FOREWORD

The Recording and Coding Guide for the Structure Inventory and Appraisal 

of the Nation's Bridges (Guide) has been revised several times in the 

past. This latest edition revises the Guide to convert all of the units 

of measurement to the International System of Units. This revised Guide 

represents several years of effort by the Federal Highway Administration 

with the States' cooperation and comments, both indvidually and through 

the AASHTO Subcommittee on Bridges and Structures.

Initial distribution of the Guide is being made directly to each FHWA 

field office for distribution to the States. Additional copies are 

available from the Bridge Management Branch (HNG-33) of the FHWA Bridge 

Division.

William A. Weseman, Director

Office of Engineering

Under the Paper Work Reduction Act and CFR 1320 the

Structure Inventory and Appraisal Sheet reporting

requirements have been cleared by OMB under 2125-0501.
RECORDING AND CODING GUIDE

FOR THE STRUCTURE INVENTORY AND APPRAISAL OF THE NATION'S BRIDGES

_________________________________________________________________

Report No. FHWA-PD-96-001

Prepared by

Office of Engineering

Bridge Division

Bridge Management Branch

Washington, D.C. 20590

December 1995 
TABLE OF CONTENTS

 Page

INTRODUCTION vi

DEFINITION OF TERMS viii

DATA ITEMS

 1 State Code 1

 2 Highway Agency District 1

 3 County (Parish) Code 1

 4 Place Code 2

 5 Inventory Route 2

 6 Features Intersected 5

 7 Facility Carried by Structure 5

 8 Structure Number 6

 9 Location 6

 10 Inventory Route, Minimum Vertical Clearance 6

 11 Kilometer Point 7

 12 Base Highway Network 7

 13 LRS Inventory Route, Subroute Number 8

 14 (Reserved) 8

 15 (Reserved) 8

 16 Latitude 8

 17 Longitude 9

 18 (Reserved) 9

 19 Bypass, Detour Length 10

 20 Toll 11

 21 Maintenance Responsibility 12

 22 Owner 12

 23 (Reserved) 12

 24 (Reserved) 12

 25 (Reserved) 12

 26 Functional Classification of Inventory Route 13

 27 Year Built 13

 28 Lanes On and Under the Structure 14

 29 Average Daily Traffic 15

 30 Year of Average Daily Traffic 16

 31 Design Load 16

 32 Approach Roadway Width 16

 33 Bridge Median 18

 34 Skew 19

 35 Structure Flared 19

 36 Traffic Safety Features 19

 37 Historical Significance 21

 38 Navigation Control 21

 39 Navigation Vertical Clearance 22

 40 Navigation Horizontal Clearance 22

 41 Structure Open, Posted, or Closed to Traffic 22

 42 Type of Service 23

 43 Structure Type, Main 24

 44 Structure Type, Approach Spans 25

iii
Item Page

 45 Number of Spans in Main Unit 26

 46 Number of Approach Spans 26

 47 Inventory Route, Total Horizontal Clearance 26

 48 Length of Maximum Span 28

 49 Structure Length 28

 50 Curb or Sidewalk Widths 30

 51 Bridge Roadway Width, Curb-to-Curb 32

 52 Deck Width, Out-to-Out 33

 53 Minimum Vertical Clearance Over Bridge Roadway 33

 54 Minimum Vertical Underclearance 33

 55 Minimum Lateral Underclearance on Right 35

 56 Minimum Lateral Underclearance on Left 37

 57 (Reserved) 37

-- Condition Ratings 37

 58 Deck 38

 59 Superstructure 39

 60 Substructure 39

 61 Channel and Channel Protection 40

 62 Culverts 41

 63 Method Used to Determine Operating Rating 42

 64 Operating Rating 43

 65 Method Used to Determine Inventory Rating 44

 66 Inventory Rating 44

-- Appraisal Ratings 45

 67 Structural Evaluation 46

 68 Deck Geometry 48

 69 Underclearances, Vertical and Horizontal 52

 70 Bridge Posting 55

 71 Waterway Adequacy 56

 72 Approach Roadway Alignment 57

 73 (Reserved) 58

 74 (Reserved) 58

 75 Type of Work 58

 76 Length of Structure Improvement 60

 77 (Reserved) 62

 78 (Reserved) 62

 79 (Reserved) 62

 80 (Reserved) 62

 81 (Reserved) 62

 82 (Reserved) 62

 83 (Reserved) 62

 84 (Reserved) 62

 85 (Reserved) 62

 86 (Reserved) 62

 87 (Reserved) 62

 88 (Reserved) 62

 89 (Reserved) 62

 90 Inspection Date 62

 91 Designated Inspection Frequency 62

iv
Item Page

 92 Critical Feature Inspection 63

 93 Critical Feature Inspection Date 64

 94 Bridge Improvement Cost 64

 95 Roadway Improvement Cost 65

 96 Total Project Cost 65

 97 Year of Improvement Cost Estimate 66

 98 Border Bridge 66

 99 Border Bridge Structure Number 66

100 STRAHNET Highway Designation 67

101 Parallel Structure Designation 67

102 Direction of Traffic 68

103 Temporary Structure Designation 68

104 Highway System of the Inventory Route 69

105 Federal Lands Highways 69

106 Year Reconstructed 69

107 Deck Structure Type 70

108 Wearing Surface/Protective System 70

109 Average Daily Truck Traffic 71

110 Designated National Network 72

111 Pier or Abutment Protection (for Navigation) 72

112 NBIS Bridge Length 73

113 Scour Critical Bridges 75

114 Future Average Daily Traffic 77

115 Year of Future Average Daily Traffic 77

116 Minimum Navigation Vertical Clearance 77

 Vertical Lift Bridge 

GENERAL 78

APPENDIX A Structure Inventory and Appraisal Sheet

APPENDIX B Sufficiency Rating Formula and Example

APPENDIX C National Bridge Inspection Standards

APPENDIX D Commentary

APPENDIX E NBI Record Format

v
INTRODUCTION

The Recording and Coding Guide for the Structure Inventory and Appraisal 

of the Nation's Bridges, hereafter referred to as the Guide, has been 

revised several times in the past. This latest edition revises the 

Guide to convert all of the units of measurement to the International 

System of Units (SI). It also provides more thorough and detailed 

guidance in evaluating and coding specific bridge data. New items have 

been added to include the reporting of Federal Lands Highway Systems, 

each State's existing linear referencing system (LRS), and the method 

used to determine the load ratings. Some items in the Guide have also 

been expanded to provide more definitive and explicit explanations and 

instructions for coding. Further, more basic definitions applicable to 

the instructions in the Guide are provided. The changes are based on 

comments received on the previous Guide and the metric version (January 

1994) draft Guide. This revised Guide should be thoroughly reviewed by 

each individual involved with the National Bridge Inspection Program.

