Highway Bridge Conditions:
Issues for Congress

Robert S. Kirk
Specialist in Transportation Policy
William J. Mallett
Specialist in Transportation Policy
December 19, 2013
Congressional Research Service
7-5700
www.crs.gov
R43103


Highway Bridge Conditions: Issues for Congress

Summary
The sudden catastrophic failure of the I-5 Interstate System bridge in Washington State on May
23, 2013, has raised policy concerns in Congress regarding the condition of the nation’s
transportation infrastructure in general, and in particular the federal role in funding, building,
maintaining, and ensuring the safety of roads and especially bridges in the United States.
Of the 607,000 public road bridges, about 67,000 (11%) were classified as structurally deficient
in 2012, and another 85,000 (14%) were classified as functionally obsolete. This is less than half
the number classified as structurally deficient in 1990 and 16% less than were classified as
functionally obsolete. Structurally deficient and functionally obsolete bridges are not necessarily
unsafe. Nonetheless, public concern about bridge safety in the wake of the I-5 bridge collapse
raises the policy question of how quickly these bridges should be replaced or improved. At
current annual spending levels, the Federal Highway Administration (FHWA) estimates that the
bridge investment backlog (in dollar terms) would be reduced by 11% by 2028. Reducing the
backlog to near zero during the same period is estimated to require an annual spending rate
roughly 60% higher than recent levels.
The most recent highway bill, the Moving Ahead for Progress in the 21st Century Act (MAP-21;
P.L. 112-141), eliminated the former Highway Bridge Program, which distributed federal money
specifically for bridge improvements. States may use funds received under two major FHWA
programs, the National Highway Performance Program and the Surface Transportation Program,
for bridge repairs or construction, but the decision about how much of its funding to devote to
bridges rather than roadway needs is up to each state. FHWA enforces certain planning
requirements and performance standards established in MAP-21, but it does not make the
determination as to which bridges should benefit from federal funding.
Congressional issues regarding the nation’s highway bridge infrastructure include the following:
• Given the steady decline in the number of structurally deficient bridges during
recent decades, should Congress take action to accelerate the improvement of the
remaining deficient bridges?
• If Congress wishes to accelerate the reduction in the number of deficient bridges
under MAP-21, what can it do to encourage the states to spend more of their
federal funds on their deficient bridges?
• Given the context of large projected shortfalls in highway trust fund revenues
relative to spending, should Congress encourage increased spending on highway
bridges through increased use of tolling and public private partnerships (PPPs)?
• Should Congress consider legislation to redirect spending away from off-system
bridges to more heavily used bridges on the designated federal-aid highways?
• Congressional oversight of bridge conditions could be complicated by the
absence of a freestanding program. How quickly can FHWA develop the MAP-
21 performance measures to report to Congress on progress on bridge
conditions?
A brief CRS video on this subject may be viewed at http://www.crs.gov/video/detail.aspx?
PRODCODE=WVB00009&Source=search.
Congressional Research Service

Highway Bridge Conditions: Issues for Congress


Congressional Research Service

Highway Bridge Conditions: Issues for Congress

Contents
Background ...................................................................................................................................... 1
Bridge Conditions ...................................................................................................................... 1
Future Bridge Funding Needs ................................................................................................... 3
Federal and State Roles .................................................................................................................... 4
Bridge Inspection ....................................................................................................................... 6
FHWA’s Emergency Relief Program ......................................................................................... 7
Issues for Congress .......................................................................................................................... 7
Federal Pressure for State Bridge Spending .............................................................................. 8
Providing More Money for Bridges .......................................................................................... 8
Encourage Tolling of Nontolled Bridges ................................................................................... 9
Redirect Spending Away from Off-System Bridges .................................................................. 9
Maintenance .............................................................................................................................. 9
Oversight and Inspection Issues .............................................................................................. 10
Risk-Based Approach to Federal Bridge Oversight .......................................................... 10
Oversight of State Transportation Implementation Plans (STIPs) .................................... 10
Inspection Auditing ........................................................................................................... 10
Inspector Training and Personnel Qualifications .............................................................. 10

Figures
Figure 1. Structurally Deficient Bridges in the United States, 1990-2012 ...................................... 2

Tables
Table 1. Projected Changes in 2028 Bridge Investment Backlog Compared with 2008
Levels for Different Possible Funding Levels .............................................................................. 4
Table 2. HBP Apportionments/Obligations and Obligations from All FAHP Sources:
FY2007-2012 ................................................................................................................................ 5
Table A-1. Bridge Condition by State as of December 2012 ......................................................... 11
Table B-1. Bridge Obligations by Program ................................................................................... 13

