed over the last 12 years because of increases in miles 

GAO/RCED-94-181. 
 

Page 45 GAO-13-77 Highway Trust Fund

traveled by heavy trucks relative to smaller trucks and cars, shifts in 

federal spending, and other factors. In addition, trucking industry 

representatives told us that an updated Highway Cost Allocation Study

would better reflect current conditions and show that commercial truck 

revenues to the Highway Trust Fund have increased in recent years 

relative to passenger vehicle revenues. This is because of improvements 

in passenger vehicles’ fuel efficiency, while commercial truck fuel 

efficiency has remained flat. Moreover, some states have been granted 

waivers to permit larger and heavier commercial trucks to travel on 

Interstate highways, which could increase the amount of damage caused 

by the vehicles. Prior GAO work has shown that designing a user fee 

system with unreliable cost information can skew fee-setting decisions.80

Furthermore, up-to-date information on the on the costs imposed by 

different users in relation to the revenues they contribute to the Highway 

Trust Fund could be used to evaluate whether the rates paid by users 

through federal motor fuel or truck taxes are sufficient. FHWA officials 

said they do not periodically update the Highway Cost Allocation Study

and have no plans to resume work on a new study at this time.

Fifty of the 51 state DOTs we surveyed agreed that it is important that an 

alternative federal funding mechanism be identified in the next 10 years in 

order to meet surface transportation revenue needs.81

 

80

However, only 8 of 

the 51 states reported that they are likely to introduce some type of 

mileage fee program in the next 10 years. Of these, 7 reported that they 

are likely to introduce mileage fees for electric vehicles in the next decade 

and fewer reported that they are likely to introduce programs for 

passenger vehicles (4) or commercial trucks (3). Although such efforts 

could produce transportation revenues for these states, they would not 

generate federal revenues for the Highway Trust Fund. However, more 

than half of all states responded that they would support federally-led field 

tests to evaluate mileage fees. There are currently no federal pilot 

programs or other efforts to evaluate the viability and cost of 

implementing such a system in the United States.

GAO-08-386SP. 

81New Jersey was the only state DOT to indicate that it does not know whether it is 

important that an alternative federal funding mechanism be identified in the next 10 years 

in order to meet surface transportation revenue needs. 

States Recognize That 

Alternative 

Transportation 

Revenues Are 

Needed, and Many 

Would Support 

Federal Actions to 

Evaluate Mileage Fee 

Systems 
 

Page 46 GAO-13-77 Highway Trust Fund

The majority of state DOTs responded that they would support federal 

field tests of mileage fees for electric vehicles and commercial trucks. 

Proponents of mileage fees have suggested that charging drivers of these 

vehicles for their road use could improve the equity and sustainability of 

Highway Trust Fund revenues:

• Electric vehicles. Two-thirds of state DOTs (34 of 51) reported they 

would support federally-led field tests of mileage fees for electric 

vehicles; none reported that they would be opposed to field tests for 

these vehicles. Electric vehicles can help achieve important policy 

goals to reduce emissions and limit U.S. dependence on foreign oil; 

however, these vehicles do not use gasoline or diesel fuel or 

contribute to the Highway Trust Fund through any other federal fees 

or taxes. The Department of Energy estimated that there were fewer 

than 60,000 electric vehicles in the United States in 2010. Although 

charging electric vehicle mileage fees would produce minimal 

revenues in the immediate future, the Department of Energy 

estimates that more than 1.2 million electric vehicles may be 

produced by 2015.82 In focus groups conducted by the Texas 

Transportation Institute, participants recognized that a potentially 

large segment of the future vehicle fleet may pay nothing aside from 

state vehicle registration and title fees for their road use and strongly 

preferred mileage fees for this class of vehicles.83 An Oregon DOT 

official reported that the state is planning to introduce legislation to 

pilot user fees for electric vehicles in 2013.

• Commercial trucks. Almost 60 percent of state DOTs (30 of 51) 

reported that they would support federally-led field tests of mileage 

fees for commercial trucks. To date, very few states have evaluated 

mileage fees for commercial trucks. In a March 2011 report to 

Congress, FHWA reported that additional technical research would be 

required to assess methods to charge heavy trucks based on their 

infrastructure wear. According to FHWA, charging trucks based on 

weight and distance traveled has been recognized as the best way to 

 

82Department of Energy, One Million Electric Vehicles by 2015: February 2011 Status 

Report (Washington, D.C., 2011).

83Texas Transportation Institute, Exploratory Study: Vehicle Mileage Fees in Texas

(College Station, Tex., January 2011). 
 

Page 47 GAO-13-77 Highway Trust Fund

reflect the road damages caused by different types of trucks.84

Although the trucking industry has resisted weight-distance taxes, 

FHWA reported that many of their objections, including administrative 

burden, can be overcome if linked with a mileage fee system. 

However, other technological issues would need to be resolved, such 

as how to measure the weight of combination vehicles that pull 

different types and numbers of trailers. FHWA reported that the 

federal government has a leadership role to play to prevent different 

systems from being established across states that later could not be

reconciled into a national mileage fee. Such a role could include field 

tests to determine how and whether a mileage fee system should be 

implemented, including at least one trial for commercial trucks, and 

the evaluation of the costs and benefits of various approaches.

While states broadly supported federal actions to explore mileage fees, 

more states placed a high priority on increasing federal fuel taxes to meet 

surface transportation revenue needs. As shown in figure 13, 23 states 

reported that they place a high level of priority on increasing federal fuel 

taxes; 21 states place a high priority on introducing a federally-led 

mileage fee. Prior GAO work has shown that a higher gasoline tax could 

encourage drivers to reduce fuel consumption by driving less, reduce the 

nation’s dependence on oil, relieve highway congestion, and decrease 

emissions of gases that pollute the air.85

 

84FHWA, Potential Research and Field Trials Related to Mileage-Based User Fees, 

Report to Congress (Washington, D.C., March 2011).

However, as vehicles become 

more fuel efficient and increasingly run on alternative fuels, fuel taxes 

may not be a long-term source of transportation funding.

85GAO, Energy Policy: Options to Reduce Environmental and Other Costs of Gasoline 

Consumption, GAO/RCED-92-260 (Washington, D.C.: Sept. 17, 1992).
 

Page 48 GAO-13-77 Highway Trust Fund

Figure 13: Number of State DOTs Reporting High Priority on Various Transportation

Funding Mechanisms, 2012

The nation’s surface transportation system is under growing strain, and 

the costs of repairs and upgrades to meet current and future demands 

are estimated in the hundreds of billions of dollars. The ongoing erosion 

of federal fuel tax revenues will worsen in the years ahead with the 

introduction and adoption of more fuel efficient and alternative fuel

vehicles. Users of the surface transportation system pay less for their use 

of roadways in federal fuel taxes and user fees than the federal 

government now spends to maintain and improve the system. The use of 

general revenues to cover Highway Trust Fund spending breaks the link 

between highway taxes paid and benefits received by users and may not 

be a sustainable strategy, given competing demands for federal funds 

and the federal government’s growing fiscal challenge.

Technologies are currently available to gather mileage data and charge 

users mileage fees, should Congress wish to explore such fees as a 

Conclusions 
 

Page 49 GAO-13-77 Highway Trust Fund

means to help address shortfalls in surface transportation funding. 

However, the perception that these technologies will be used to track 

privately-owned vehicles and infringe upon individual privacy currently 

appears to be an insurmountable challenge. Because the public 

perception of privacy risks would be particularly acute in mileage fee 

systems that mandate the use of GPS technologies, the widespread 

implementation of such a system to cover all U.S. passenger vehicles 

appears unlikely at this time. Although technology evolves rapidly and 

public perception can change over time, it may be impractical for the 

federal government to pursue mileage fees for all vehicles through a 

system that collects and reports information on people’s movements for 

the purpose of assessing taxes.