This Guide has been prepared for use by the States, Federal and other 

agencies in recording and coding the data elements that will comprise 

the National Bridge Inventory data base. By having a complete and 

thorough inventory, an accurate report can be made to the Congress on 

the number and state of the Nation's bridges. The Guide also provides 

the data necessary for the Federal Highway Administration (FHWA) and the 

Military Traffic Management Command to identify and classify the 

Strategic Highway Corridor Network and it's connectors for defense 

purposes.

The coded items in this Guide are considered to be an integral part of 

the data base that can be used to meet several Federal reporting 

requirements, as well as part of the States' needs. These requirements 

are set forth in the National Bridge Inspection Standards (23 CFR 650.3) 

which are included as Appendix C. A complete, thorough, accurate, and 

compatible data base is the foundation of an effective bridge management 

system. Reports submitted in connection with the Highway Bridge 

Replacement and Rehabilitation Program and the National Bridge 

Inspection Program also are related to this Guide.

The AASHTO Manual for Condition Evaluation of Bridges discusses the 

various items of information that are to be recorded as part of original 

bridge reports. That manual and the Bridge Inspector's Training 

Manual/90, with supplements, discuss inspection procedures and the 

preparation of detailed reports about the structure components. These 

reports will be the basis for recording values for many of the data 

elements shown in the Guide, particularly those having to do with the 

condition or the appraisal ratings.

Some bridge owners are collecting bridge condition ratings for items 

included in this Guide (Items 58-Deck, 59-Superstructure, 60-

Substructure, and 62-Culvere) using the American Association of 

 vi 

2000
Highway and Transportation Officials' (AASHTO) Guide for Commonly 

Recognized (CoRe) Structural Elements. CoRe element inspection ratings 

provide detailed condition assessments that can serve as input

into a comprehensive bridge management system (BMS). The FHWA has 

provided bridge owners with a computer program for translating bridge 

condition data in the CoRe element format to National Bridge Inventory 

(NBI) condition ratings for the purpose of NBI data submittal to FHWA. 

The purpose of the program is to permit bridge inspectors to record 

condition information in a format that satisfies both BMS and NBI data 

collection requirements.

The Structure Inventory and Appraisal (SI&A) Sheet and the sufficiency 

rating formula, with examples, are included as Appendices A and B, 

respectively. The SI&A sheet is intended to be a tabulation of the 

pertinent elements of information about an individual structure. Its 

use is optional, subject to the statements in the preceding paragraph of 

this Introduction. It is important to note that the SI&A Sheet is not 

an inspection form but merely a summary sheet of bridge data required by 

the FHWA to effectively monitor and manage a National bridge program.

States, Federal and other agencies are encouraged to use the codes and 

instructions in this Guide. However, its direct use is optional; each 

agency may use its own code scheme provided that the data are directly 

translatable into the Guide format. When data are requested by FHWA, 

the format will be based on the codes and instructions in this Guide. 

An agency choosing to use its own codes shall provide for translation or 

conversion of its own codes into those used in the Guide. In other 

words, agencies are responsible for having the capability to obtain, 

store, and report certain information about bridges whether or not this 

Guide or the SI&A Sheet is used. Any requests by the FHWA for 

submittals of these data will be based on the definitions, explanations, 

and codes supplied in the Guide, the AASHTO Manual for Condition 

Evaluation of Bridges and the Bridge Inspector's Training Manual/90 plus 

supplements.

The values provided in the tables or otherwise listed in this Guide are 

for rating purposes only. Current design standards must be used for 

structure design or rehabilitation. All possible combinations of actual 

site characteristics are not provided in this Guide. If a special 

situation not listed in the Guide is encountered, the evaluation 

criteria closest to the actual site situation should be used.

The implementation of this Guide may require some restructuring of an 

agency's data base and support software. If so, it is suggested that 

the agency consider the additional enhancements that would be necessary 

to support a bridge management system.

Appendix D is a Commentary that compares, item by item, the 1988 Guide 

to this Guide. The Commentary will provide a ready reference for item 

changes.

vii 

 

2000
DEFINITION OF TERMS

The definitions of terms used in the Guide are provided below.

(1) Bridge. The National Bridge Inspection Standards published in the 

Code of Federal Regulations (23 CFR 650.3) give the following 

definition:

A structure including 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* between undercopings of abutments or spring lines of 

arches, or extreme ends of openings for multiple boxes; it may also 

include multiple pipes, where the clear distance between openings 

is less than half of the smaller contiguous opening.

 * (6.1 meters)

(b) Culvert. A structure 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. 

(c) Inventory Route. The route for which the applicable inventory data 

is to be recorded. The inventory route may be on the structure or 

under the structure. Generally inventories along a route are made 

from west to east and south to north.

(d) National Bridge Inventory (NBI). The aggregation of structure 

inventory and appraisal data collected to fulfill the requirements 

of the National Bridge Inspection Standards. Each State shall 

prepare and maintain an inventory of all bridges subject to the 

NBIS.

(e) National Bridge Inventory (NBI) Record. Data which has been coded 

according to the Guide for each structure carrying highway traffic 

or each inventory route which goes under a structure. These data 

are furnished and stored in a compact alphanumeric format on 

magnetic tapes or disks suitable for electronic data processing.

(f) National Bridge Inspection Standards (NBIS). Federal regulations 

establishing requirements for inspection procedures, frequency of 

inspections, qualifications of personnel, inspection reports, and 

preparation and maintenance of a State bridge inventory. The NBIS 

apply to all structures defined as bridges located on all public 

roads.

(g) Public Road. Any road under the jurisdiction of and maintained by 

a public authority and open to public travel.

viii
(h) Structure Inventory and Appraisal (SI&A) Sheet. The graphic 

representation of the data recorded and stored for each NBI record 

in accordance with this Guide.

(i) Strategic Highway Corridor Network (STRAHNET). A system of highways 

which are strategically important to the defense of the United 

States. It includes the Interstate Highways and 25,215 kilometers 

of other non-interstate highways. The Military Traffic Management 

Command Report SE 89-4b-27, Strategic Highway Corridor Network, 

January 1991, contains additional information on STRAHNET. 