Appendixes
Appendix A. Bridge Condition by State ........................................................................................ 11
Appendix B. Bridge Obligations by Program: FY2007-FY2012 .................................................. 13

Contacts
Author Contact Information........................................................................................................... 14
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Highway Bridge Conditions: Issues for Congress

Background
The United States has approximately 607,000 bridges on public roads subject to the National
Bridge Inspection Standards mandated by Congress.1 About 48% of these bridges are owned by
state governments and 50% by local governments. State governments generally own the larger
and more heavily traveled bridges, such as those on the Interstate Highway system. Only 1.5% of
highway bridges are owned by the federal government, primarily those on federally owned land.
About 9% of all bridges carry Interstate Highways, and another 25% serve arterial highways
other than Interstates.2 Interstate and other major arterial bridges carry almost 80% of average
daily traffic. The highest traffic loads are on Interstate Highway bridges in urban areas; these
account for only 5% of all bridges, but carried 36% of average daily traffic in 2012.3
Bridge Conditions
Federal law requires states to periodically inspect public road bridges and to report these findings
to the Federal Highway Administration (FHWA). This information permits FHWA to characterize
the existing condition of a bridge compared with one newly built and to identify those that are
structurally deficient or functionally obsolete. A bridge is considered structurally deficient “if
significant load-carrying elements are found to be in poor or worse condition due to deterioration
and/or damage, or the adequacy of the waterway opening provided by the bridge is determined to
be extremely insufficient to the point of causing intolerable traffic interruptions.”4
A functionally obsolete bridge, on the other hand, is one whose current geometric
characteristics—deck geometry (such as the number and width of lanes), roadway approach
alignment, and over/underclearances—do not meet current design standards or traffic demands. A
bridge can be both structurally deficient and functionally obsolete, but structural deficiencies take
precedence in classification. As a result, a bridge that is structurally deficient and functionally
obsolete is classified in the FHWA’s National Bridge Inventory as structurally deficient.
A bridge classified as structurally deficient or functionally obsolete is not necessarily unsafe, but
may require the posting of a vehicle weight or height restriction.
The proportion of bridges classified as structurally deficient has declined 54% since 1990, and
fell every year between 1990 and 2012 (see Figure 1). In 2012, approximately 67,000 bridges, or
11% of the total number of bridges, were classified as structurally deficient, as compared to