Nonetheless, there may be opportunities to evaluate mileage fees for 

certain types of vehicles that could improve the equity of highway funding 

and begin to address Highway Trust Fund shortfalls. The current U.S. fuel 

tax system does not reflect the costs of road use and the anticipated 

future changes in the U.S. vehicle fleet. Germany and New Zealand have 

demonstrated that variable rate, distance-based user fees for commercial 

trucks can generate substantial revenues linked to road damage costs 

and help reduce emissions while posing fewer privacy concerns than 

passenger vehicle systems. In the United States, commercial trucks’ 

contributions to the Highway Trust Fund through federal diesel fuel and 

related truck taxes do not reflect the relationship between truck weight 

and road damage. In addition, although few alternative fuel vehicles are 

on the roads today, their numbers are expected to increase significantly in 

the coming years, which could provide environmental and foreign policy 

benefits to the country by reducing U.S. dependence on foreign oil. 

However, drivers of these vehicles do not currently contribute to the 

Highway Trust Fund through user fees or fuel taxes for their road use. 

State DOTs reported broad support for federal initiatives to evaluate 

federal mileage fees, including federally-led field tests for electric vehicles 

and commercial trucks. State pilot programs have shown the feasibility of 

assessing mileage fees, but the programs have not shed light on how 

mileage fees could be implemented in an integrated fashion across states 

to provide revenues to the federal Highway Trust Fund. Furthermore, 

state efforts to evaluate mileage fees for commercial trucks have yet to 

determine the best approaches to address trucking industry concerns 

regarding administrative burden and compliance costs. A federal pilot 

program provides the opportunity to assess balancing those concerns 

with the goal of ensuring that federal fees cover the costs of users’ road 

use. In the absence of any current federal pilot programs or efforts to 

evaluate (1) options to more accurately charge commercial trucks and 
 

Page 50 GAO-13-77 Highway Trust Fund

electric vehicles for their road use and (2) the cost to launch and 

administer such systems, Congress lacks critical information to assess 

whether mileage fees for these vehicles could be a viable and costeffective tool to begin to address federal surface transportation funding 

challenges.

Congress and the Administration have yet to develop a long-term plan for 

funding surface transportation; ultimately, increased surface 

transportation revenues, reduced transportation spending levels, or both 

will be needed to bring revenues and spending into balance.

Consideration of new revenues—whether through mileage fees, fuel 

taxes, or other fees—would benefit from accurate and up-to-date 

information on the damage different vehicles impose on the roadways 

and whether all vehicles are currently paying their fair share. The most 

recent FHWA estimates from 2000 suggest that many commercial trucks 

underpay, but these estimates may not reflect current conditions. In the 

absence of periodically updated estimates from FHWA, Congress lacks 

the information necessary to determine whether revenues collected from 

different users are sufficient to cover the costs of their road use. Should 

Congress wish to explore mileage fees, or other sources of revenue, 

updated information would allow it to consider the costs imposed by 

different users in setting appropriate rates.

Should Congress wish to explore mileage fees as a mechanism for 

funding surface transportation, it should consider establishing a pilot 

program to evaluate the viability, costs, and benefits of mileage fee 

systems for:

• commercial trucks—to ensure that fees paid by the owners of these 

vehicles cover the costs of their use of the nation’s roads and bridges, 

and

• electric vehicles—to develop a mechanism through which the owners 

of these vehicles can contribute to the Highway Trust Fund for their 

use of the nation’s roadways.

To ensure that up-to-date data are available on the road damages 

imposed by all vehicles types compared with the revenues each 

contributes to the Highway Trust Fund, we recommend that the Secretary 

of Transportation direct the FHWA Administrator to revise and publish the 

agency’s Highway Cost Allocation Study and update it periodically as 

warranted.

Matters for 

Congressional 

Consideration 

Recommendation for 

Executive Action
 

Page 51 GAO-13-77 Highway Trust Fund

We submitted a draft of this report to the Department of Transportation for 

review and comment. The department did not take a position on our 

recommendation to revise and publish the Highway Cost Allocation Study

and update it periodically as warranted. The department provided 

technical comments via email which we incorporated as appropriate.

As agreed with your offices, unless you publicly announce the contents of 

this report earlier, we plan no further distribution until 30 days from the 

report date. At that time, we will send copies of this report to 

congressional committees with responsibilities for surface transportation 

issues and the Secretary of Transportation. In addition, this report will be 

available at no charge on GAO’s website at http://www.gao.gov.

If you or your staff have any questions about this report, please contact 

me at (202) 512-2834 or flemings@gao.gov. Contact points for our 

Offices of Congressional Relations and Public Affairs may be found on 

the last page of this report. GAO staff that made significant contributions 

to this report are listed in appendix VII.

Susan Fleming

Director, Physical Infrastructure Issues

Agency Comments
Appendix I: Objectives, Scope, and 

Methodology

Page 52 GAO-13-77 Highway Trust Fund

To assess the benefits achieved and challenges faced in mileage-based 

user fee (mileage fee) initiatives in the United States and selected other 

nations, we reviewed academic literature to identify the range of mileage 

fee pilot projects conducted in the United States and distance-based user 

fee programs introduced internationally. We interviewed the lead 

researchers and reviewed the reported results of all U.S.-based mileage 

fee pilot projects conducted as of June 2012 including: (1) a National 

Evaluation of Mileage‐based Road User Charges, conducted in 12 states 

from 2008 to 2010 by the University of Iowa, as authorized by Congress 

through the Safe, Accountable, Flexible, Efficient Transportation Equity 

Act: A Legacy for Users (SAFETEA-LU)1

; (2) the Oregon Road User Fee 

Pilot Program Oregon, conducted by the Oregon Department of 

Transportation (DOT) from 2006 to 2007; and (3) the Traffic Choices 

Study, conducted by the Puget Sound Regional Council in Washington 

state from 2005 to 2006. We also reviewed preliminary results from two 

on-going pilot projects conducted by the Minnesota DOT and Nevada 

DOT and interviewed transportation officials involved in these pilots.2

Through our literature review, we identified distance-based user fee 

initiatives in Germany, New Zealand, the Czech Republic, Switzerland, 

Austria, Slovakia, and the Netherlands. We selected three international 

programs for our review: (1) the German Heavy Goods Vehicle (HGV) 

Tolling system, which charges commercial trucks over 26,000 pounds a 

distance-based fee for travel on the national motorway, or autobahn; (2) 

the New Zealand Road User Charge (RUC) system, which charges all 

commercial trucks over 7,700 pounds and all diesel-fueled passenger 

vehicles for distances traveled on that nation’s public roadways; and (3) a 

proposed user fee initiative in the Netherlands that was suspended before 

it was implemented that would have charged all commercial trucks and 

passenger vehicles distance-based fees. We selected these programs 

using criteria that included the primary objectives of each program as 

described in the literature, the types of technology used, the classes of 

vehicles covered, and the administration of the program, such as the use 

of the private sector to implement the system. We included the 

suspended initiative in the Netherlands in our review to assess the 

challenges of implementing a national user fee program. Because we 

used a nongeneralizable sample to select the programs to review, our 

 

1

Pub. L. No. 109-59, § 1919 (a), (d), 119 Stat. 1144, 1479-1480 (2005). 

2

See appendix II for a summary of U.S.-based pilot projects as of June 2012.

