United States Department of Transportation - Federal Highway AdministrationFHWA HomeFeedback

Status of the Nation's Highways, Bridges, and Transit:
2002 Conditions and Performance Report

Chapter 11: Federal Bridge Program Status of the Nation's Bridges
Skip Navigators
Index
Introduction
Highlights
Executive Summary
Part I: Description of Current System
Ch1: The Role of Highways and Transit
Ch2: System and Use Characteristics
Ch3: System Conditions
Ch4: Operational Performance
Ch5: Safety Performance
Ch6: Finance

Part II: Investment Performance Analyses
Ch7: Capital Investment Requirements
Ch8: Comparison of Spending and Investment Requirements
Ch9: Impacts of Investment
Ch10: Sensitivity Analysis

Part III: Bridges
Ch11: Federal Bridge Program Status of the Nation's Bridges

Part IV: Special Topics
Ch12: National Security
Ch13: Highway Transportation in Society
Ch14: The Importance of Public Transportation
Ch15: Macroeconomic Benefits of Highway Investment
Ch16: Pricing
Ch17: Transportation Asset Management
Ch18: Travel Model Improvement Program
Ch19: Air Quality
Ch20: Federal Safety Initiatives
Ch21: Operations Strategies
Ch22: Freight

Part V: Supplemental Analyses of System Components
Ch23: Interstate System
Ch24: National Highway System
Ch25: NHS Freight Connectors
Ch26: Highway-Rail Grade Crossings
Ch27: Transit Systems on Federal Lands

Appendices
Appendix A: Changes in Highway Investment Requirements Methodology
Appendix B: Bridge Investment/Performance Methodology
Appendix C: Transit Investment Condition and Investment Requirements Methodology
List of Contacts

Specific Bridge Types

The following areas are addressed in this section of the chapter:

  • Additional detail on Interstates, other arterials, collectors and local bridges.
  • Characterization of the superstructure material types used in the bridge network.
  • Examination of the age distribution, deficiency percentages, and deficiency trends for each superstructure material (concrete, steel, prestressed concrete, timber, and other).

Year of Construction by Functional Classification

The year of construction distribution was presented for all structures in the National Bridge Inventory. Distributions were created for Interstates (see Exhibit 11-13), other arterials (see Exhibit 11-14), collectors (see Exhibit 11-15), and local (see Exhibit 11-16) bridges. There is a distinct peak in the distribution of Interstate bridges with the average year of construction in the mid 1960's. Other functional classifications have much greater dispersion in the year of construction.

Interstate Bridges
Click here for text description of this exhibit.

Other Arterial Bridges
Click here for text description of this exhibit.

Collector Bridges
Click here for text description of this exhibit.

Local Bridges
Click here for text description of this exhibit.

Superstructure Material Types

Predominant materials used for bridge superstructures are steel, concrete, prestressed concrete, and timber. Other materials, such as aluminum, iron, and composite materials, are utilized on less than 1 percent of the structures. The percentage of superstructure materials utilized is shown in Exhibit 11-17 weighting bridges equally (by numbers), weighting by the traffic carried (ADT), and weighting by the size of the structure (by deck area). Steel bridges tend to be utilized for longer than average structures carrying higher volumes of traffic than average. Timber bridges, which constitute 5.7 percent of the inventory by numbers, carry small volumes of traffic and are smaller than average in terms of deck area. Material percentages are shown for Interstates, other arterials, collectors and local functional classifications in Exhibit 11-18.

Bridges by Type of Superstructure Material
Click here for text description of this exhibit.

Bridges by Type of Superstructure Material and Functional Class
Click here for text description of this exhibit.

The number and percentage of bridges by superstructure material, owner, and functional classification are shown in Exhibit 11-19. Figures include both rural and urban designations. Exhibit 11-20 shows the percentages of material type used for the varying functional classifications and owners for rural bridges. Exhibit 11-21 shows the same information for urban bridges.