1 The standards, authorized at 23 U.S.C. §144, cover bridges located on public roads that are 20 feet (6.1 meters) in
length or longer. U.S. Department of Transportation, Federal Highway Administration, “Bridges by Owner, December
2012,” National Bridge Inventory, http://www.fhwa.dot.gov/bridge/britab.cfm.
2 Arterials, including Interstates, are roads designed to provide for relatively long trips at high speed and usually have
multiple lanes and limited access. U.S. Department of Transportation, Federal Highway Administration, “Functional
Classification of Bridges by Highway System, 2012 Count,” National Bridge Inventory, http://www.fhwa.dot.gov/
bridge/britab.cfm.
3 U.S. Department of Transportation, Federal Highway Administration, “Functional Classification of Bridges by
Highway System, 2012 ADT,” National Bridge Inventory, http://www.fhwa.dot.gov/bridge/britab.cfm.
4 U.S. Department of Transportation, Federal Highway Administration, and Federal Transit Administration, 2010
Status of the Nation’s Highways, Bridges, and Transit: Conditions and Performance
, Washington, DC, 3-10,
http://www.fhwa.dot.gov/policy/2010cpr/pdfs.htm.
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138,000 in 1990. The number of functionally obsolete bridges declined by 16% over the same
period.
Figure 1. Structurally Deficient Bridges in the United States, 1990-2012
Percent of All Bridges in Category
30
25
20
t
All Bridges
Rural Bridges
en 15
Perc
Urban Bridges
10
5
0
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
Source: 1990-2010: U.S. Department of Transportation, Research and Innovative Technology Administration,
Bureau of Transportation Statistics, National Transportation Statistics, table 1-28; 2011-2012: U.S. Department of
Transportation, Federal Highway Administration, National Bridge Inventory, “Count, Area, and Length of Bridges
by Highway System.”
Bridges on the most heavily traveled roads, such as Interstates and other arterials, are generally in
better condition than bridges on more lightly traveled routes. For example, 4.7% of urban
interstate bridges were considered structurally deficient in 2012, about half of the 9.8% structural
deficiency rate of urban bridges on local roads. Likewise, 4.1% of rural Interstate Highway
bridges were structurally deficient in 2012, about a quarter of the 17.2% structural deficiency rate
of bridges on rural roads handling local traffic.
As the bridges on local roads are usually owned by local governments, locally owned bridges had
more than twice the structural deficiency rate of state-owned bridges in 2012. Some 14.8% of
locally owned bridges were categorized as structurally deficient in 2012, versus 7.0% of state-
owned bridges. For bridge deficiency and obsolescence rates by state see Appendix A.
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Future Bridge Funding Needs
Every two years, FHWA assesses the condition and performance of the nation’s highways and
bridges, documents current spending by all levels of government, and estimates future spending
needs to maintain or improve current conditions and performance.5 As with any attempt to
forecast future conditions, there is a host of simplifying assumptions, omissions, and data
problems that influence the estimates of future funding needs. Among other things, the estimates
of future needs rely on forecasts of travel demands and assume that the most economically
productive projects (i.e., projects with the highest benefits relative to costs) will be implemented
first. Despite such uncertainties and assumptions, these estimates provide a way to assess the
level of current spending compared with what would be needed in the future under different
scenarios.
The 2010 needs assessment, the most recent available, shows that, in 2008, $91.1 billion was
spent on capital improvements to the nation’s highways and bridges.6 Of that amount, $76.8
billion was spent on roadways and $14.3 billion was spent on bridges. The vast majority of the
expenditure on bridges, $12.8 billion, went to rehabilitate or replace existing bridges, with the
remainder devoted to construction of new bridges.7
Because of the modeling involved, FHWA’s future needs estimates for bridges are limited to
fixing deficiencies in existing bridges only when the benefits outweigh the costs. The future
needs estimate can therefore be measured against the $12.8 billion expenditure in 2008. The U.S.
Department of Transportation (DOT) estimates that fixing all existing bridge deficiencies would
cost $121.2 billion (in 2008 dollars).8
Of course, fixing all deficient bridges overnight is not feasible. FHWA, therefore, estimates how
this investment backlog will change at various levels of spending over the 2008-2028 period,
taking into account the deterioration of existing bridges over that period. The results of this
analysis can be seen in Table 1. To keep the backlog at the 2008 level through 2028 would
require $11.9 billion annually (in 2008 dollars), less than the level of spending in 2008. To
eliminate the backlog by 2028, the maximum economically justified level of investment would be
$20.5 billion annually, implying roughly a 4% annual increase in inflation-adjusted spending.
Spending between $11.9 billion and $20.5 billion per year, FHWA estimated, would improve the
conditions of the nation’s bridges but would not entirely eliminate the investment backlog. At the
level of spending in 2008, $12.8 billion per year, the total dollar cost of correcting all remaining
deficiencies would decline by 11% by 2028.

5 The “improve” scenario is the level of spending in which the investment is made in all projects for which the
economic benefits are equal to or greater than the economic costs.
6 These spending figures do not include routine maintenance costs.
7 U.S. Department of Transportation, Conditions and Performance, 2010, exhibit 6-11.
8 U.S. Department of Transportation, Conditions and Performance, 2010, 7-27.
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Table 1. Projected Changes in 2028 Bridge Investment Backlog
Compared with 2008 Levels for Different Possible Funding Levels
Annual
Average Annual
Percentage
Spending
2028 Backlog
Percentage
Change in
(Billion 2008
(Billion 2008
Change
Spending
Dollars)
Dollars)
from 2008
Funding Level Description
4.31%
20.5
0
-100.0%
Maximum economic investment scenario
3.51% 18.7 25.3
-79.1%

2.88% 17.5 42.0
-65.3%

1.31% 14.7 79.1
-34.7%

0.56% 13.6 95.8
-20.9%

0.00%
12.8
107.6
-11.2%
2008 spending on existing bridges
-0.70% 11.9 121.2 0%
Maintain
investment
backlog
-1.00% 11.5 127.1 4.9%

Source: U.S. Department of Transportation, Federal Highway Administration and Federal Transit
Administration, 2010 Status of the Nation’s Highways, Bridges, and Transit: Conditions and Performance, exhibit 7-17.
Federal and State Roles
Federal assistance for the maintenance, rehabilitation, and construction of highway bridges comes
principally through the federal-aid highway program administered by FHWA. FHWA, however,
does not make the determination as to which bridges should benefit from federal funding. Almost
all funding under the federal-aid highway program is distributed to state departments of
transportation, which determine, for the most part, where and on what the money is spent. States
must comply with detailed federal planning guidelines as part of the decision-making process, but
otherwise are free to spend their federal highway funds in any way consistent with federal laws
and regulations. Bridge projects are developed at the state level, and state departments of
transportation let the contracts, oversee the construction process, and provide for the inspection of
bridges.9
The 2012 surface transportation reauthorization, the Moving Ahead for Progress in the 21st
Century Act (MAP-21, P.L. 112-141), further strengthened the states’ ability to determine
spending on bridges by eliminating the Highway Bridge Program (HBP), which provided money
to the states specifically for bridge construction and rehabilitation. Bridge improvements remain
eligible for funding under two programs created by MAP-21 that distribute funds to the states
under formulas specified in the law, the National Highway Performance Program (NHPP) and the
Surface Transportation Program (STP). Under both programs, the states determine how much of
their federal funding goes for bridges as opposed to other uses, primarily highway construction
and improvement. These funds may also be used for the seismic retrofitting of bridges to reduce
earthquake failure risk.10