Appendix I: Objectives, Scope, and 

Methodology 
Appendix I: Objectives, Scope, and 

Methodology

Page 53 GAO-13-77 Highway Trust Fund

findings are not representative of all countries with distance-based user 

fee programs. We reviewed data on the benefits achieved by these 

programs, including revenues raised, and the challenges faced in the 

programs, including their costs of implementation. We conducted a site 

visit in Berlin, Germany and interviewed government officials and private 

sector representatives from New Zealand and the Netherlands via 

teleconference.

To determine the mileage fee rates necessary to replace and supplement 

current fuel tax revenues deposited in the Highway Trust Fund and the 

effect these fees would have on users’ costs, we conducted an economic 

simulation to produce illustrative rates for passenger vehicles and 

commercial trucks, an approach that is commonly used in relevant 

existing studies. To estimate the mileage fee rates, we focused the 

hypothetical scenarios on three target levels of revenue, namely: (1) 

scenario 1, in which mileage fee revenues would simply replace federal 

gasoline and diesel fuel tax receipts deposited in the Highway Trust Fund 

($34 billion in fiscal year 2010); (2) scenario 2, in which mileage fees 

would generate revenues sufficient to meet current spending levels 

($53.5 billion in fiscal year 2010); and (3) scenario 3, in which mileage 

fees would generate the $78.4 billion necessary to maintain existing level 

of conditions and performance, assuming a 2 percent inflation rate going 

forward. In all three scenarios, we assume that the federal heavy vehicle 

use tax and the federal tire, truck and trailer excise taxes paid by 

commercial trucks ($2.8 billion in fiscal year 2010) would remain in place.

We also simulated mileage fee rates that assumed ongoing administrative 

costs of 5 percent of revenues and 20 percent of revenues. To do so, we 

increased the revenue target in scenario 1 by 5 percent ($1.7 billion) and 

20 percent ($6.8 billion) and simulated mileage fee rates using the same 

process described in this appendix and in appendix V. We then applied 

the same cost assumptions—$1.7 billion and $6.8 billion—to the revenue 

targets in scenarios 2 and 3 so that the ongoing administrative costs 

would be fixed in all scenarios and simulated mileage fee rates using the 

same process described above.

The target revenues in scenario 1 were based on fiscal year 2010 federal 

gasoline and diesel fuel tax receipts as reported in the Federal Highway 

Administration’s (FHWA) Highway Statistics 2010 report, the most current 
Appendix I: Objectives, Scope, and 

Methodology

Page 54 GAO-13-77 Highway Trust Fund

available data at the time of our review.3 In 2010, Congress directed 

$19.5 billion from the General Fund to the Highway Trust Fund and we 

used this to compute the $53.5 billion revenue target in scenario 2. For 

scenario 3, we relied on a forecast estimate by the National Surface 

Transportation Infrastructure Financing Commission (NSTIFC) report that 

$78.4 billion in federal revenues (in 2008 dollars) would be required to 

maintain the existing conditions and performance of the nation’s highway 

and transit system.4 Using NSTIFC’s assumption of a constant inflation 

rate of 2 percent, we estimated it would have required approximately 

$81.2 billion to maintain the existing conditions and performance of the 

nation’s highway and transit system in fiscal year 2010.5

To determine the respective shares of mileage fee revenues that 

passenger vehicles and commercial trucks would need to contribute, we 

looked to the amount each group contributed in federal fuel taxes in fiscal 

year 2010. First, we added the $2.8 billion that commercial trucks paid in 

the federal heavy vehicle use tax and the federal tire, and truck and trailer 

excise taxes in fiscal year 2010 to the federal diesel fuel tax revenues in 

the revenue targets to reflect the total amount of federal taxes these 

vehicles pay for their road use. Doing so temporarily increased the 

revenue targets to $36.7 billion in scenario 1, $56.2 billion in scenario 2, 

To be consistent 

with the first two scenarios, in which we excluded the $2.8 billion of 

federal heavy vehicle use tax and the federal tire, and truck and trailer 

excise taxes paid by commercial trucks in fiscal year 2010 from the 

revenue targets, we subtracted $2.8 billion from the forecast revenue 

($81.2 billion) to obtain a final target revenue of $78.4 billion.

 

3

FHWA, Highway Statistics 2010, Table FE -10 (Washington, D.C., 2012).

4

In 2010, FHWA reported that the amounts of average annual spending needed to 

maintain the conditions and performance of the nation’s surface transportation systems to 

be $101 billion for highways and $18 billion for transit. FHWA, 2010 Status of the Nation’s 

Highways, Bridges, and Transit: Conditions & Performance Report to Congress 

(Washington, D.C., 2012). The difference between these figures and our scenario 3 

revenue target is explained, in part, by: (1) the $78.4 billion target consists entirely of 

federal revenues while the $119 billion in the Condition and Performance report 

represents all levels of government and (2) both figures are average annual revenues that 

use different projected timeframes.

5

The National Surface Transportation Infrastructure Financing Commission’s 2009 report

stated that annual federal highway and transit spending requirements to maintain existing 

conditions and performance were $59 billion and $19 billion (in 2008 dollars), respectively, 

were necessary. Adjusted to reflect 2010 dollars and not including the other excise taxes 

and fees levied on commercial trucks, this is equal to $78.4 billion, per FHWA.
Appendix I: Objectives, Scope, and 

Methodology

Page 55 GAO-13-77 Highway Trust Fund

and $81.2 billion in scenario 3. Next, because the $36.7 billion deposited

in the Highway Trust Fund in 2010 was comprised of $24.8 billion (67.6 

percent) of federal gasoline tax revenues and $11.9 billion (32.4 percent) 

of federal diesel fuel tax revenues and other commercial truck taxes, we 

applied a ratio of 67.6 percent (passenger vehicles) and 32.4 percent 

(commercial trucks) to the overall revenue targets in scenarios 2 and 3. 

We then subtracted $2.8 billion from the resultant commercial truck 

figures to arrive at their revenue contribution, producing the following total 

revenue targets: $34 billion in scenario 1, $53.5 billion in scenario 2, and 

$78.4 billion in scenario 3. This final step ensured that the $2.8 billion in 

non-diesel tax revenues that commercial trucks contribute to the Highway 

Trust Fund are not considered in our simulation. Our results are intended 

to illustrate the average mileage fees that would be needed to replace 

federal fuel tax receipts and we assume that all other federal commercial 

truck taxes remain in place.

In theory, it would be possible to set mileage user fee rates to vary within 

different classes of vehicles and by location, time of day, or type of road. 

Targeted, variable mileage user fees could provide financial incentives for 

users to change their existing behavior to reduce what economists call 

externality costs, such as traffic congestion and vehicle emissions. If 

designed appropriately, finely targeted mileage fees could also maintain 

or even augment the incentive for motorists to buy more fuel efficient 

vehicles if less efficient vehicles were charged greater rates. However, as 

a result of our decision to consider only two general types of vehicles, our 

simulation model only generates two flat mileage fee rates that represent 

an average rate across each of the two vehicle types in each revenue 

scenario: one for passenger vehicles and one for commercial trucks.

To adjust our simulation’s illustrative mileage fees for passenger vehicles 

and commercial trucks to reflect the respective road damage costs they 

impose, we used the cost responsibility ratio from the 2000 update to the 

1997 Highway Cost Allocation Study compiled by FHWA to adjust each 

scenario’s revenue targets for passenger vehicles and commercial 

trucks.6

 

6

FHWA, Addendum to the 1997 Highway Cost Allocation Study Final Report, Table 4, 

(Washington, D.C., May 2000). 