(j) STRAHNET Connectors are roads that connect military installations 

and ports of embarkation to the STRAHNET. The connector routes 

represent about 3,042 kilometers of roads that complement STRAHNET.

(k) Indian Reservation Road (IRR). A public road that is located 

within or provides access to an Indian reservation as described in 

Title 23, U.S.C., Sect.101. The terminus of a road providing access 

to an Indian reservation or other Indian land is defined as the 

point at which the road intersects with a road functionally 

classified as a collector or higher classification (outside the 

reservation boundary) in both urban and rural areas. In the case 

of access from an Interstate Highway, the terminus is the first 

interchange outside the reservation.

(l) Land Management Highway System (LMHS). Consists of adjoining state 

and local public roads that provide major public access to Bureau 

of Land Management administered public lands, resources, and 

facilities.

(m) Forest Highway (FH). A road, under the jurisdiction of, and 

maintained by, a public authority and open to public travel; wholly 

or partly within, or adjacent to, and serving the National Forest 

System (NFS) and which is necessary for the protection, 

administration, and utilization of the NFS and the use and 

development of its resources. (23 CFR 660).

(n) Forest Service Development Road. A forest road wholly under the 

jurisdiction of the Forest Service, which may be "open to public 

travel". Bridges on Forest Service Development Roads which are 

"open to public travel" are subject to the NBIS.

ix
(o) Base Highway Network. The Base Highway Network includes the 

through lane (mainline) portions of the NHS, rural/urban principal 

arterial system and rural minor arterial system. Ramps, frontage 

roads and other roadways are not included in the Base Network.

(p) Highway Performance Monitoring System. The Highway Performance 

Monitoring System (HPMS) is a database of universe and sample data 

that describes the nation's public road mileage. The data are 

annually updated and submitted to FHWA by the State Highway 

Agencies, Puerto Rico and the District of Columbia. The universe 

data provides some basic characteristics of all public road mileage 

while the sample of the arterial and collector systems allows for 

assessment of the condition, performance, usage and additional 

characteristics of the nation's major highway systems.

(q) Conversion of Numerical Data. Throughout this Guide the following 

conversion factors are used:

Convert - foot to meter multiply by 0.3048

- mile to kilometer multiply by 1.609 

- english ton to metric ton multiply by .9

(r) Rounding and Truncating of Numerical Data. All numeral values in 

this Guide, except as specifically noted, will follow standard 

rounding criteria, that is, 5 and above will be rounded up to the 

next higher unit and 4 and below will be rounded down to the next 

lower unit. This is applicable to all decimal roundings. In 

certain items where rounding may cause a safety hazard for 

clearance, the numeric measurements will be truncated at the 

appropriate decimal place. This means that a fractional portion 

less than a whole unit will be dropped to the lower whole number, 

for example 2.88 would be truncated to 2.8 when using tenth of a 

meter accuracy. All decimal points are assumed in the locations as 

specified in the Guide. 

(s) Commonly Recognized (CoRe) Structural Elements). A group of 

structural elements endorsed by AASHTO as a means of providing a 

uniform basis for data collection for any bridge management system, 

to enable the sharing of data between States, and to allow for a 

uniform translation of data to NBI Items 58, 59, 60 and 62.

(t) Bridge management System (BMS). A system designed to optimize the 

use of available resources for the inspection, maintenance, 

rehabilitation and replacement of bridges.

x

2000
DATA ITEMS

Item 1 - State Code 3 digits

The first 2 digits are the Federal Information Processing Standards 

(FIPS) code for States, and the third digit is the FHWA region code. 

(New Jersey and New York will retain an FHWA region code of 2.)

 Code State Code State

 014 Alabama 308 Montana

 020 Alaska 317 Nebraska

 049 Arizona 329 Nevada

 056 Arkansas 331 New Hampshire

 069 Californ 342 New Jersey

 088 Colorado 356 New Mexico

 091 Connecti 362 New York

 103 Delaware 374 North Carolina

 113 District of Columbia 388 North Dakota

 124 Florida 395 Ohio

 134 Georgia 406 Oklahoma

 159 Hawaii 410 Oregon

 160 Idaho 423 Pennsylvania

 175 Illinois 441 Rhode Island

 185 Indiana 454 South Carolina

 197 Iowa 468 South Dakota

 207 Kansas 474 Tennessee

 214 Kentucky 486 Texas

 226 Louisiana 498 Utah

 231 Maine 501 Vermont

 243 Maryland 513 Virginia

 251 Massachusetts 530 Washington

 265 Michigan 543 West Virginia

 275 Minnesota 555 Wisconsin

 284 Mississippi 568 Wyoming

 297 Missouri 721 Puerto Rico

Item 2 - Highway Agency District 2 digits

The highway agency district (State or Federal) in which the bridge is 

located shall be represented by a 2-digit code. Existing district 

numbers shall be used where districts are identified by number. Where 

districts are identified by name, a code number shall be assigned based 

on an alphabetical or organizational listing of the districts.

Item 3 - County (Parish) Code 3 digits

Counties shall be identified using the Federal Information Processing 

Standards (FIPS) codes given in the current version of the Census of 

Population and Housing - Geographic Identification Code Scheme.

1
Item 4 - Place Code 5 digits

Cities, towns, townships, villages, and other census-designated places 

shall be identified using the Federal Information Processing Standards 

(FIPS) codes given in the current version of the Census of Population 

and Housing - Geographic Identification Code Scheme. If there is no 

FIPS place code, then code all zeros.

Item 5 - Inventory Route 9 digits

The inventory route is a 9-digit code composed of 5 segments.

 Segment Description Length

 5A Record Type 1 digit

 5B Route Signing Prefix 1 digit

 5C Designated Level of Service 1 digit

 5D Route Number 5 digits

 5E Directional Suffix 1 digit

Item 5A - Record Type 1 digit

There are two types of National Bridge Inventory records: "on" and 

"under". Code the first digit (leftmost) using one of the following 

codes:

 Code Description

 1 Route carried "on" the structure

 2 Single route goes "under" the structure

 A through Z Multiple routes go "under" the structure

 A signifies the first of multiple routes under the structure.

 B signifies the second of multiple routes under the structure.

 Z signifies 26 routes under the structure.

"On" signifies that the inventory route is carried "on" the structure. 

Each bridge structure carrying highway traffic must have a record 

identified with a type code = 1 (numeric). All of the NBI data items 

must be coded, unless specifically excepted, with respect to the 

structure and the inventory route "on" it.