    
Exhibit 11-19

Bridges by Type of Superstructure Material, by Owner and Functional Classification
 
FUNCTIONAL CLASS MATERIAL FEDERAL STATE LOCAL PRIVATE ALL OWNERS
Interstate
Concrete 12 (52%) 20,088 (37%) 58 (20%) 40 (10%) 20,198 (36%)
Prestressed 3 (13%) 13,288 (24%) 24 (8%) 5 (1%) 13,320 (24%)
Steel 8 (35%) 21,295 (39%) 211 (71%) 349 (89%) 21,863 (39%)
Timber 0 (0%) 6 (0%) 2 (1%) 0 (0%) 8 (0%)
Other 0 (0%) 53 (0%) 1 (0%) 0 (0%) 54 (0%)
Other Arterial
Concrete 216 (37%) 56,326 (48%) 10,088 (49%) 141 (22%) 66,782 (48%)
Prestressed 126 (22%) 25,980 (22%) 4,725 (23%) 131 (20%) 30,979 (22%)
Steel 196 (34%) 33,556 (29%) 5,076 (25%) 352 (54%) 39,249 (28%)
Timber 32 (5%) 825 (1%) 339 (2%) 11 (2%) 1,209 (1%)
Other 12 (2%) 369 (0%) 264 (1%) 12 (2%) 658 (0%)
Collector
Concrete 759 (61%) 40,496 (55%) 37,686 (45%) 64 (16%) 79,014 (50%)
Prestressed 263 (21%) 11,739 (16%) 16,735 (20%) 58 (15%) 28,836 (18%)
Steel 170 (14%) 19,763 (27%) 23,719 (29%) 224 (57%) 43,945 (28%)
Timber 27 (2%) 1,741 (2%) 4,508 (5%) 44 (11%) 6,324 (4%)
Other 19 (2%) 319 (0%) 520 (1%) 6 (2%) 867 (1%)
Local
Concrete 1,957 (26%) 8,319 (26%) 62,647 (32%) 179 (18%) 73,199 (31%)
Prestressed 1,234 (17%) 6,733 (21%) 35,537 (18%) 110 (11%) 43,651 (18%)
Steel 1,751 (24%) 15,996 (49%) 73,284 (38%) 473 (47%) 91,592 (39%)
Timber 2,452 (33%) 1,222 (4%) 22,423 (11%) 235 (23%) 26,350 (11%)
Other 56 (1%) 233 (1%) 1,529 (1%) 9 (1%) 1,829 (1%)
All Urban Bridges
Concrete 2,944 (32%) 125,229 (45%) 110,479 (37%) 424 (17%) 239,193 (41%)
Prestressed 1,626 (17%) 57,740 (21%) 57,021 (19%) 304 (12%) 116,786 (20%)
Steel 2,125 (23%) 90,610 (33%) 102,290 (34%) 1,398 (57%) 196,649 (33%)
Timber 2,511 (27%) 3,794 (1%) 27,272 (9%) 290 (12%) 33,891 (6%)
Other 87 (1%) 974 (0%) 2,314 (1%) 27 (1%) 3,408 (1%)
Source: National Bridge Inventory.

Rural Superstructure Materials by Owner and Functional Classification
Click here for text description of this exhibit.

Urban Superstructure Materials by Owner and Functional Classification
Click here for text description of this exhibit.

Exhibits 11-20 and 11-21 present the superstructure material percentages for rural and urban designations respectively. Notable differences can be seen in the Interstate bridge population with significantly higher percentages of urban Interstates constructed with steel. Prestressed superstructure bridges also constitute a higher percentage of the inventory in urban environments. Concrete (excluding prestressed concrete) is the dominant material for rural bridges. Timber superstructure bridges are prevalent in rural areas and not common in urban environments.

Concrete Superstructure Bridges (Excluding Prestressed Concrete)

The average age of concrete bridges in the NBI is approximately 40 years with an average year of construction of 1961. The average age of bridges for each combination of ownership and functional classification may be determined in Exhibit 11-22. The year of construction distribution and cumulative ADT are shown in Exhibit 11-23 for all concrete superstructure bridges (exclusive of prestressed concrete). Deficiencies and deficiency trends are shown in Exhibits 11-24 and 11-25 respectively for reinforced concrete superstructure bridges.