9 See CRS Report R42793, Federal-Aid Highway Program (FAHP): In Brief, by Robert S. Kirk.
10 See CRS Report R41746, Earthquake Risk and U.S. Highway Infrastructure: Frequently Asked Questions, by
William J. Mallett, Nicole T. Carter, and Peter Folger.
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FHWA is involved in the project decision-making process in two significant ways. First, MAP-21
(§1111) requires FHWA, in consultation with the states and federal agencies, to classify public
road bridges according to “serviceability, safety, and essentiality for public use ... [and] based on
that classification, assign each a risk-based priority for systematic preventative maintenance,
replacement or rehabilitation.” However, none of the MAP-21 programs appear to require the
new classification and risk-based priority metric be used to determine program eligibility.11 In
addition to developing this metric, FHWA imposes certain performance measures that states must
meet to avoid funding penalties pursuant to MAP-21. For example, if more than 10% of the deck
area of a state’s bridges on the National Highway System is structurally deficient, the state is
subject to a penalty requiring it to dedicate an amount of its NHPP funds equal to 50% FY2009
HBP spending to bridge projects.12
While the HBP existed, bridge program apportionments—the money states were entitled to
receive each year under the HBP—were trending upward. The obligation of funds for bridge
projects, however, tended to be substantially lower than the apportioned amounts. The transfer by
the states of HBP funding to other highway programs, while permitted by law, was controversial
following the collapse of the I-35W Bridge in Minnesota in 2007. At the time, critics saw the
widening gap between annual apportionments and obligations as evidence of state transfer of
resources to nonbridge uses. However, bridge spending was an eligible expense under all the core
formula programs, not just HBP. The totals obligated from all Federal-Aid Highway programs
(FAHP) for bridge work exceeded the HBP gross apportionments for the years FY2007-FY2012.
Table 2 shows the gap between the gross apportionments and the amounts obligated under the
HBP, as well as the total obligations from all FAHP sources for FY2007 through FY2012. Past
spending on bridge improvement may provide useful benchmarks of state spending efforts during
congressional oversight.
Table 2. HBP Apportionments/Obligations and Obligations from All FAHP Sources:
FY2007-2012
Dollars in Millions

FY2007 FY2008 FY2009 FY2010 FY2011 FY2012
HBP Apportionments (gross)
$5,041 $5,058 $5,177 $5,612 $5,897 $5,509
HBP Obligations
$3,761 $4,066 $4,212 $4,284 $4,193 $3,575
Total: All Federal-Aid Highway
$6,418 $6,837 $9,386 $8,472 $7,043 $6,014
Programs’ Bridge Obligations
Source: FHWA. FY2009-FY2011 total obligations reflect obligation of stimulus funds under the American
Recovery and Reinvestment Act of 2009 (P.L. 111-5).
Note: For a detailed table of bridge obligations for these years, see Appendix B.
Under MAP-21, which eliminated the HBP, the states have even more freedom to decide how
much of their federal surface transportation grants to spend on bridges. Although there is no
freestanding bridge program under MAP-21, FHWA is able to track the obligation of federal
funds for bridge activities using bridge improvement type codes in its FMIS database.