"Under" signifies that the inventory route goes "under" the structure. 

If an inventory route beneath the structure is a Federal-aid highway, is 

a STRAHNET route or connector or is otherwise important, a record must 

be coded to identify it. The type code must be 2 or an alphabetic 

letter A through Z. Code 2 for a single route under the structure. If 

2 or more routes go under a structure on separate roadways, the code of 

2 shall not be used. Code A, B, C, D, etc. consecutively for multiple 

routes on separate roadways under the same structure. STRAHNET routes 

shall be listed first. When this item is coded 2 or A through Z, only 

the following items must be coded: Items 1, 3-13, 16, 17, 19, 20, 26-

30, 42, 43, 47-49, 100-104, 109 and 110. All other items may remain 

blank.

2
Item 5A - Record Type (cont'd)

It cannot be overemphasized that all route-oriented data must agree with 

the coding as to whether the inventory route is "on" or "under" the 

structure.

Tunnels shall be coded only as an "under" record; that is, they shall 

not be coded as a structure carrying highway traffic.

There are situations of a route "under" a structure, where the structure 

does not carry a highway, but may carry a railroad, pedestrian traffic, 

or even a building. These are coded the same as any other "under" 

record and no "on" record shall be coded.

Item 5B - Route Signing Prefix 1 digit

In the second position, identify the route signing prefix for the 

inventory route using one of the following codes:

 Code Description

 1 Interstate highway

 2 U.S. numbered highway

 3 State highway

 4 County highway

 5 City street

 6 Federal lands road

 7 State lands road

 8 Other (include toll roads not otherwise

 indicated or identified above)

When 2 or more routes are concurrent, the highest class of route will be 

used. The hierarchy is in the order listed above.

Item 5C - Designated Level of Service 1 digit

In the third position, identify the designated level of service for the 

inventory route using one of the following codes:

 Code Description

 0 None of the below

 1 Mainline

 2 Alternate

 3 Bypass

 4 Spur

 6 Business

 7 Ramp, Wye, Connector, etc.

 8 Service and/or unclassified frontage road

3
Item 5D - Route Number 5 digits

Code the route number of the inventory route in the next 5 positions. 

This value shall be right justified in the field with leading zeros 

filled in. (See examples below.)

If concurrent routes are of the same hierarchy level, denoted by the 

route signing prefix, the lowest numbered route shall be coded. Code

00000 for bridges on roads without route numbers.

Item 5E - Directional Suffix 1 digit

In the last position, code the directional suffix to the route number of 

the inventory route when it is part of the route number, using one of 

the following codes:

 Code Description

 0 Not applicable

 1 North

 2 East

 3 South

 4 West

In some cases, letters may be used with route numbers and as part of the 

route numbers and not to indicate direction. In such cases, the letter 

should be included in the 5-position route number field.

EXAMPLES: Record Code

 Interstate 95, on 1 1 1 00095 0 111000950

 Interstate 70S, under 2 1 1 00070 3 211000703

 State Highway 104, Spur, under 2 3 4 00104 0 234001040

 U.S. 30E Bypass, on 1 2 3 00030 2 123000302

 City street, on 1 5 0 00000 0 150000000

 Ramp from I-81, under 2 1 7 00081 0 217000810

 County Highway 173 on 1 4 1 00173 0 141001730

 Interstate 84 under 2 1 1 00084 0 211000840

 Interstate 495 on 1 1 1 00495 0 111004950

 State Hwy 120 (STRAHNET Rte) under A 3 1 00120 0 A31001200

 Alternate State Hwy 130 under B 3 2 00130 0 B32001300

 Tunnel on Interstate 70 2 1 1 00070 0 211000700

4
Item 6 - Features Intersected 25 digits

This item contains a description of the features intersected by the 

structure and a critical facility indicator. When Item 5A indicates an 

"under" record, this item describes the inventory route and/or features 

under the structure. There are 25 digits divided into 2 segments.

 Segment Description Length

 6A Features Intersected 24 digits

 6B No Longer Coded (Blank) 1 digit

The information to be recorded for this item in the first 24 digits 

shall be the name or names of the features intersected by the structure. 

 When one of the features intersected is another highway, the signed 

number or name of the highway shall appear first (leftmost) in the 

field. The names of any other features shall follow, separated by a 

semicolon or a comma. Parentheses shall be used to provide a second 

identification of the same feature (see third example). Abbreviations 

may be used where necessary, but an effort shall be made to keep them 

meaningful. The data in this segment shall be left justified in the 

first 24 positions without trailing zeros.

EXAMPLES:

 I 81, US 51, MILL ROAD 

 MISSISSIPPI RIVER

 SR 42 (POND ROAD)

Item 7 - Facility Carried by Structure 18 digits

The facility being carried by the structure shall be recorded and coded. 

 In all situations this item describes the use "on" the structure. This 

item shall be left justified without trailing zeros.

EXAMPLES:

 US 66

 MAIN STREET

 COUNTY ROAD 450

 C & 0 RAILROAD (appropriate for "under" record only)

 PEDESTRIAN BRIDGE (appropriate for "under" record only)

5

2000
Item 8 - Structure Number 15 digits

It is required that the official structure number be recorded. It is 

not necessary to code this number according to an arbitrary national 

standard. Each agency should code the structure number according to its 

own internal processing procedures. When recording and coding for this 

item and following items, any structure or structures with a closed 

median should be considered as one structure, not two. Closed medians 

may have either mountable or non-mountable curbs or barriers.

The structure number must be unique for each bridge within the State, 

and once established should preferably never change for the life of the 

bridge. If it is essential that structure number(s) must be changed, 

all 15 digits are to be filled. For any structure number changes, a 

complete cross reference of corresponding "old" and "new" numbers must 

be provided to the FHWA Bridge Division. The cross reference shall 

include both a computer tape or diskette and a printed listing in the 

FHWA required format.

The identical structure number must appear on the "on" and all "under" 

records associated with a particular structure. (Refer to Item 5 -

Inventory Route).

Item 9 - Location 25 digits

This item contains a narrative description of the bridge location. It 

is recommended that the location be keyed to a distinguishable feature 

on an official highway department map such as road junctions and 

topographical features. This item shall be left justified without 

trailing zeros.