    
Exhibit 11-22

Average Year of Construction and Standard Deviation for Concrete Bridges by Functional Classification and Ownership
 
FUNCTIONAL CLASS AVERAGE YEAR OF CONSTRUCTION (AND STANDARD DEVIATION)
FEDERAL STATE LOCAL PRIVATE ALL OWNERS
Rural Bridges
Interstate
1964
(2)
1965
(10)
1943
(38)
1954
(9)
1965
(10)
Other Arterials
1958
(22)
1955
(21)
1971
(26)
1955
(23)
1956
(22)
Collectors
1959
(17)
1957
(20)
1962
(22)
1941
(28)
1959
(21)
Local
1960
(18)
1960
(22)
1965
(26)
1950
(36)
1964
(26)
All Rural
1960
(18)
1958
(20)
1964
(25)
1949
(32)
1961
(22)
Urban Bridges
Interstate
 
 
1966
(10)
1968
(20)
1967
(18)
1966
(10)
Other Arterials
1962
(18)
1959
(20)
1962
(23)
1943
(24)
1960
(21)
Collectors
1950
(11)
1958
(22)
1964
(25)
1935
(25)
1962
(24)
Local
1952
(19)
1964
(21)
1965
(24)
1949
(36)
1965
(24)
All Urban
1954
(18)
1961
(18)
1964
(24)
1948
(30)
1962
(21)
All Structures
1959
(18)
1958
(20)
1964
(25)
1948
(30)
1961
(22)
Source: National Bridge Inventory.

Year of Construction and Cumulative ADT - Concrete Superstructure Bridges (excluding prestressed concrete superstructures)
Click here for text description of this exhibit.

Percent Deficient - Concrete Superstructure Bridges
Click here for text description of this exhibit.

Year of Construction and Cumulative ADT - Deficient Concrete Superstructure Bridges (excluding prestressed concrete superstructures)
Click here for text description of this exhibit.

Steel Superstructure Bridges

The average age of steel bridges in the NBI is approximately 44 years with an average year of construction of 1958. The average age of bridges for all combinations of functional classification and ownership may be determined through examination of Exhibit 11-26. The year of construction distribution and cumulative ADT for all steel superstructure bridges are shown in Exhibit 11-27. Deficiencies and deficiency trends are shown in Exhibits 11-28 and 11-29 respectively for steel superstructure bridges.

    
Exhibit 11-26

Average Year of Construction and Standard Deviation for Steel Bridges by Functional Classification and Owner
 
FUNCTIONAL CLASS AVERAGE YEAR OF CONSTRUCTION (AND STANDARD DEVIATION)
FEDERAL STATE LOCAL PRIVATE AVERAGE
Rural Bridges
Interstate
1960
(10)
1967
(10)
1967
(28)
1965
(16)
1967
(10)
Other Arterials
1965
(19)
1960
(20)
1961
(29)
1951
(18)
1960
(20)
Collectors
1963
(20)
1958
(20)
1956
(23)
1945
(24)
1957
(22)
Local
1964
(21)
1963
(21)
1953
(29)
1936
(28)
1955
(28)
All Rural
1964
(21)
1961
(19)
1954
(28)
1942
(26)
1957
(25)
Urban Bridges
Interstate
1967
(8)
1969
(11)
1959
(10)
1965
(13)
1969
(11)
Other Arterials
1947
(31)
1965
(18)
1956
(25)
1947
(23)
1963
(21)
Collectors
1955
(14)
1965
(19)
1955
(25)
1949
(30)
1959
(23)
Local
1955
(20)
1967
(19)
1955
(27)
1944
(33)
1958
(25)
All Urban
1953
(23)
1967
(16)
1955
(26)
1953
(25)
1964
(20)
All Structures
1963
(21)
1963
(18)
1954
(27)
1949
(26)
1958
(24)
Source: National Bridge Inventory.