FHWA’s cost responsibility ratio measures the responsibility of 

different vehicle classes for highway program costs paid from the 

Highway Trust Fund to the federal user fees paid by the different vehicle 
Appendix I: Objectives, Scope, and 

Methodology

Page 56 GAO-13-77 Highway Trust Fund

classes. To adjust the revenue targets for passenger vehicles and 

commercial trucks in each of the 3 scenarios, we first added back the 

federal tire tax, truck and trailer excise tax, and heavy vehicle use tax 

($2.8 billion in total) to the commercial truck revenue targets to reflect the 

amount of federal taxes that these vehicles pay, in total, for their road 

use. This increased the overall revenue targets to $36.7 billion in scenario 

1, $56.2 billion in scenario 2, and $81.2 billion in scenario 3. We then 

applied FHWA’s cost responsibility ratios of 59.7 percent (passenger 

vehicles) and 40.3 percent (commercial trucks) to the each scenario’s 

overall revenue target to obtain the total amount of Highway Trust Fund 

revenues that would be required from each group. This ensured that the 

amount commercial trucks paid in federal taxes in addition to federal 

diesel fuel tax revenues in fiscal year 2010 were considered as part of 

their overall contribution. We then subtracted $2.8 billion from the 

resultant figures for trucks to identify their revenue contribution through

only federal diesel fuel tax and arrive at the adjusted revenue targets. 

Adding $2.8 billion to any of the three commercial truck revenue targets 

would then result in this group’s total contribution equaling 40.3 percent of 

each scenario’s overall revenue target; each corresponding passenger 

vehicle revenue target would comprise the other 59.7 percent of each 

scenario’s overall target. We recognize that the 40.3 percent cost 

responsibility ratio is an average across all commercial truck 

configurations and weights. To more accurately charge trucks fees that 

reflect the damages they impose, variable mileage fees would need to be 

applied based on vehicle weight and number of axles.

To ensure that the key assumptions we made were reasonable, we 

calibrated the simulation using existing literature and data from 

government or other credible sources. We used data on vehicle miles 

traveled (VMT), fuel consumption, and federal gasoline and diesel tax 

receipts from FHWA Highway Statistics 2010 report, and utilized 2010

data on the average retail gasoline and diesel fuel price compiled by the 

U.S. Department of Energy’s Energy Information Agency.

Table 3 provides the key parameters used in our simulation as well as all 

passenger vehicle and commercial truck revenue targets, including those 

adjusted to reflect cost responsibility.
Appendix I: Objectives, Scope, and 

Methodology

Page 57 GAO-13-77 Highway Trust Fund

Table 3: Values of Key Parameters Used in Simulation 

Parameters Scenario Passenger vehicles Commercial Trucks Total

Average fuel efficiencya

(miles per gallon)

All 21.6 6.4 —- 

Fuel taxa

(cents per gallon)

All 18.4 24.4 —- 

Vehicle miles traveleda (VMT) 

(miles)

All 2,647,659,000,000 286,585,000,000 2,934,244,000,000

Average fuel priceb

(dollars per gallon)

All 2.84 2.99 —- 

VMT elasticity to fuel pricec All -0.40 -0.24 —- 

Revenue targetsd Scenario 1 $24,836,919,000 $9,135,819,000e $33,972,738,000

Scenario 2 $38,019,301,988 $15,453,436,012 $53,472,738,000

Scenario 3 $54,859,805,044 $23,524,195,956 $78,384,001,000

Revenue targetsf

(adjusted for cost responsibility)

Scenario 1 $21,933,742,389 $12,038,995,611 $33,972,738,000

Scenario 2 $33,575,242,389 $19,897,495,611 $53,472,738,000

Scenario 3 $48,447,266,400 $29,936,734,600 $78,384,001,000

Source: GAO analysis of FHWA data.

a

FHWA, Highway Statistics 2010, Table VM1, (Washington, D.C., 2012). We did not include VMT for 

motorcycles or buses, which are not included in the FHWA definitions of light duty vehicles, singleunit trucks, or combination trucks. In addition, buses are exempt from most highway user taxes. b

U.S. Energy Information Agency data (2010).

c

Parry, Ian and Kenneth Small, Does Britain or the United States Have the Right Gasoline Tax?, 

American Economic Review, Vol. 95. No.4, page 1283 (2005). Elasticity measures the extent VMT 

may change as a percentage in response to a one-percent increase in fuel price. For example, a VMT 

elasticity to fuel price of -0.40 means that a one percent increase in fuel price will induce a decrease 

of 0.40 in VMT.

d

FHWA, Highway Statistics 2010, Table FE10, (Washington, D.C., 2012). e

According to FHWA, illegal evasion of the diesel fuel tax might have resulted in sizeable loss of 

revenue from $1 billion to as much as 25 percent of total revenue.

f

Cost responsibility ratio from FHWA, Addendum to the 1997 Highway Cost Allocation Study, Table 4, 

(Washington, D.C., May 2000).
Appendix I: Objectives, Scope, and 

Methodology

Page 58 GAO-13-77 Highway Trust Fund

To conduct our analysis, we made a few simplifying assumptions:

1. All the light duty vehicles reported in FHWA’s Highway Statistics 2010

are passenger vehicles to facilitate comparison with FHWA’s Highway 

Cost Allocation Study;

7

2. All federal gasoline tax receipts are generated by passenger vehicles;

3. All federal diesel fuel tax receipts are generated by commercial 

trucks;8

4. If implemented, all users would pay the mileage fees (no evasion).

We anticipated the effects of these assumptions on revenues and 

mileage fee rates to be small. For example, according to the 

Environmental Protection Agency, only 0.74 percent of all model year 

2010 light duty vehicles in the United States ran on diesel fuel and, as 

result, the amount of federal diesel fuel tax receipts contributed to the 

Highway Trust Fund by passenger vehicles is minimal.9

To ensure that the simulation analysis generated reasonable results, we 

conducted a sensitivity analysis to examine how the mileage fees would 

have changed with respect to three key parameters: (1) fuel price, (2) 

VMT elasticity to fuel price, and (3) average vehicle fuel efficiency. The 

results of the analysis do not indicate any unexpected or significant 

changes in mileage fees within the examined range of parameter values.

In addition, we compared our analysis results with findings from other 

existing studies of mileage fees and found our results to be consistent 

 

7

In computing the cost responsibility ratio for all passenger vehicles, FHWA’s 2000 update 

to its 1997 Highway Cost Allocation Study included buses. However, in FHWA’s Highway 

Statistics 2010, the all light-duty vehicles category did not include buses. We decided that 

the difference is small as VMT by buses on urban and rural roads (13,789 million) was 

only 0.5 percent of that of all light-duty vehicles. See FHWA, Addendum to 1997 Highway 

Cost Allocation Study, Table 4; and FHWA, Highway Statistics 2010, Table VM-1.

8

Our model does not consider that small portions of federal gasoline fuel tax receipts are 

estimated to be derived from use in motorboats and small engines, such as lawnmowers 

and chain saws, and transferred from the Highway Trust Fund to other non-highway

accounts.