EXAMPLES:

 6 km SW. OF RICHMOND

 3.5 km S. OF JCT. SR 69

Item 10 - Inventory Route, Minimum Vertical Clearance 4 digits

 (XX.XX meters)

Code the minimum vertical clearance over the inventory route identified 

in Item 5, whether the route is "on" the structure or "under" the 

structure. The minimum clearance for a 3-meter width of the pavement or 

traveled part of the roadway where the clearance is the greatest shall 

be recorded and coded as a 4-digit number truncated to the hundredth of 

a meter (with an assumed decimal point). For structures having multiple 

openings, clearance for each opening shall be recorded, but only the 

greatest of the "minimum clearances" for the two or more openings shall 

be coded regardless of the direction of travel. This would be the 

practical maximum clearance. When no restriction exists or when the 

restriction is 30 meters or greater, code 9999. Coding of actual 

clearances between 30.0 and 99.99 meters to an exact measurement is 

optional.

6
Item 11 - Kilometerpoint (XXXX.XXX) 7 digits

The linear referencing system (LRS) kilometerpoint is used to establish 

the location of the bridge on the Base Highway Network (see Item 12). 

It must be from the same LRS Inventory Route and kilometerpoint system 

as reported in the Highway Performance Monitoring System (HPMS). The 

kilometerpoint coded in this item directly relates to Item 13 - LRS 

Inventory Route, Subroute Number. 

This item must be coded for all structures located on or overpassing the 

Base Highway Network. Code a 7-digit number to represent the LRS 

kilometer-point distance in kilometers to the nearest thousandth (with 

an assumed decimal point). For structures carrying the LRS Inventory 

Route, code the kilometerpoint at the beginning of the structure (i.e. 

the lowest kilometer-point on the bridge). When the LRS Inventory Route 

goes under the structure (Item 5A coded 2 or A-Z), then code the 

kilometerpoint on the underpassing route where the structure is first 

encountered. 

Code all zeros in this field for all records where kilometerpoints are 

not provided. Kilometerpoints may be coded for bridges that are not 

located on the Base Highway Network, however Item 12 - Base Highway 

Network shall be coded 0 for these records. 

The kilometerpoint is coded aligned to the assumed decimal point and 

zero filled where needed to fill the 7 digits. 

EXAMPLES: Code

 Kilometerpoint is 130.34 0130340

 Kilometerpoint is 9.60 0009600

Item 12 - Base Highway Network 1 digit 

This item is to be coded for all records in the inventory. The Base 

Highway Network includes the through lane (mainline) portions of the 

NHS, rural/urban principal arterial system and rural minor arterial 

system. Ramps, frontage roads and other roadways are not included in 

the Base Network. For the inventory route identified in Item 5 -

Inventory Route, indicate whether the inventory route is on the Base 

Highway Network or not on that network. Use one of the following codes: 

 Code Description

 0 Inventory Route is not on the

 Base Network

 1 Inventory Route is on the Base

 Network

7
Item 13 - LRS Inventory Route, Subroute Number 12 digits

If Item 12 - Base Highway Network has been coded 1, the information to 

be recorded for this item is inventory route for the State's linear 

referencing system (LRS). If Item 12 has been coded 0, this entire item 

should be left blank. This item is a 12-digit code composed of 2 

segments.

 Segment Description Length

 13A LRS Inventory Route 10 digits

 13B Subroute Number 2 digits

The LRS inventory route and subroute numbers to be reported in this item 

must correspond to the LRS inventory route and subroute numbers reported 

by the State for the HPMS. The LRS inventory route number is coded in 

the ten positions of segment 13A, right justified and zero filled. The 

subroute number, if it exists, is coded in the two positions of segment 

13B, right justified and zero filled.

The LRS inventory route number can be alphanumeric, but must not contain 

blanks. The LRS inventory route number is not necessarily the same as 

that posted along the roadway, but is a number used to uniquely identify 

a route within at least a county and perhaps throughout the State.

The subroute number is a number that uniquely identifies portions of an 

inventory route sections where duplicate kilometerpoints occur. These 

subroute numbers, if they exist, are identified in the State's HPMS-LRS 

records. If there is no subroute number, code 00 in this segment.

EXAMPLES: Code

 Inventory Route 2775, Subroute Number 0 000000277500

 Inventory Route 2775, Subroute Number 3 000000277503

Item 14 and Item 15

(Reserved)

Item 16 - Latitude (XX degrees XX minutes XX.XX seconds) 8 digits

For bridges on STRAHNET and STRAHNET Connector highways and on the NHS, 

record and code the latitude of each in degrees, minutes and seconds to 

the nearest hundredth of a second (with an assumed decimal point). The 

point of the coordinate may be the beginning of the bridge in the 

direction of the inventory or any other consistent point of reference on 

the bridge which is compatible with the LRS. If the bridge is not on a 

STRAHNET highway or the NHS, a code of all zeros is acceptable, but it 

is preferable to code the latitude if available.

8
Item 16 - Latitude (cont'd)

The reason for the increased precision is to facilitate the use of 

Global Positioning System (GPS) data directly into this item. The 

increased precision is not currently mandatory and, if GPS readings are 

not available, the current measuring methods and level of precision may 

continue to be used. The minimum precision should be to the nearest 

minute, but the preferred precision is to the nearest hundredth of a 

second using GPS methods.

EXAMPLE: Code

 Latitude is 35°27.3' (current precision) 35271800

 (acceptable coding) 35270000

 35°27'18.55" (GPS reading) 35271855

Item 17 - Longitude (XXX degrees XX minutes XX.XX seconds) 9 digits

For bridges on STRAHNET and STRAHNET Connector highways and on the NHS, 

record and code the longitude of each in degrees, minutes and seconds to 

the nearest hundredth of a second (with an assumed decimal point). A 

leading zero shall be coded where needed. The point of the coordinate 

may be the beginning of the bridge in the direction of the inventory or 

any other consistent point of reference on the bridge which is 

compatible with the LRS. If the bridge is not on a STRAHNET highway or 

the NHS, a code of all zeros is acceptable, but it is preferable to code 

the longitude if available.

The reason for the increased precision is to facilitate the use of 

Global Positioning System (GPS) data directly into this item. The 

increased precision is not currently mandatory and, if GPS readings are 

not available, the current measuring methods and level of precision may 

continue to be used. The minimum precision should be to the nearest 

minute, but the preferred precision is to the nearest hundredth of a 

second using GPS methods.