11 Leftover funding from the Highway Bridge Program will continue to use the “sufficiency rating” for prioritizing
project eligibility. For more information see http://www.fhwa.dot.gov/bridge/bridgeload01.cfm. See also definitions of
structurally deficient and functionally obsolete at http://www.fhwa.dot.gov/bridge/0650dsup.cfm.
12 For a definition of the National Highway System see http://www.fhwa.dot.gov/planning/national_highway_system/.
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Bridge Inspection
Under the National Bridge Inspection Program (NBIP), all bridges on public roads longer than 20
feet must be inspected by state inspectors or certified inspection contractors, based on federally
defined requirements. Federal agencies are subject to the same requirements for federally owned
bridges, such as those on federal lands. Data from these inspections are reported to FHWA, which
uses them to compile a list of deficient or functionally obsolete bridges. States may use this
information to identify which bridges need replacement or repair.13
FHWA sets the standards for bridge inspection through the National Bridge Inspection Standards
(NBIS).14 The NBIS set forth how, with what frequency, and by whom bridge inspection is to be
completed. The standards provide the following:
• Each state is responsible for the inspection of all public highway bridges within
the state except for those owned by the federal government or Indian tribes.
Although the state may delegate some bridge inspection responsibilities to
smaller units of government, the responsibility for having the inspections done in
conformance with federal requirements remains with the state.
• Inspections can be done by state employees or by certified inspectors employed
by consultants under contract to a state department of transportation.
• Inspection of a federally owned bridge is the responsibility of the federal agency
that owns the bridge.
• The NBIS set forth the standards for the qualification and training of bridge
inspection personnel.
• In general, the required frequency of inspection is every 24 months. States are to
identify bridges that require less than a 24-month frequency. States can also,
however, request FHWA approval to inspect certain bridges on an up to 48-month
frequency. Frequency of underwater inspection is generally 60 months but may
be increased to 72 months with the FHWA permission.
• The most common on-site inspection is a visual inspection by trained inspectors,
one of whom must meet the additional training requirements of a team leader.
Damage and special inspections do not require the presence of a team leader.
• Load rating of a bridge must be under the responsibility of a registered
professional engineer. Structures that cannot carry maximum legal loads for the
roadway must be posted.
The vast majority of inspections are done by state employees or consultants working for the
states. FHWA inspectors do, at times, conduct audit inspections to assure that states are
complying with the bridge inspection requirements. FHWA also provides on-site engineering
expertise in the examination of the reasons for a catastrophic bridge failure. However, FHWA
bridge engineers have only limited time available for audits and other bridge oversight.

13 The National Bridge Inspection Program was initiated in 1968 following the 1967 collapse of the so-called Silver
Bridge over the Ohio River. The National Bridge Inspection Standards were first issued in 1971. See, Federal Highway
Administration, Tables of Frequently Requested NBI Information, http://www.fhwa.dot.gov/bridge/britab.cfm.
14 23 C.F.R. 650 subpart C.
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FHWA’s Emergency Relief Program
The Emergency Relief Program (ER) provides funding for bridges damaged in natural disasters
or that are subject to catastrophic failures from an outside source.15 The program provides funds
for emergency repairs immediately after the failure to restore essential traffic, as well as for
longer-term permanent repairs.
ER is authorized at $100 million per year, nationwide. Funding beyond this is commonly
provided for in supplemental appropriations acts. In the case of most large disasters, additional
ER funds are provided in an appropriations bill, usually a supplemental appropriations bill.
The federal share for emergency repairs to restore essential travel during the first 180 days
following a disaster is 100%. Later repairs, as well as permanent repairs such as reconstruction or
replacement of a collapsed bridge, are reimbursed at the same federal share that would normally
apply to the federal-aid highway facility. Recently, Congress has sometimes legislatively raised
the federal share under the ER program to 100% (as happened with the I-35W collapse in
Minnesota). As is true with other FHWA programs, the ER program is administered through state
departments of transportation in close coordination with FHWA’s division office in each state. ER
was the source of funds for replacement of the I-5 Skagit River Bridge in Washington State that
collapsed on May 23, 2013, after being struck by a truck that was hauling an oversized load.
Issues for Congress
The I-5 bridge collapse on May 23, 2013, led to warnings that the large number of structurally
deficient bridges indicates an incipient crisis,16 even though the I-5 bridge itself was not
structurally deficient.17 FHWA data do not substantiate this assertion. The numbers of bridges
classified as structurally deficient or functionally obsolete have fallen consistently since 1990,
and the proportion of all highway bridges falling into one or the other category is the lowest in
decades.
The condition of roads has not experienced the same degree of improvement as the condition of
bridges. This raises the policy question of what priority should go to bridge repairs as opposed to
roadway repairs. In MAP-21, Congress implicitly addressed this issue by giving states greater
flexibility to use federal funding for roads or for bridges, at their discretion. By doing this,
Congress chose not to mandate bridge spending levels sufficient to reduce the number of deficient