Year of Construction and Cumulative ADT - Steel Superstructure Bridges
Click here for text description of this exhibit.

Percent Deficient - Steel Superstructure Bridges
Click here for text description of this exhibit.

Year of Construction and Cumulative ADT - Deficient Steel Superstructure Bridges
Click here for text description of this exhibit.

Prestressed Concrete

Prestressed concrete was introduced in the middle of the 20th Century, and today the majority of bridges are constructed using prestressed concrete designs. The average age of prestressed concrete bridges in the NBI is approximately 24 years with an average year of construction of 1978. There are no significant differences in the age of rural versus urban prestressed bridges. The average age of bridges for all combinations of functional classification and ownership is shown in Exhibit 11-30. The year of construction distribution and cumulative ADT are shown in Exhibit 11-31 for all prestressed concrete superstructure bridges. Deficiencies and deficiency trends are shown in Exhibits 11-32 and 11-33 respectively for concrete superstructure bridges.

    
Exhibit 11-30

Average Year of Construction and Standard Deviation for Concrete Bridges by Functional Classification and Ownership
 
FUNCTIONAL CLASS AVERAGE YEAR OF CONSTRUCTION (AND STANDARD DEVIATION)
FEDERAL STATE LOCAL PRIVATE AVERAGE
Rural Bridges
Interstate
1968 (5) 1973 (10) 1996       1973 (10)
Other Arterials
1978 (12) 1980 (16) 1981 (17) 1972 (11) 1980 (16)
Collectors
1977 (11) 1978 (16) 1978 (17) 1982 (19) 1978 (16)
Local
1977 (13) 1979 (15) 1980 (17) 1981 (20) 1980 (17)
All Rural
1977 (13) 1978 (15) 1980 (17) 1979 (18) 1979 (16)
Urban Bridges
Interstate
    1975 (12) 1993 (6) 1973 (14) 1975 (12)
Other Arterials
1977 (11) 1979 (15) 1977 (18) 1979 (20) 1978 (16)
Collectors
1971 (13) 1975 (20) 1976 (19) 1982 (22) 1975 (20)
Local
1974 (19) 1978 (14) 1976 (19) 1975 (19) 1977 (18)
All Urban
1975 (17) 1977 (14) 1976 (19) 1978 (20) 1977 (16)
All Structures
1977 (13) 1978 (15) 1979 (17) 1978 (19) 1978 (16)
Source: National Bridge Inventory.

Year of Construction and Cumulative ADT - Prestressed Concrete Superstructure Bridges
Click here for text description of this exhibit.

Percent Deficient - Prestressed Concrete Superstructure Bridges
Click here for text description of this exhibit.

Year of Construction and Cumulative ADT - Deficient Prestressed Concrete Superstructure Bridges
Click here for text description of this exhibit.

Timber Bridges

Timber bridges, as described previously, are primarily used in rural environments for small spans carrying small volumes of traffic. The average age of timber bridges in the NBI is 43 years with an average year of construction of 1959. There is no significant difference between the ages of the rural and the urban timber bridge populations. The average age of timber bridges for all combinations of functional classification and ownership is presented in Exhibit 11-34. The year of construction distribution and cumulative ADT are shown in Exhibit 11-35 for all timber superstructure bridges. Deficiencies and deficiency trends are shown in Exhibits 11-36 and 11-37 respectively for timber superstructure bridges.