EXAMPLE: Code

 Longitude is 81°5.8' (current precision) 081054800

 (acceptable coding) 081060000

 81°5'50.65" (GPS reading) 081055065

Item 18

(reserved)

9
Item 19 - Bypass, Detour Length (XXX kilometers) 3 digits

Indicate the actual length to the nearest kilometer of the detour 

length. The detour length should represent the total additional travel 

for a vehicle which would result from closing of the bridge. The factor 

to consider when determining if a bypass is available at the site is the 

potential for moving vehicles, including military vehicles, around the 

structure. This is particularly true when the structure is in an 

interchange. For instance, a bypass likely would be available in the 

case of diamond interchanges, interchanges where there are service roads 

available, or other interchanges where the positioning and layout of the 

ramps is such that they could be used without difficulty to get around 

the structure. If a ground level bypass is available at the structure 

site for the inventory route, record and code the detour length as 000.

If the bridge is one of twin bridges and is not at an interchange, code 

001 where the other twin bridge can be used as a temporary bypass with a 

reasonable amount of crossover grading. The detour route will be 

established following allowable criteria determined by the governing 

authority. (Some authorities will not allow a designated detour over a 

road or bridge of lesser "quality.") Code 199 for 199 kilometers or 

more.

EXAMPLES: Code

 Diamond interchange, structure bypassable 000

 Cloverleaf, not bypassable; 18-kilometer detour 018

 Structure over river; 121-kilometer detour 121

 Structure over highway, no interchange,

 bypassable at ground level 000

 Structure on dead end road 199

Bypass, Detour Length A to B = 4 kilometers

10
Item 19 - Bypass, Detour Length (cont'd)

Bypass, Detour Length A to B = 0 kilometers

Item 20 - Toll 1 digit

The toll status of the structure is indicated by this item. Interstate 

toll segments under Secretarial Agreement (Title 23 - United States Code 

- Highways Section 129 as amended by 1991 ISTEA and prior legislation) 

shall be identified separately. Use one of the following codes:

 Code Description

 1 Toll bridge. Tolls are paid specifically to use 

the structure.

 2 On toll road. The structure carries a toll road, 

that is, tolls are paid to use the facility, which 

includes both the highway and the structure.

 3 On free road. The structure is toll-free and 

carries a toll-free highway.

 4 On Interstate toll segment under Secretarial 

Agreement. Structure functions as a part of the 

toll segment.

 5 Toll bridge is a segment under Secretarial

Agreement. Structure is separate agreement from 

highway segment.

11
Item 21 - Maintenance Responsibility 2 digits

The actual name(s) of the agency(s) responsible for the maintenance of 

the structure shall be recorded on the inspection form. The codes below 

shall be used to represent the type of agency that has primary 

responsibility for maintaining the structure. If more than one agency 

has equal maintenance responsibility, code one agency in the hierarchy 

of State, Federal, county, city, railroad, and other private.

 Code Description

 01 State Highway Agency

 02 County Highway Agency

 03 Town or Township Highway Agency

 04 City or Municipal Highway Agency

 11 State Park, Forest, or Reservation Agency

 12 Local Park, Forest, or Reservation Agency

 21 Other State Agencies

 25 Other Local Agencies

 26 Private (other than railroad)

 27 Railroad

 31 State Toll Authority

 32 Local Toll Authority

 60 Other Federal Agencies (not listed below)

 61 Indian Tribal Government

 62 Bureau of Indian Affairs

 63 Bureau of Fish and Wildlife

 64 U.S. Forest Service

 66 National Park Service

 67 Tennessee Valley Authority

 68 Bureau of Land Management

 69 Bureau of Reclamation

 70 Corps of Engineers (Civil)

 71 Corps of Engineers (Military) 

 72 Air Force 

 73 Navy/Marines 

 74 Army 

 75 NASA 

 76 Metropolitan Washington Airports Service 

 80 Unknown 

Item 22 - Owner 2 digits

The actual name(s) of the owner(s) of the bridge shall be recorded on

the inspection form. The codes used in Item 21 - Maintenance 

Responsibility shall be used to represent the type of agency that is the 

primary owner of the structure. If more than one agency has equal 

ownership, code one agency in the hierarchy of State, Federal, county, 

city, railroad, and other private.

Item 23 through Item 25

(Reserved)

12

2000
Item 26 - Functional Classification of Inventory Route 2 digits

For the inventory route, code the functional classification using one of 

the following codes:

 Code Description

 Rural

 01 Principal Arterial - Interstate

 02 Principal Arterial - Other

 06 Minor Arterial

 07 Major Collector

 08 Minor Collector

 09 Local

 Urban

 11 Principal Arterial - Interstate

 12 Principal Arterial - Other Freeways or

 Expressways

 14 Other Principal Arterial

 16 Minor Arterial

 17 Collector

 19 Local

The bridge shall be coded rural if not inside a designated urban area. 

The urban or rural designation shall be determined by the bridge 

location and not the character of the roadway.

Item 27 - Year Built 4 digits

Record and code the year of construction of the structure. Code all 4 

digits of the year in which construction of the structure was completed. 

 If the year built is unknown, provide a best estimate. See also Item 

106 - Year Reconstructed.

EXAMPLES: Code

 Construction completed 1956 1956

 1892 1892

13
Item 28 - Lanes On and Under the Structure 4 digits

Record and code the number of lanes being carried by the structure and 

being crossed over by the structure as a 4-digit number composed of 2 

segments. The number of lanes should be right justified in each segment 

with leading zero(s) coded as required.

 Segment Description Length

 28A Lanes on the structure 2 digits

 28B Lanes under the structure 2 digits

Include all lanes carrying highway traffic (i.e., cars, trucks, buses) 

which are striped or otherwise operated as a full width traffic lane for 

the entire length of the structure or under the structure by the 

owning/maintaining authority. This shall include any full width merge 

lanes and ramp lanes, and shall be independent of directionality of 

usage (i.e., a 1-lane bridge carrying 2-directional traffic is still 

considered to carry only one lane on the structure). It should be noted 

here that for the purpose of evaluating the Deck Geometry - Item 68, any 

"1-lane" bridge, not coded as a ramp (Item 5C = 7), which has a Bridge 

Roadway Width, Curb-to-Curb - Item 51 coded 4.9 meters or greater shall 

be evaluated as 2 lanes.

When the inventory route is "on" the bridge (the first digit of Item 5 -

Inventory Route is coded 1), the sum of the total number of lanes on all 

inventoried routes under the bridge shall be coded. When the inventory 

route is "under" the bridge (the first digit of Item 5 - Inventory Route 

is coded 2 or A through Z), only the number of lanes being identified by 

that "under" record shall be coded in Item 28B.