9

U.S. Environmental Protection Agency, Light-Duty Automotive Technology, Carbon 

Dioxide Emissions, and Fuel Economy Trends, 1975-2010, page viii, EPA-420R-12-001, 

(Washington, D.C., March 2012). 
Appendix I: Objectives, Scope, and 

Methodology

Page 59 GAO-13-77 Highway Trust Fund

with the existing literature.10

To examine the effect that the illustrative mileage fee rates produced by 

our simulation would have on users’ costs, we compared the annual costs 

that average drivers of passenger vehicles and commercial trucks 

currently pay in federal fuel taxes with the costs each would expect to pay 

in each of the three revenue scenarios. For passenger vehicles, we first 

divided the federal gasoline tax of 18.4 cents per gallon by varying levels

of vehicle fuel economy to establish different users’ effective mileage fee 

rates under the current system. We then multiplied each of these rates—

as well as the illustrative mileage fee rates from our simulation—by the 

average number of miles driven annually by a passenger vehicle (11,489) 

to determine the average amount different users would pay in federal fuel 

taxes under the current system or in mileage fees in the three revenue 

scenarios. In addition, we also divided the average number of miles 

driven annually by varying levels of vehicle fuel economy to determine 

how many gallons of gasoline different users would expect to purchase 

each year. We then multiplied this number by $3.57 to calculate users’ 

average fuel costs without federal taxes or mileage fees, having assumed 

a retail price of gasoline of $3.75 and subtracted the federal gasoline tax 

of 18.4 cents. To examine the effect of mileage fees for drivers of 

commercial trucks, we repeated the same steps using the federal diesel 

tax rate of 24.4 cents per gallon; the commercial truck mileage fee rates 

produced by our simulation; estimates for fuel economy and number of 

miles driven annually for single-unit trucks (8 mpg; 13,469 miles per year) 

and combination trucks (5 mpg; 68,907 miles per year) from the National 

Please refer to appendix V for a detailed 

description of the simulation analysis and its limitations.

 

10A direct comparison with the existing literature is not appropriate as these studies used 

diverse methodologies, assumptions or data. For example, our model did not account for 

external costs such as vehicle emissions and mileage fee rates that account for these 

costs would normally be higher than fees designed to only replace current revenues. As 

such, we expected our results to be at lower end of the existing estimates. For example, 

Parry and Small (2005) estimated an optimal mileage fee to account for all measurable 

external costs to be 14 cents per mile, which is significantly higher than the rates in our 

simulation. See Parry, Ian and Kenneth Small, Does Britain or the United States Have the 

Right Gasoline Tax?, American Economic Review, Vol. 95. No.4, page 1283 (2005); 

Congressional Budget Office, Alternative Approaches to Funding Highways, Pub. No. 

4090 (Washington, D.C., March 2011); FHWA, Addendum to the 1997 Highway Cost 

Allocation Study, Table 13, (Washington, D.C., May 2000); Delcan Corporation, Calmar 

Telematics, and the Greater Buffalo Niagara Regional Transportation Council, A Practical 

Approach to Truck VMT Fees, Final Report (April 2011); Parry, Ian, How Should HeavyDuty Trucks Be Taxed?, Resources for the Future Discussion Paper, RFF DP 06-23 

(Washington, D.C., 2006).
Appendix I: Objectives, Scope, and 

Methodology

Page 60 GAO-13-77 Highway Trust Fund

Academy of Sciences11

To identify states’ views on addressing future revenue demands using 

mileage fees, we surveyed the DOTs in all 50 states and the District of 

Columbia and received a 100 percent response rate. We pretested the 

survey with officials from four state departments of transportation and 

obtained feedback from FHWA officials to ensure that questions were 

clear, unbiased, comprehensive, and that terminology was used correctly. 

We made changes to the content of the questions in response to the 

pretests and FHWA review. Because we administered the survey to the 

complete universe of potential respondents, there are no sampling errors. 

However, the practical difficulties of conducting any survey may introduce 

errors, commonly referred to as non-sampling errors. For example, 

difficulties in how a particular question is interpreted, in the sources of 

information that are available to respondents, or in how the data is 

entered into a database or analyzed can introduce unwanted variability 

into the survey results. To minimize these types of errors, we employed 

recognized survey design practices in developing the questionnaire 

during pretesting and throughout the collection, processing, and analysis 

of the survey data. For example, in reviewing the survey data, we 

performed checks to identify missing or ambiguous responses and we 

addressed these errors by contacting the officials involved to clarify their 

responses. We conducted our survey from March 22 through April 24, 

2012. See Appendix VI for a summary of survey results.

 and FHWA’s Highway Statistics 2010 report; and 

an assumed retail diesel fuel price of $4.00 per gallon.

We conducted this performance audit from December 2011 through 

December 2012 in accordance with generally accepted government 

auditing standards. Those standards require that we plan and perform the 

audit to obtain sufficient, appropriate evidence to provide a reasonable 

basis for our findings and conclusions based on our audit objectives. We 

believe that the evidence obtained provides a reasonable basis for our 

findings and conclusions based on our audit objectives.

 

11National Academy of Sciences, Technologies and Approaches to Reducing the Fuel 

Consumption of Medium- and Heavy-Duty Vehicles (Washington, D.C., 2010).
Appendix II: U.S.-based Pilot Projects on 

Mileage-based User Fees

Page 61 GAO-13-77 Highway Trust Fund

Table 4: Summary of Mileage-based User Fee Pilot Projects in the United States, as of June 2012

Pilot name and location(s) Type of vehicles Summary of methodology 

National Evaluation of a 

Mileage‐based Road User Charge 

(Iowa study)

Field tests in 12 states:

California, Florida, Idaho, Illinois, 

Iowa, Kansas, Maine, Maryland,

Montana, New Mexico, North 

Carolina, and Texas

Passenger vehicles Researchers from the University of Iowa Public Policy Center tested a 

prototype mileage fee system in the vehicles of approximately 2600 

volunteer participants. The tests were conducted in two 10-month test 

phases from October 2008 through June 2010. Participants were 

surveyed before, during, and after the tests to gauge their acceptance of 

the fees.

The system used a Global Positioning System (GPS)-based, on-board 

unit that computed hypothetical mileage fees for federal, state, and, where 

applicable, local jurisdictions and periodically uploaded charges over a 

cellular communications link to a central office billing center. The billing 

center created monthly mileage charge invoices that were sent to 

participants. Officials reported that the system did not retain or transmit 

any GPS coordinates or other specific information regarding vehicle 

location or routes travelled. According to the final report, researchers 

found that mileage-based road-user charging is technically feasible using 

currently mature technologies; however, the installation of charging 

equipment into existing vehicles may pose a significant challenge.

Oregon Road User Fee Pilot 

Program 

Portland, Oregon

Passenger vehicles In April 2006, the Oregon DOT conducted a 12-month field test with 285 

volunteer vehicles, using a prototype, pay-at-the-pump mileage fee 

system. This study equipped vehicles with a GPS receiver to determine 

hypothetical mileage charges based on several zones (in-state, out-ofstate, and within the Portland metropolitan area) and a wireless 

transmitter used to transmit mileage information to the fueling station’s 

point-of-sale system at a participating gas station equipped with wireless 

receivers. When participants filled their tanks with fuel, the fueling 

station’s point of sale system sent total mileage by zone to Oregon State 

University for processing. Participants’ fuel receipts showed the difference 

in a hypothetical payment in a mileage fee system. According to the final 

report, the zone pricing strategy applied in the pilot program produced a 

22 percent decline in driving during peak periods.

Puget Sound Regional Council 

(PSRC), Traffic Choices Study

Seattle, Washington

Passenger vehicles From July 2005 through February 2006, PSRC installed GPS tolling 

meters in the vehicles of 275 volunteer households to observe driving 

patterns before and after hypothetical tolls were charged for the use of 

major freeways and arterials in the Seattle metropolitan area. The onboard unit displayed the specific toll rates applicable based on the road 

type and time-of-day. The meter stored latitude and longitude coordinates 

and toll data, and periodically transmitted it to a central office using 

cellular communications. The central office deducted hypothetical charges 

from a user account populated with funds to cover the costs of travel 

based on their typical driving habits. If participants varied their travel to 

avoid congestion charges, they would be charged a lower rate for their 

travel and could keep the balance of their accounts after the testing 

period. According to the study’s summary report, participants made smallscale adjustments in travel that, in aggregate, would have a major effect 

on transportation system performance. The study suggests there is an 

opportunity to significantly reduce traffic congestion and raise revenues 

for investment using road charging.