15 For a more detailed discussion of the ER program, see CRS Report R42804, Emergency Relief Program: Federal-
Aid Highway Assistance for Disaster-Damaged Roads and Bridges
, by Robert S. Kirk.
16 See, for example, the Associated Press article “Many U.S. bridges at risk of failure like Interstate 5 collapse,” Plain
Dealer
, May 26, 2013, http://www.cleveland.com/nation/index.ssf/2013/05/many_us_bridges_at_risk_of_fai.html;
“Washington bridge collapse serves as a wake-up call,” USA Today, May 28, 2013, “Bridge collapse shines light on
aging infrastructure,” USA Today, May 24, 2013, http://www.usatoday.com/story/news/nation/2013/05/24/washington-
bridge-collapse-nations-bridges-deficient/2358419/; Bryce Covert, “Washington Bridge Collapse Another Sign That
America’s Infrastructure Is In Bad Shape,” Think Progress, http://thinkprogress.org/economy/2013/05/24/2058241/
seattle-bridge-collapse-infrastructure/?mobile=nc; Angela Greiling Keane and James Nash, “I-5 Bridge Collapse
Shows Bridge Repair Needs Across U.S.,” Bloomberg, May 25, 2013, http://www.bloomberg.com/news/2013-05-24/
bridge-collapse-accents-structural-decay-as-budgets-sag.html.
17 See National Bridge Inventory: Structure Inventory and Appraisal; WA Structure: 00004794A000000, Federal
Highway Administration.
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bridges by a certain date or eliminate deficient bridges altogether (described in Table 1). Instead,
responsibility for determining the amount that should be spent on bridges each year was assigned
to the states.
A related issue is one of terminology. The terms “structurally deficient” and “functionally
obsolete” are not synonymous with “unsafe.” An effort to eliminate all structurally deficient
bridges quickly could lead to inefficient spending if a significant percentage of these bridges do
not actually have major safety problems. Under MAP-21 FHWA is to develop performance
measures in regard to bridges. The speed of their development and the effectiveness of
implementation will be oversight issues for Congress.
Federal Pressure for State Bridge Spending
To encourage state spending on structurally deficient bridges, MAP-21 sets a penalty threshold
under the NHPP: any state whose structurally deficient bridge deck area on the National Highway
System within the state’s borders exceeds 10% of its total National Highway System bridge deck
area for three years in a row must devote NHPP funds equal to 50% of the state’s FY2009
Highway Bridge program apportionment to improve bridge conditions during the following fiscal
year and each year thereafter until the deck area of structurally deficient bridges falls to 10% or
below. Even if a state were required to spend more of its federal highway funding on bridges (and
therefore less on roadway projects) due to this penalty, its mandated spending on deficient bridges
would be less than was required prior to the enactment of MAP-21.
MAP-21 expires at the end of FY2014. Given the lags in state reporting and the time required to
complete major bridge projects, it may not be clear at that point whether the states’ desire to
spend their STP or NHPP funds on nonbridge projects is obstructing the declared national policy
of reducing the number of deficient bridges. It is conceivable that Congress will begin debating
surface transportation reauthorization with limited data on the success or failure of MAP-21 in
regard to bridge improvement.
Providing More Money for Bridges
Federal motor fuel tax revenues, which have provided most of the funding for the federal-aid
highway program since 1956, have been insufficient to support the program as authorized by
Congress for several years. MAP-21 allocated money from the Treasury’s general fund for
highway and bridge programs in FY2013 and FY2014. If it wishes to increase spending on
bridges following the expiration of MAP-21, Congress has a number of options:
• Provide general fund monies to accelerate the repair of the remaining structurally
deficient and functionally obsolete bridges.
• Consider resurrecting a stand-alone program for structurally deficient bridges,
which would essentially reverse the change made in MAP-21 and would force
the states to provide minimum spending levels for bridge maintenance and repair.
• Raise the fuel taxes that finance the vast majority of surface transportation
outlays, possibly with a portion of the increase dedicated just to a federal bridge
program.
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• Emphasize public-private partnerships (PPPs) as a mechanism to help reduce the
number of structurally deficient bridges, for example, by allowing states to offer
long-term leases of toll facilities to private investors in return for large up-front
payments that could be used to supplement normal state and federal spending on
bridge replacement and repair.
Encourage Tolling of Nontolled Bridges
Heavily traveled bridges can be attractive targets for conversion to toll facilities: many bridges
have no convenient alternatives, so many drivers may be unable to avoid paying whatever toll is
imposed. Congress might consider tolling as a means of accelerating the pace of bridge repair
under the current constrained budgetary environment. An expansion of tolling could allow for
more rapid improvement of major bridges. The revenue stream provided by tolls can also make
bridge building and reconstruction an attractive investment for private entities that are interested
in participating in a PPP. The revenue stream also can help projects become eligible for a federal
Transportation Infrastructure Finance and Innovation Act (TIFIA) loan. Bridge tolls, however, are
often very unpopular, and their acceptance varies greatly from region to region. Some states have
sought to make bridge tolls more acceptable within a state by charging out-of-state users at a
much higher rate than in-state residents, a practice that may face legal challenges.
Redirect Spending Away from Off-System Bridges
Historically, nearly all federal highway funding was restricted to roads and bridges on the federal-
aid highway system. The Surface Transportation Assistance Act of 1978 (P.L. 95-599) stipulated
that not less than 15% of a state’s bridge apportionments nor more than 35% be spent “off-
system.” Off-system spending of federal bridge funds has been part of every highway
authorization bill ever since. Under MAP-21, STP funds not less than 15% of the amounts
apportioned to a state for the Highway Bridge Program in FY2009 are to be obligated for off-
system bridge projects.
Off-system bridges, by definition, are inherently local in nature. By eliminating the set-aside for
off-system bridges, Congress could enable states to spend more of their federal funds on bridges
that are more heavily used, but states would not be required to spend funds for that purpose
without additional legislation.
Maintenance
The FHWA requirement that federal funding used for bridges be directed to bridges with
relatively low sufficiency ratings may encourage states to substitute bridge replacement for
maintenance-type projects. During FY2011, of the total obligation of federal funds from all
FHWA sources, 15% was obligated for new bridges, 56% was obligated for bridge replacement,
3% was for major rehabilitation, and 24% was for minor bridge work. Although these figures
indicate that the lion’s share of bridge funding has been obligated for new and replacement
bridges, these percentages are less than they were in the late 1990s. The percentage spent on
minor bridge work has increased significantly since then.18 Still, the case can be made that as the