When the inventory route is "under" the structure, the obstruction over 

the inventory route may be other than a highway bridge (railroad, 

pedestrian, pipeline, etc.). Code 00 for these cases if there are no 

highway lanes on the obstructing structure.

Double deck bridges may be coded as 1 or 2 structures as noted in the 

examples on the next page. Either method is acceptable, however, all 

related data must be compatible with the method selected.

14
Item 28 - Lanes On and Under the Structure (cont'd)

EXAMPLES*: Code

 1 lane on, 0 lanes under 0100

 3 lanes on, 1 lane under 0301

 8 lanes on 2-way, 12 lanes under ** 0812

 5 lanes on double deck each direction,

 2 lanes under 1002***

 5 lanes on double deck each direction,

 2 lanes under 0502****

 Railroad and pedestrian on, 4 lanes under 0004

* For the inventory route on the bridge, the first digit of Item 5 -

 Inventory Route is coded 1.

** This example has 3 inventory routes under the bridge of 6, 4, and

 2 lanes of 2-way traffic respectively. When coding an "under"

 record for each of these inventory routes, the first digit of

 Item 5 - Inventory Route is coded A, B, and C, and Item 28 is

 coded 0806, 0804, and 0802 respectively for the 3 required

 records.

***Acceptable if coded as 1 bridge. However, other data such as

 ADT, curb- to-curb width, etc., must be for both decks

 (preferred method).

****Acceptable if coded as 2 separate bridges. However, other data

 such as ADT, curb-to-curb width, etc., must be for a single deck.

Item 29 - Average Daily Traffic 6 digits

Code a 6-digit number that shows the average daily traffic volume for 

the inventory route identified in Item 5. Make certain the unit's 

position is coded even if estimates of ADT are determined to tens or 

hundreds of vehicles; that is, appropriate trailing zeros shall be 

coded. The ADT coded should be the most recent ADT counts available. 

Included in this item are the trucks referred to in Item 109 - Average 

Daily Truck Traffic. If the bridge is closed, code the actual ADT from 

before the closure occurred.

The ADT must be compatible with the other items coded for the bridge. 

For example, parallel bridges with an open median are coded as follows: 

 if Item 28 - Lanes On and Under the Structure and Item 51 - Bridge 

Roadway Width, Curb-to-Curb are coded for each bridge separately, then 

the ADT must be coded for each bridge separately (not the total ADT for 

the route).

EXAMPLES: Code

 Average Daily Traffic 540 000540

 15,600 015600

 24,000 024000

15
Item 30 - Year of Average Daily Traffic 4 digits

Record the year represented by the ADT in Item 29. Code all four digits 

of the year so recorded.

EXAMPLE: Code

 Year of ADT is 1994 1994

Item 31 - Design Load 1 digit

Use the codes below to indicate the live load for which the structure 

was designed. The numerical value of the railroad loading should be 

recorded on the form. Classify any other loading, when feasible, using 

the nearest equivalent of the loadings given below.

 Metric English 

 Code Description Description

 1 M 9 or H 10

 2 M 13.5 H 15 

 3 MS 13.5 HS 15

 4 M 18 H 20

 5 MS 18 HS 20

 6 MS 18+Mod HS 20+Mod

 7 Pedestrian Pedestrian

 8 Railroad Railroad

 9 MS 22.5 HS 25 

 0 Other or Unknown (describe on 

 inspection reporting form)

Item 32 - Approach Roadway Width (XXX.X meters) 4 digits

Code a 4-digit number to represent the normal width of usable roadway 

approaching the structure measured to the nearest tenth of a meter (with 

an assumed decimal point). Usable roadway width will include the width 

of traffic lanes and the widths of shoulders where shoulders are defined 

as follows:

Shoulders must be constructed and normally maintained flush 

with the adjacent traffic lane, and must be structurally 

adequate for all weather and traffic conditions consistent 

with the facility carried.

Unstabilized grass or dirt, with no base course, flush with and beside 

the traffic lane is not to be considered a shoulder for this item.

For structures with medians of any type and double-decked structures, 

this item should be coded as the sum of the usable roadway widths for 

the approach roadways (i.e., all median widths which do not qualify as 

shoulders should not be included in this dimension). When there is a 

variation between the approaches at either end of the structure, record 

and code the most restrictive of the approach conditions.

16
Item 32 - Approach Roadway Width (cont'd)

 EXAMPLES:

 Left Left Median Right Right

 Shoulder Roadway Shoulders Roadway Shoulder Code

 1.2 - - 4.8 1.8 0078

 1.8 - - 10.8 3.6 0162

 3.6 14.4 9.0 14.4 3.6 0450

 3.0 7.2 4.8 10.8 3.0 0288

The last example above represents the coding method for a structure in 

which the most restrictive approach has the cross-section shown below:

Regardless of whether the median is open or closed, the data coded must 

be compatible with the other related route and bridge data (i.e., if 

Item 51 - Bridge Roadway Width, Curb-to-Curb is for traffic in one 

direction only, then Items 28, 29, 32, etc. must be for traffic in one 

direction only).

If a ramp is adjacent to the through lanes approaching the structure, it 

shall be included in the approach roadway width. The total approach 

roadway width for the example below is 29.2 meters (a code of 292).

17
Item 33 - Bridge Median 1 digit

Indicate with a 1-digit code if the median is non-existent, open or 

closed. The median is closed when the area between the 2 roadways at 

the structure is bridged over and is capable of supporting traffic. All 

bridges that carry either 1-way traffic or 2-way traffic separated only 

by a centerline will be coded 0 for no median.

 Code Description

 0 No median

 1 Open median

 2 Closed median (no barrier)

 3 Closed median with non-mountable barriers

18
Item 34 - Skew (XX degrees) 2 digits

The skew angle is the angle between the centerline of a pier and a line 

normal to the roadway centerline. When plans are available, the skew 

angle can be taken directly from the plans. If no plans are available, 

the angle is to be field measured if possible. Record the skew angle to 

the nearest degree. If the skew angle is 0E, it should be so coded. 

When the structure is on a curve or if the skew varies for some other 

reason, the average skew should be recorded, if reasonable. Otherwise, 

record 99 to indicate a major variation in skews of substructure units. 

 A 2-digit number should be coded.

EXAMPLES: Code

 Skew angle 0° 00

 10° 10

 8° 08

 29° 29

Item 35 - Structure Flared 1 digit

Code this item to indicate if the structure is flared (i.e., the width 

of the structure varies). Generally, such variance will result from 

ramps converging with or diverging from the through lanes on the 

structure, but there may be other causes. Minor flares at ends of 

structures should be ignored.