Appendix II: U.S.-based Pilot Projects on 

Mileage-based User Fees
Appendix II: U.S.-based Pilot Projects on 

Mileage-based User Fees

Page 62 GAO-13-77 Highway Trust Fund

Pilot name and location(s) Type of vehicles Summary of methodology 

Minnesota Department of 

Transportation Road Use Test

St. Paul, Minnesota

Passenger vehicles At the time of our review, Minnesota DOT was in the process of testing a 

mileage fee system that uses commercially-available, smart phones with 

GPS receivers and mileage-metering applications developed by 

Minnesota DOT. Minnesota DOT installed the smart-phones in a total of 

500 vehicles in three 6-month test phases. Drivers received funds from 

Minnesota DOT near the beginning of their test period based upon their 

typical driving habits and used those funds to pay monthly mileage fee 

bills sent by Minnesota DOT. The project does not collect actual revenues 

from participants as they do not pay any mileage fees that may be 

incurred in excess of the amount in their Minnesota DOT accounts. If 

participants drive fewer miles than expected, they are allowed to keep any 

remaining funds. Rates per mile vary based on location from: (a) 3-cents 

per mile inside the Minneapolis-St. Paul metropolitan area during peak, 

time-of-day travel periods; (b) 1-cent per mile during off-peak travel in the 

Minneapolis-St. Paul metropolitan area and during any time outside the 

region but in-state; and (c) no charges for out-of-state travel. Participants 

can turn off the smart phone at any time to not have their mileage 

metered. However, Minnesota DOT reads participant odometers at the 

mid-point and at the end of the study, and participants are charged 3 

cents per mile for any mileage on the odometer that was not captured on 

the smart phone system. Minnesota DOT plans to complete the tests by 

the end of 2012 and issue a final report of the results soon after.

Nevada Department of 

Transportation VMT Fee Study

Las Vegas, Nevada

Passenger vehicles At the time of our review, Nevada DOT was conducting a mini-test with 35 

vehicles using a pay-at-the pump system to prepare for a larger pilot to be 

conducted in 2013. The system to be tested does not use GPS. Instead, a 

wireless transponder is connected to vehicle’s on-board diagnostics unit 

to gather mileage data and transmit it to a wireless receiver at the fuel 

pump. The information is sent via an Internet connection to a central office 

computer, which calculates mileage fee based on the total, 

undifferentiated miles traveled. The central office sends back the 

hypothetical mileage fee which is included in the fuel receipt.

Oregon Truck Road Use 

Electronics (TRUE) Project

Oregon

Commercial trucks In 2010, Oregon DOT conducted field tests of an electronic payment 

system for Oregon’s existing weight-mile tax. Twenty-five participating 

trucks from three Oregon-based trucking firms were equipped with a 

smart phone and weight-distance tax application. Drivers input the vehicle 

weight and axle configuration at the onset of the trip into the smart phone, 

which recorded the vehicle’s mileage data. The device sent the 

information via cellular connection to Oregon DOT, which used the data to 

populate a website from which a participating motor carrier could view 

their own data only and create and transmit their monthly highway use tax 

bills to the state of Oregon. 

Source: GAO summary of pilot project documentation. 
Appendix III: User Fee Design Criteria

Page 63 GAO-13-77 Highway Trust Fund

Prior GAO work has found that the design of user fee programs can be 

evaluated based on several related criteria: efficiency, equity, revenue 

adequacy, and administrative burden.1

Table 5: GAO Criteria for User Fee Design

These criteria interact and are 

often in conflict with each other; as such, there are trade-offs to consider 

among the criteria when designing a fee (See Table 5.)

Criteria Description

Efficiency By requiring identifiable beneficiaries to pay for the costs of services, user fees can simultaneously 

constrain demand and reveal the value that beneficiaries place on the service. If those benefiting from a 

service do not bear the full social cost of the service, they may seek to have the government provide 

more of the service than is economically efficient. User fees may also foster production efficiency by 

increasing awareness of the costs of publicly-provided services, therefore increasing incentives to reduce 

costs where possible. 

Equity Equity means that everyone pays their fair share, but the definition of fair share can have multiple facets, 

in part because beneficiaries and users may not be the same. Under the beneficiary-pays principle, the 

beneficiaries of a service pay for the cost of providing the service from which they benefit. Under the 

ability-to-pay principle, those who are more capable of bearing the burden of fees should pay more for 

the service than those with less ability to pay. 

Revenue adequacy Revenue adequacy is the extent to which the fee collections cover the intended share of costs. It 

encompasses the extent to which collections may change over time relative to the cost of the program. 

For the purposes of our work, revenue adequacy also incorporates the concept of revenue stability, 

which generally refers to the degree to which short-term fluctuations in economic activity and other 

factors affect the level of fee collections. 

Administrative burden This is the cost of administering the fee, including the cost of collection and enforcement, as well as the 

compliance burden (the administrative costs imposed on the payers of the fee).

Source: GAO-08-386SP. 

 

1

GAO, Federal User Fees: A Design Guide, GAO-08-386SP (Washington, D.C.: May 29, 

2008).

Appendix III: User Fee Design Criteria
Appendix IV: The Fair Information Practices

Page 64 GAO-13-77 Highway Trust Fund

The following Fair Information Practices, with some variation, are used by 

organizations to address privacy considerations in their business 

practices and are also the basis of privacy laws and related policies in the 

United States, the European Union, and countries including Australia and 

New Zealand. These practices are not precise legal requirements. 

Rather, they provide a framework of principles for balancing the need for 

privacy with other public policy interests, such as national security, law 

enforcement, and administrative efficiency.1

Table 6: The Fair Information Practices

Principle Description

Collection limitation The collection of personal information should be limited, should be obtained by lawful and fair means, 

and, where appropriate, with the knowledge or consent of the individual.

Data quality Personal information should be relevant to the purpose for which it is collected, and should be accurate, 

complete, and current as needed for that purpose.

Purpose specification The purposes for the collection of personal information should be disclosed before collection and upon 

any change to that purpose, and its use should be limited to those purposes and compatible purposes.

Use limitation Personal information should not be disclosed or otherwise used for other than a specified purpose 

without consent of the individual or legal authority.

Security safeguards Personal information should be protected with reasonable security safeguards against risks such as loss 

or unauthorized access, destruction, use, modification, or disclosure.

Openness The public should be informed about privacy policies and practices, and individuals should have ready 

means of learning about the use of personal information.

Individual participation Individuals should have the following rights: to know about the collection of personal information, to 

access that information, to request correction, and to challenge the denial of those rights.

Accountability Individuals controlling the collection or use of personal information should be accountable for taking 

steps to ensure the implementation of these principles.

Source: Organization for Economic Cooperation and Development.

 

1

GAO, Privacy: Alternatives Exist for Enhancing Protection of Personally Identifiable 

Information, GAO-08-536 (Washington, D.C.: May 19, 2008).

Appendix IV: The Fair Information Practices
Appendix V: Mileage-based User Fee 

Simulation Model 

Page 65 GAO-13-77 Highway Trust Fund

This appendix describes the algorithm of the simulation model that we 

used to estimate mileage-based user fees (mileage fees) for various 

hypothetical scenarios with different target revenues.