    
Exhibit 11-34

Average Year of Construction and Standard Deviation for Timber Bridges by Functional Classification and Ownership
 
FUNCTIONAL CLASS AVERAGE YEAR OF CONSTRUCTION (AND STANDARD DEVIATION)
FEDERAL STATE LOCAL PRIVATE ALL OWNERS
Rural Bridges
Interstate
 
 
1960
(20)
1974
(18)
 
 
1963
(20)
Other Arterials
1956
(14)
1943
(12)
1970
(30)
1956
(33)
1949
(21)
Collectors
1955
(16)
1953
(15)
1958
(21)
1933
(21)
1956
(20)
Local
1964
(18)
1960
(22)
1959
(23)
1937
(25)
1959
(23)
All Rural
1964
(18)
1953
(18)
1959
(23)
1936
(25)
1959
(22)
Urban Bridges
Interstate
 
 
 
 
 
 
 
 
 
 
Other Arterials
 
 
1946
(22)
1956
(24)
1927
(15)
1951
(24)
Collectors
1951
 
1937
(34)
1959
(30)
1919
(24)
1953
(33)
Local
1955
(19)
1951
(29)
1965
(24)
1931
(22)
1962
(25)
All Urban
1954
(18)
1945
(28)
1963
(25)
1929
(21)
1959
(27)
All Structures
1964
(18)
1953
(19)
1959
(23)
1935
(24)
1959
(23)
Source: National Bridge Inventory.

Year of Construction and Cumulative ADT - Timber Superstructure Bridges
Click here for text description of this exhibit.

Percent Deficient - Timber Superstructure Bridges
Click here for text description of this exhibit.

Year of Construction and Cumulative ADT - Deficient Timber Superstructure Bridges
Click here for text description of this exhibit.

Other Superstructure Materials

There are a small number of bridges, in terms of percentage of the population, composed of other materials, which includes aluminum, wrought and cast iron, masonry, and other uncategorized materials. The average age of these bridges is 67 years with an average year of construction of 1935. Urban bridges are, on average, older than rural bridges constructed of these other materials. The average age of these structures is shown for all combinations of functional classification and ownership in Exhibit 11-38. The year of construction distribution and cumulative ADT are shown in Exhibit 11-39 for all structures constructed of these other materials. Deficiencies and deficiency trends are shown in Exhibits 11-40 and 11-41 respectively.

    
Exhibit 11-38

Average Year of Construction and Standard Deviation for Other Superstructure Materials Bridges by Functional Classification and Ownership
 
FUNCTIONAL CLASS AVERAGE YEAR OF CONSTRUCTION (AND STANDARD DEVIATION)
FEDERAL STATE LOCAL PRIVATE AVERAGE
Rural Bridges
Interstate
 
 
1976
(9)
 
 
 
 
1976
(9)
Other Arterials
1970
(24)
1931
(37)
1912
(61)
 
 
1929
(44)
Collectors
1952
(43)
1932
(41)
1942
(39)
1927
(38)
1938
(40)
Local
1952
(34)
1952
(52)
1938
(43)
1895
(44)
1940
(44)
All Rural
1954
(36)
1939
(45)
1938
(42)
1907
(42)
1939
(43)
Urban Bridges
Interstate
 
 
1986
(16)
1979
 
 
 
1986
(16)
Other Arterials
1918
 
1929
(57)
1907
(38)
1923
(28)
1919
(50)
Collectors
 
 
1923
(45)
1923
(39)
1926
(16)
1923
(39)
Local
1942
(29)
1928
(50)
1925
(43)
1905
(33)
1926
(43)
All Urban
1940
(28)
1935
(55)
1918
(41)
1921
(27)
1924
(47)
All Structures
1952
(35)
1938
(49)
1933
(43)
1916
(32)
1935
(45)
Source: National Bridge Inventory.

Year of Construction and Cumulative ADT - Other Superstructure Materials
Click here for text description of this exhibit.

Percent Deficient - Other Superstructure Models
Click here for text description of this exhibit.

Year of Construction and Cumulative ADT - Deficient Bridges with Other Superstructure Materials
Click here for text description of this exhibit.