18 Federal Highway Administration, “Obligation of Federal Funds for Bridge Projects Underway by Improvement
Type,” Highway Statistics, Washington, FHWA, various years, and Highway Statistics 2011, Table FA-10.
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number of deficient bridges decreases, rather than reducing bridge spending it might make sense
to shift the focus on the spending over time toward preventive maintenance.
Oversight and Inspection Issues19
Risk-Based Approach to Federal Bridge Oversight
MAP-21 requires that the National Bridge Inventory classify bridges according to serviceability,
safety, and essentiality for public use and, based on this classification, assign each bridge a risk-
based priority for systematic preventative maintenance, replacement, or rehabilitation. The risk-
based approach would provide an additional metric to the traditional focus on bridges that are
“structurally deficient” and “functionally obsolete.” In particular, the risk-based approach, which
is still under development by FHWA, could provide statistics that more clearly identify unsafe
bridges. Once the metric is developed, Congress could consider making its use an eligibility
requirement for bridge project funding under NHPP and STP.
Oversight of State Transportation Implementation Plans (STIPs)
MAP-21 maintains the previous requirement that states’ spending of federal funds on bridges be
based on priorities established in state transportation implementation plans (STIPs). Following
the elimination of the Highway Bridge Program in 2012, Congress may want to examine state
spending on bridges under MAP-21 and, in particular, whether STIPs pay adequate attention to
bridge needs as opposed to highway needs.
Inspection Auditing
FHWA could be directed to take a more active role in ensuring that inspections done by the states
or their contractors are done in conformance with the National Bridge Inspection Standards,
including on-site audits of state inspections. However, to have an impact, FHWA would have to
be provided with sufficient funding to hire additional engineers and support personnel at FHWA
Division offices and dedicate these resources to oversight of the inspection program.
Inspector Training and Personnel Qualifications
MAP-21 included requirements for establishment of minimum inspection standards and an annual
review of state compliance with the standards established in the act. Within two years of
enactment the Secretary of Transportation is to update the standards for the methodology,
training, and qualifications of inspectors. Congress may wish to oversee implementation of these
provisions.

19 See also Federal Highway Administration, Tables of Frequently Requested NBI Information,
http://www.fhwa.dot.gov/bridge/britab.cfm.
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Appendix A. Bridge Condition by State
Table A-1. Bridge Condition by State as of December 2012
Percent of Bridges in State
Structurally
Functionally
All Bridges
Deficient
Obsolete
Structurally
Functionally
State
(number)
(number)
(number)
Deficient
Obsolete
Alabama 16,070
1,448
2,205
9%
14%
Alaska 1,173
128
147
11%
13%
Arizona 7,835
247
721
3%
9%
Arkansas 12,696
898
2,031
7%
16%
California 24,812
2,978
4,178
12%
17%
Colorado 8,591
566
907
7%
11%
Connecticut 4,208
406
1,070
10%
25%
Delaware 862
53
122
6%
14%
District of Columbia
239
30
155
13%
65%
Florida 11,982
262
1,764
2%
15%
Georgia 14,739
878
1,871
6%
13%
Hawai 1,131
146
359
13%
32%
Idaho 4,214
397
440
9%
10%
Illinois 26,514
2,311
1,976
9%
7%
Indiana 18,789
2,036
2,188
11%
12%
Iowa 24,496
5,193
1,282
21%
5%
Kansas 25,176
2,658
1,959
11%
8%
Kentucky 14,031
1,244
3,219
9%
23%
Louisiana 13,175
1,783
2,032
14%
15%
Maine 2,408
356
436
15%
18%
Maryland 5,294
368
1,099
7%
21%
Massachusetts 5,120 493
2,214
10%
43%
Michigan 11,000
1,354
1,672
12%
15%
Minnesota 13,121
1,190
423
9%
3%
Mississippi 17,061
2,417
1,357
14%
8%
Missouri 24,334
3,528
3,365
14%
14%
Montana 5,120
399
509
8%
10%
Nebraska 15,393
2,779
1,058
18%
7%
Nevada 1,798
40
216
2%
12%
New Hampshire
2,429
362
445
15%
18%
New Jersey
6,554
651
1,717
10%
26%
New Mexico
3,924
307
350
8%
9%
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Highway Bridge Conditions: Issues for Congress