The simulation model comprises four parameters and four variables (see 

table 7), and the algorithm of the simulation mainly involves repetition of 

three steps of computation until a desired target revenue is achieved. 

While the values of the parameters do not change, the variables in the 

model change from step to step. As described in appendix I, we 

calibrated the four parameters using existing literature, government data 

or other credible data sources. We then computed values of variables as 

formulated in the following equations. For expositional purpose, the 

algorithm and its steps are shown as a flow chart in figure 14.

Table 7: Description of Key Parameters and Variables Used in Simulation Analysis

Description Symbol Remark

Parameters

Vehicle miles traveled (VMT) elasticity to fuel price β Measures the extent VMT would change in response to change in 

fuel price

Fuel tax (dollars per gallon) tf Federal tax on gasoline or diesel fuel, and does not include state or 

other fuel taxes

Average fuel efficiency of vehicles (miles per gallon) FE

Per-mile fuel tax μ Measures how much the current federal fuel tax costs per mile for a 

vehicle with average fuel economy, and is, mathematically, a 

dividend of tax per gallon (i.e., fuel tax (tf)) and average miles per 

gallon (i.e. fuel economy) and can be expressed as μ= tf / FE

Variables

Mileage fee (dollars per mile) Φ

Fuel revenue (dollars) Ω Pre-determined revenue denoted as (Ω*) 

VMT (miles) VMT

Retail fuel price (dollars per gallon) P Includes federal and state fuel tax, and is the effective cost of fuel 

users pay

Source: GAO.

Step One: We first computed the mileage fee rates for passenger 

vehicles and commercial trucks using the pre-determined target revenue 

(Ω*) and VMT. For example, for the first iteration of the first scenario to 

replace the fuel tax revenue in 2010, we computed the initial mileage fee 

rates (Φ0) using gasoline and diesel tax receipts (Ω* = Ω2010) and total 

number of vehicle miles traveled in 2010 (VMT2010) as described in 

equation (1a).

Appendix V: Mileage-based User Fee 

Simulation Model

An Overview

Methodology 
Appendix V: Mileage-based User Fee 

Simulation Model

Page 66 GAO-13-77 Highway Trust Fund

Equation (1a) Φ0= Ω 2010/VMT2010; 

Next, we computed the new retail fuel price (P1). Since fuel price is 

expressed on a per gallon basis, we converted the mileage fee (Φ0) into a 

new per-gallon fuel tax (mathematically, this can be expressed as 

(Φ0*FE)). We first subtracted the existing per-gallon fuel tax (tf) from the 

2010 fuel price and added back the new per-gallon fuel tax (Φ0*FE) to get 

to the new fuel retail price. For example, using the retail fuel price for 

2010, the new retail fuel price was computed as follows:

Equation (1b) P1=[P2010 –(tf -Φ0*FE)]; 

Step Two: We used the new retail fuel price (P1) computed in step one to 

compute the number of total miles traveled (VMT1) as we assumed that 

users would respond to the fuel price change by changing the amount of 

driving. For example, using the VMT2010 for fiscal year 2010, the new 

VMT1 was derived as follows:

Equation (2) VMT1=VMT2010 *(1+β*(P1-P2010)/P2010)

Step Three: Lastly, we computed the fuel tax revenue (Ω1) by multiplying 

the new VMT1 and mileage fee (Φ0) as follows.

Equation (3) Ω1 = VMT1* Φ0;

The algorithm repeats itself by feeding the new tax revenue (Ω1) into 

equation (1a) until the final mileage fee, when multiplied by the final VMT, 

generates a pre-determined target revenue (Ω*) within a set level of 

approximation.

Equation (1a) Φ1= Ω1/VMT2010
Appendix V: Mileage-based User Fee 

Simulation Model

Page 67 GAO-13-77 Highway Trust Fund

Figure 14: Overview of the Algorithm of Computing Mileage Fees to Generate 

Predetermined Revenue

Because the simulation model focused on what mileage fee rates were 

required to generate different target revenues, we did not account for the 

following factors and conditions, which would significantly affect the 

mileage fees:

1) There were only two flat mileage fees, one for passenger vehicles and 

one for commercial trucks. We did not account for any externalities such 

as air pollution or congestion costs, nor did we model the mileage fees to 

Assumptions and 

Limitations 
Appendix V: Mileage-based User Fee 

Simulation Model

Page 68 GAO-13-77 Highway Trust Fund

vary with different types of vehicles or income levels to achieve social and 

environmental goals.

2) We assumed that vehicles fall in two broad categories marked by two 

average fuel-efficiency levels. In reality, there is substantial variation in 

fuel efficiency of vehicles within each category.

3) We assumed a uniform elasticity (i.e., response to a price change 

within each category of vehicles) even though owners of different types of 

vehicles have varying degrees of price sensitivities.

4) We assumed users only change the extent of their driving (VMT) in 

response to changes in fuel price as a result of a change in tax. In reality, 

users’ responses could also include behavior changes such as switching 

to public transit or carpooling and this would also have an effect on the 

mileage fees.

5) We did not account for factors other than fuel taxes that might affect 

VMT. These factors such as the strength of economy or higher required 

fuel economy for vehicles could significantly influence people’s driving. To 

the extent that these non- tax factors affect VMT, mileage fees for 

passenger vehicles and commercial trucks would change to meet the 

target revenues in the hypothetical scenarios.
Appendix VI: Results of GAO Survey of State 

Departments of Transportation about Mileage 

Fees

Page 69 GAO-13-77 Highway Trust Fund

To identify states’ views on addressing future revenue demands using 

mileage fees, also known as vehicle miles traveled (VMT) user fees, we 

surveyed the departments of transportation in all 50 states and the District 

of Columbia from March 22 through April 24, 2012 and received a 100 

percent response rate.

VMT User Fee Evaluation Efforts and Potential Challenges

1. Has your state DOT taken or planned to take any of the following steps 

to evaluate VMT user fees? (Check one per row.)

Question

Response

Yes 

No, but plan to 

do so in the 

next 12 months

No, and have 

no plans in the 

next 12 months Don’t Know

Total 

responses

a. Reviewed existing research 36 3 11 1 51

b. Conducted a review of the technologies 

and systems available to administer a 

VMT user fee program

16 6 27 2 51

c. Conducted economic analysis on the 

viability of a VMT system

5 5 39 2 51

d. Conducted research (e.g., survey or 

focus groups) to gauge the public’s 

potential acceptance

3 7 41 51

e. Conducted a pilot project to test a VMT 

user fee system

3 4 44 51

f. Conducted specific research to evaluate 

VMT user fees for commercial trucks

7 3 40 1 51

g. Participated in research with other 

states to evaluate VMT user fees

14 5 30 2 51

h. Shared information with other states 

related to VMT user fees

17 5 28 1 51

i. Other 6 1 6 8 21

2. Did your state legislature, governor, or transportation commission 

direct your state DOT to evaluate VMT user fees? (Check one per row.)

Question

Response

Yes No

Not applicable/

Don’t know Total responses

a. State legislature directed state DOT 8 39 3 50

b. Governor’s office directed state DOT 3 44 3 50

c. State transportation commission directed state DOT 3 43 4 50

Appendix VI: Results of GAO Survey of State 

Departments of Transportation about Mileage 

Fees
Appendix VI: Results of GAO Survey of State 

Departments of Transportation about Mileage 

Fees

Page 70 GAO-13-77 Highway Trust Fund

Question

Response

Yes No

Not applicable/

Don’t know Total responses

d. Other 7 12 6 25

3. How much of a challenge might the following issues present to 

developing a VMT user fee program in your state? (Check one per row.)