Culverts

In addition to examining the bridge infrastructure in terms of functional classification and ownership, it is important to examine the types of design utilized, the age of the structures, and other factors. Considering the types of design utilized, the records in the NBI describe either traditional bridge designs (80 percent— approximately 474,000 records), culverts (20 percent—approximately 117,000 records), or tunnels (104 records). The inventory is composed almost entirely of traditional bridge and culvert designs. Both of these structures provide the same purpose of providing network connectivity. However, the design and engineering properties of bridges and culverts differ dramatically. Consider the definitions of these structures as defined in the National Bridge Inspection Standards (23 CFR 650.3):

  • Bridges are defined as “supports erected over a depression or an obstruction, such as water, highway, or railway, and having a track or passageway for carrying traffic or other moving loads, and having an opening measured along the center of the roadway of more than 20 feet [6.1 meters] between undercopings of abutments or spring lines of arches.” Traditional bridges will have distinct decks, superstructures, and substructures.

  • Culverts are structures “designed hydraulically to take advantage of submergence to increase hydraulic capacity. Culverts, as distinguished from bridges, are usually covered with embankment and are composed of structural material around the entire perimeter, although some are supported on spread footings with the streambed serving as the bottom of the culvert. Culverts may qualify to be considered “bridge” length.”

For safety assurance and funding purposes, culverts and bridges are equivalent; however, since the design characteristics are significantly different, it is expected that differences in deterioration patterns will occur between the populations. Thus, it is useful to examine differences between bridge and culvert designs. The number of records describing bridge, culvert, and tunnel design is tabulated together with the traffic carried (total ADT) and the percentage of total deck area in Exhibit 11-42.

    
Exhibit 11-42

Percentage of NBI Records by Design Type
 
Design Records Total ADT Carried Total Deck Area
Bridges
80.20%
83.25%
97.90%
Culverts
19.78%
16.66%
2.05%
Tunnels
0.02%
0.09%
0.05%
Source: National Bridge Inventory.

Differences in bridge ownership and functional classification versus culvert ownership and functional classification are examined in the following figures. Examination reveals that there are only minor deviations from the overall percentages when examining alternative combinations of functional classification and ownership of bridges versus culverts. The design-type used for a particular situation is thus dependent on the conditions of the crossing and not the functional classification or jurisdictional issues.

The average age of structures in the National Bridge Inventory is approximately 40 years with an average year of construction of 1963. The age distribution of traditional bridge designs and culvert designs is examined and compared in Exhibit 11-43. Culverts tend to be younger than bridges with an average age of approximately 35 years, compared to an average age of approximately 40 years for traditional bridge designs. The average year of construction and standard deviation for traditional bridge designs and culvert designs are shown in Exhibit 11-44 and Exhibit 11-46 for all combinations of ownership and functional classification. Year of construction distributions and cumulative ADT percentages are shown in Exhibit 11-45 for traditional bridge designs and Exhibit 11-47 for culvert designs.

    
Exhibit 11-43

Bridges and Culverts by Functional Classification and Ownership
 
FUNCTIONAL CLASS OWNERSHIP
FEDERAL STATE LOCAL PRIVATE ALL
BRIDGES CULVERTS BRIDGES CULVERTS BRIDGES CULVERTS BRIDGES CULVERTS BRIDGES CULVERTS
Rural Bridges
Interstate
13
8
21,619
5,891
12
-
35
4
21,679
5,903
Other Arterials
439
85
49,777
22,066
2,029
593
137
15
52,382
22,759
Collectors
997
217
49,662
19,287
57,071
16,074
223
17
107,953
35,595
Local
6,731
563
23,892
3,841
149,968
24,726
604
25
181,195
29,155
Subtotal Rural
8,180
873
144,950
51,085
209,080
41,393
999
61
363,209
93,412
Urban Bridges
Interstate
2
 
24,966
2,238
263
20
342
13
25,573
2,271
Other Arterials
42
14
38,541
6,663
13,729
4,134
472
20
52,784
10,831
Collectors
18
6
4,580
529
7,326
2,696
151
3
12,075
3,234
Local
150
15
4,338
433
14,088
6,636
354
22
18,930
7,106
Subtotal Urban
212
35
72,425
9,863
35,406
13,486
1,319
58
109,362
23,442
Total Numbers
8,392
908
217,375
60,948
244,486
54,879
2,318
119
472,571
116,854
% of Bridges
90.24%
9.76%
78.10%
21.90%
81.67%
18.33%
95.12%
4.88%
80.17%
19.83%
% of Total ADT
85.64%
14.36%
83.98%
16.02%
77.69%
22.31%
93.17%
6.83%
83.28%
16.72%
Source: National Bridge Inventory.