Percent of Bridges in State
Structurally
Functionally
All Bridges
Deficient
Obsolete
Structurally
Functionally
State
(number)
(number)
(number)
Deficient
Obsolete
New York
17,420
2,169
4,718
12%
27%
North Carolina
18,165
2,192
3,296
12%
18%
North Dakota
4,453
746
247
17%
6%
Ohio 27,045
2,462
4,311
9%
16%
Oklahoma 23,781
5,382
1,604
23%
7%
Oregon 7,633
433
1,341
6%
18%
Pennsylvania 22,669
5,540
4,370
24%
19%
Rhode Island
757
156
255
21%
34%
South Carolina
9,271
1,141
840
12%
9%
South Dakota
5,870
1,208
237
21%
4%
Tennessee 19,985
1,195
2,669
6%
13%
Texas 52,260
1,372
8,680
3%
17%
Utah 2,947
126
343
4%
12%
Vermont 2,727
288
643
11%
24%
Virginia 13,769
1,250
2,421
9%
18%
Washington 7,840
366
1,693
5%
22%
West Virginia
7,093
952
1,595
13%
22%
Wisconsin 14,057
1,157
779
8%
6%
Wyoming 3,101
426
287
14%
9%
Puerto Rico
2,248
282
932
13%
41%
Total
607,380 66,749 84,748 11% 14%
(incl. Puerto Rico)
Source: U.S. Department of Transportation, Federal Highway Administration, National Bridge Inventory,
Deficient Bridges by State and Highway System, Washington, DC.

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Appendix B. Bridge Obligations by Program: FY2007-FY2012
Table B-1. Bridge Obligations by Program
FY2007-FY2012
Program FY2007
FY2008
FY2009
FY2010 FY2011 FY2012
Total,
FY2007-FY2012
Interstate Maintenance
566,367,740 531,148,044 456,257,769 659,096,900 583,304,527
755,656,556
3,020,683,491
National Highway System
629,914,133 870,072,229 597,997,506 863,300,679 836,649,803
680,253,396
3,608,115,518
Surface Transportation Program
476,908,635 547,815,377 708,246,051 603,721,498 586,685,394
558,073,243
2,933,634,820
Bridge Programs
3,761,052,215
4,066,121,536
4,211,724,679
4,283,730,495 4,193,314,245
3,575,482,507
20,025,304,142
Congestion Mitigation And Air Quality
23,905,076 52,369,318
8,579,895 47,636,428 91,470,609 (10,213,853)
161,378,157
Appalachian Development Highway System
19,971,806
449,969 61,133,266 30,653,664 28,236,759
5,436,959
145,432,455
Recreational
Trails
— — — — — —

Metropolitan
Planning
— — — — — —

1% Metropolitan Planning







High Priority Projects
141,223,886 188,500,355 226,877,040 150,934,801 224,452,978 61,045,589
804,534,295
Minimum Guarantee—TEA-21
70,261,361 (6,841,861) (5,295,640) (14,994,995) (16,498,678)
12,053,469
45,525,517
Equity Bonus Exempt Lim
55,196,232 23,363,153 96,050,658 35,326,437 14,007,551
59,268,059
259,848,937
Coordinated Border Infrastructure Program 41,711 11,580,237 23,208,473 23,039,215 30,457,277
10,461,126
87,207,802
Safe Routes To School







Planning And Research




— (200,000)
(200,000)
Al Others
673,252,684 552,598,820
3,000,825,716
1,789,136,040 470,519,916
306,635,541
6,240,369,898
Total
6,418,095,480
6,837,177,177
9,385,605,414
8,471,581,163 7,042,600,382
6,013,952,592
37,331,835,031
Source: Federal Highway Administration.

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Highway Bridge Conditions: Issues for Congress


Author Contact Information

Robert S. Kirk
William J. Mallett
Specialist in Transportation Policy
Specialist in Transportation Policy
rkirk@crs.loc.gov, 7-7769
wmallett@crs.loc.gov, 7-2216


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