Question

Response

Very great 

challenge

Great 

challenge

Moderate 

challenge

Some 

challenge

No 

challenge

Don’t 

know

Total 

responses

a. Addressing technological issues 8 13 21 4 2 3 51

b. Addressing privacy concerns 23 22 1 2 1 2 51

c. Educating the public about the 

viability of the current gas tax to 

meet funding demands

18 9 15 7 2 51

d. Obtaining public support for a 

VMT user fee program

36 11 2 2 51

e. Obtaining support from elected 

officials for a VMT user fee 

program

30 12 6 1 2 51

f. Addressing equity concerns for 

how different groups (e.g., rural, 

urban, low-income drivers) could 

be affected

11 19 14 3 4 51

g. Administrative costs of 

implementing VMT program (e.g., 

collection of fees, enforcement, 

compliance)

14 15 13 5 4 51

h. Developing the technical 

capacity or expertise to implement 

a VMT program

7 9 26 7 2 51

i. Legal barriers to implementing a 

VMT program in state (e.g., 

required changes to state’s 

Constitution)

9 15 9 5 2 11 51

j. Obtaining funding necessary to 

evaluate or test a VMT system

9 10 17 7 2 6 51

k. Other 3 1 9 13
Appendix VI: Results of GAO Survey of State 

Departments of Transportation about Mileage 

Fees

Page 71 GAO-13-77 Highway Trust Fund

Potential Federal Actions to Develop VMT User Fee Programs

4. To what extent would your state DOT support or oppose the federal 

government taking the following actions toward the development of future 

VMT user fee systems? (Check one per row.)

Question

Response

Strongly 

support Support

Neither 

support 

nor 

oppose Oppose

Strongly 

oppose

Don’t 

know

Total 

responses

a. Establishing performance & 

interoperability standards for the 

development of VMT user fee systems

12 21 9 2 2 5 51

b. Establishing a process to certify VMT 

systems developed by the private sector

12 19 13 1 1 5 51

c. Establishing a framework for states to 

coordinate research and testing of VMT 

user fee systems

15 23 8 1 1 3 51

d. Providing Information to states on 

appropriate VMT user fee rates

9 21 13 3 2 3 51

e. Providing incentives to states to pilot or 

implement VMT user fee systems

10 21 15 2 1 2 51

f. Conducting research on the cost and 

benefits of VMT systems

13 27 7 1 3 51

g. Developing a communication plan to 

educate the public about transportation 

funding issues

19 21 6 1 3 50

h. Other 3 1 1 1 9 15

5. Would your state DOT support or oppose federally-led field tests to 

evaluate VMT user fees for the following types of vehicles? (Check one 

per row.)

Question

Response

Strongly 

support Support

Neither support 

nor oppose Oppose

Strongly 

oppose

Don’t 

know

Total 

responses

a. Passenger vehicles 5 24 16 1 5 51

b. Commercial trucks 9 21 15 1 5 51

c. Electric vehicles 9 25 13 4 51
Appendix VI: Results of GAO Survey of State 

Departments of Transportation about Mileage 

Fees

Page 72 GAO-13-77 Highway Trust Fund

6. How important or unimportant is it that the following options are 

included in future VMT field tests? (Check one per row.)

Question

Response

Very 

important Important

Neither 

important 

nor 

unimportant Unimportant

Very 

unimportant Don’t know

Total 

responses

a. Low tech options to collect 

mileage data (e.g., odometer 

readings taken during vehicle 

registration or inspections)

12 27 4 3 1 4 51

b. Systems which provide 

drivers with multiple options for 

submitting mileage data (e.g., 

on-board GPS units, odometer 

readings, self-reporting)

10 34 3 1 3 51

c. Systems with variable VMT 

fees based on vehicle fuel 

efficiency or weight

10 24 9 1 1 6 51

d. Systems with variable pricing 

elements based on time-of-day 

or congestion levels

12 17 11 4 2 5 51

e. Systems that provide users 

the option of paying fuel taxes in 

lieu of a VMT fee

8 22 12 4 1 4 51

f. Systems available through the 

marketplace (e.g., factoryinstalled devices in new 

vehicles, commercially available 

GPS units, or smartphone 

applications)

12 30 5 1 3 51

g. Evaluation of equity of VMT 

fees across different populations 

of drivers (e.g., fairness for 

rural, urban, low-income drivers)

20 20 7 1 2 50

h. Other 4 2 1 8 15
Appendix VI: Results of GAO Survey of State 

Departments of Transportation about Mileage 

Fees

Page 73 GAO-13-77 Highway Trust Fund

Identifying Additional Surface Transportation Revenue Sources

7. How important or unimportant is it that an alternative funding 

mechanism be identified by either your state or the federal government to 

meet surface transportation revenue needs in the next ten years? (Check 

one per row.)

Question

Response

Very 

important Important

Neither 

important 

nor 

unimportant Unimportant

Very 

unimportant Don’t know

Total 

responses

a. State government 32 17 2 51

b. Federal government 37 13 1 51

8. What level of priority should be placed on the following funding 

mechanisms to meet future surface transportation revenue needs? 

(Check one per row.)

Question

Response

Highest 

priority

High 

priority

Moderate 

priority

Low 

priority

Lowest 

priority Don’t know

Total 

responses

a. Increasing state fuel taxes 7 11 10 8 8 5 49

b. Introducing state-led VMT user fee 1 9 15 12 3 9 49

c. Increasing state vehicle fees (e.g., 

vehicle registration or emissions 

testing fee)

2 9 18 6 8 6 49

d. Increasing the use of tolling (e.g., 

tolls on particular facilities)

8 9 15 8 5 4 49

e. Increasing federal fuel taxes 10 13 11 5 5 5 49

f. Introducing federally-led VMT user 

fee

10 11 13 5 1 9 49

g. Other 4 1 10 15
Appendix VI: Results of GAO Survey of State 

Departments of Transportation about Mileage 

Fees

Page 74 GAO-13-77 Highway Trust Fund

9. How likely or unlikely is it that your state will introduce a VMT user fee 

program for the following types of vehicles in the next ten years? (Check 

one per row.)

Question

Response

Very likely Likely

As likely as

unlikely Unlikely

Very 

unlikely Don’t know

Total 

responses

a. Passenger vehicles 1 3 15 14 11 7 51

b. Commercial trucks 1 2 16 15 9 7 50

c. Electric vehicles 3 4 15 11 9 9 51

Additional Comments

10. What additional comments do you have on VMT user fees?

[Open-ended]

Contact Information

11. What is the name, title, telephone number, and e-mail address of the 

person who primarily completed this survey? We might contact this 

person if we have follow-up questions.

a. Name

b. Title

c. Department

d. Telephone

e. E-mail

Completion

12. Please check one of the options below. Clicking on “Completed” 

indicates that your answers are official and final.

Completed Not Completed Total responses

Your answers will not be used unless you have done this.

(Check one.)

51 51

Source: GAO.
Appendix VII: GAO Contact and Staff 

Acknowledgments

Page 75 GAO-13-77 Highway Trust Fund

Susan Fleming, (202) 512-2834 or flemings@gao.gov

In addition to the contact named above, Steve Cohen, Assistant Director; 

Matt Barranca; Richard Bulman; Colin Fallon; Bert Japikse; Terence Lam; 

Jean McSween; Faye Morrison; Josh Ormond; Namita Bhatia Sabharwal; 

and Chad Williams made key contributions to this report.

Appendix VII: GAO Contact and Staff 

Acknowledgments 

Contact 

Acknowledgments 

(541088)
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