    
Exhibit 11-44

Average Year of Construction for Traditional Bridge Designs by Ownership and Functional Classification
 
FUNCTIONAL CLASS AVERAGE YEAR OF CONSTRUCTION (AND STANDARD DEVIATION)
FEDERAL STATE LOCAL PRIVATE ALL OWNERS
Rural Bridges
Interstate
1963
-7
1968
-10
1959
-34
1964
-16
1968
-10
Other Arterials
1962
-20
1963
-22
1968
-29
1954
-19
1963
-23
Collectors
1964
-19
1961
-21
1962
-24
1945
-27
1961
-23
Local
1965
-19
1963
-21
1960
-28
1940
-30
1961
-27
All Rural
1964
-19
1963
-21
1961
-27
1944
-28
1962
-24
Urban Bridges
Interstate
1967
-8
1970
-11
1962
-14
1966
-14
1970
-12
Other Arterials
1959
-27
1967
-20
1961
-26
1953
-27
1965
-22
Collectors
1959
-14
1964
-22
1961
-26
1952
-32
1962
-25
Local
1958
-22
1968
-20
1961
-27
1946
-33
1962
-26
All Urban
1959
-23
1968
-18
1961
-26
1954
-28
1965
-22
All Structures
1964
-19
1964
-20
1961
-27
1950
-28
1962
-24
Source: National Bridge Inventory.

Year of Construction and Cumulative ADT for Traditional Bridge Designs
Click here for text description of this exhibit.

    
Exhibit 11-46

Average Year of Construction for Culverts by Ownership & Functional Classification
 
FUNCTIONAL CLASS AVERAGE YEAR OF CONSTRUCTION (AND STANDARD DEVIATION)
FEDERAL STATE LOCAL PRIVATE  AVERAGE
Rural Bridges
Interstate
1964 -2 1965 -11 1956 -12 1965 -11
Other Arterials
1980 -15 1957 -22 1977 -20 1972 -22 1958 -22
Collectors
1961 -17 1959 -19 1967 -20 1956 -30 1963 -20
Local
1969 -19 1977 -18 1974 -22 1975 -24 1974 -22
All Rural
1968 -19 1961 -20 1971 -22 1968 -26 1965 -21
Urban Bridges
Interstate
1967 -11 1984 -18 1958 -9 1967 -11
Other Arterials
1962 -20 1965 -20 1970 -19 1948 -30 1967 -20
Collectors
1947 -13 1971 -20 1972 -20 1959 -45 1972 -20
Local
1949 -17 1977 -20 1973 -19 1989 -20 1973 -19
All Urban
1954 -18 1966 -19 1972 -19 1966 -29 1970 -19
All Structures
1968 -19 1961 -20 1971 -21 1967 -27 1966 -21
Source: National Bridge Inventory.

Conclusion

Bridges, as critical components of the highway system, must be maintained and preserved to ensure safety to the traveling public, support commerce and mobility within the Nation, and retain the significant accumulated asset value of the inventory. The Nation's bridges and culverts are aging and traffic demands are increasing. At the same time, funds for capital construction are becoming scarcer. Asset management principles through management systems and transportation system preservation techniques are becoming more important as the States, locals and the Federal Government struggle to maintain the safe condition of the Nation's bridges and culverts, while at the same time providing for increased demands on the highway network. Improved bridge and culvert inspection techniques, through the use of new and innovative equipment, are needed to better insure the safety of the motoring public. Longer design life structures, using the latest material and design technologies, are needed so that the Nation can maintain a functional transportation network, provide longer service life, and improve the safety of the highway network. Emphasis is needed on research so that we can continually improve the condition of the Nation's bridges and culverts.


   Back
Up to Navigation Bar
Forward   

FHWA Home | Feedback
FHWA