 Code Description

 0 No flare

 1 Yes, flared

Item 36 - Traffic Safety Features 4 digits

Bridge inspection shall include the recording of information on the 

following traffic safety features so that the evaluation of their 

adequacy can be made.

(A) Bridge railings: Some factors that affect the proper functioning of 

bridge railing are height, material, strength, and geometric 

features. Railings must be capable of smoothly redirecting an 

impacting vehicle. Bridge railings should be evaluated using the 

current AASHTO Standard Specifications for Highway Bridges, which 

calls for railings to meet specific geometric criteria and to resist 

specified static loads without exceeding the allowable stresses in 

their elements. Bridge railing should be crash tested per FHWA 

policy. Railings that meet these criteria and loading conditions 

are considered acceptable. Other railings that have been 

successfully crash tested are considered acceptable even though they 

may not meet the static loading analysis and geometric requirements. 

 Acceptable guidelines for bridge railing design and testing are 

also found in the AASHTO Guide Specifications for Bridge Railings

1989. Additional guidance for testing is found in National 

Cooperative Highway Research Program - Report 350 Recommended 

Procedures for the Safety Performance Evaluation of Highway Features

1993.

19
Item 36 - Traffic Safety Features (cont'd)

(B) Transitions: The transition from approach guardrail to bridge 

railing requires that the approach guardrail be firmly attached to 

the bridge railing. It also requires that the approach guardrail be 

gradually stiffened as it comes closer to the bridge railing. The 

ends of curbs and safety walks need to be gradually tapered out or 

shielded.

(C) Approach guardrail: The structural adequacy and compatibility of 

approach guardrail with transition designs should be determined. 

Rarely does the need for a barrier stop at the end of a bridge. 

Thus, an approach guardrail with adequate length and structural 

qualities to shield motorists from the hazards at the bridge site 

needs to be installed. In addition to being capable of safely 

redirecting an impacting vehicle, the approach guardrail must also 

facilitate a transition to the bridge railing that will not cause 

snagging or pocketing of an impacting vehicle. Acceptable 

guardrail design suggestions are contained in the AASHTO Roadside 

Design Guide and subsequent FHWA or AASHTO guidelines.

(D) Approach guardrail ends: As with guardrail ends in general, the 

ends of approach guardrails to bridges should be flared, buried, 

made breakaway, or shielded. Design treatment of guardrail ends is 

given in the AASHTO Roadside Design Guide.

The data collected shall apply only to the route on the bridge. 

Collision damage or deterioration of the elements are not considered 

when coding this item. Traffic safety features is a 4-digit code 

composed of 4 segments.

 Segment Description Length

 36A Bridge railings 1 digit

 36B Transitions 1 digit

 36C Approach guardrail 1 digit

 36D Approach guardrail ends 1 digit

The reporting of these features shall be as follows:

 Code Description

 0 Inspected feature does not meet currently 

acceptable standards or a safety feature is 

required and none is provided.*

 1 Inspected feature meets currently acceptable 

standards.*

 N Not applicable or a safety feature is not 

required.*

* For structures on the NHS, national standards are set by regulation. 

 For those not on the NHS, it shall be the responsibility of the 

highway agency (state, county, local or federal) to set standards.

20
Item 36 - Traffic Safety Features (cont'd)

EXAMPLE: Code

 All features meet currently acceptable

 standards except transition 1011

Item 37 - Historical Significance 1 digit

The historical significance of a bridge involves a variety of 

characteristics: the bridge may be a particularly unique example of the 

history of engineering; the crossing itself might be significant; the 

bridge might be associated with a historical property or area; or 

historical significance could be derived from the fact the bridge was 

associated with significant events or circumstances. Use one of the 

following codes:

 Code Description

 1 Bridge is on the National Register of Historic 

Places.

 2 Bridge is eligible for the National Register 

of Historic Places.

 3 Bridge is possibly eligible for the National 

Register of Historic Places (requires further 

 investigation before determination can be 

made) or bridge is on a State or local 

historic register.

 4 Historical significance is not determinable at 

this time.

 5 Bridge is not eligible for the National 

Register of Historic Places.

Item 38 - Navigation Control 1 digit

Indicate for this item whether or not navigation control (a bridge 

permit for navigation) is required. Use one of the following codes:

 Code Description

 N Not applicable, no waterway.

 0 No navigation control on waterway (bridge 

permit not required).

 1 Navigation control on waterway (bridge permit 

required).

21
Item 39 - Navigation Vertical Clearance (XXX.X meters) 4 digits

If Item 38 - Navigation Control has been coded 1, record the minimum 

vertical clearance imposed at the site as measured above a datum that is 

specified on a navigation permit issued by a control agency. The 

measurement shall be coded as a 4-digit number truncated to the tenth of 

a meter (with an assumed decimal point). This measurement will show the 

clearance that is allowable for navigational purposes. In the case of a 

swing or bascule bridge, the vertical clearance shall be measured with 

the bridge in the closed position (i.e., open to vehicular traffic). 

The vertical clearance of a vertical lift bridge shall be measured with 

the bridge in the raised or open position. Also, Item 116 - Minimum 

Navigation Vertical Clearance Vertical Lift Bridge shall be coded to 

provide clearance in a closed position. If Item 38 - Navigation Control 

has been coded 0 or N, code 000 to indicate not applicable.

EXAMPLES: Code

Measured Vertical

Clearance 50.00 meters 0500

 20.65 meters 0206

 24.28 meters 0242

Item 40 - Navigation Horizontal Clearance (XXXX.X meters) 5 digits

If Item 38 - Navigation Control has been coded 1, record the horizontal 

clearance measurement imposed at the site that is shown on the 

navigation permit. This may be less than the structure geometry allows. 

 If a navigation permit is required but not available, use the minimum 

horizontal clearance between fenders, if any, or the clear distance 

between piers or bents. Code the clearance as a 5-digit number 

truncated to the tenth of a meter (with an assumed decimal point). If 

Item 38 - Navigation Control has been coded 0 or N, code 0000 to 

indicate not applicable.

EXAMPLES: Code

 Horizontal Clearance 53.57 meters 00535

 95.00 meters 00950

 202.09 meters 02020

Item 41 - Structure Open, Posted, or Closed to Traffic 1 digit

This item provides information about the actual operational status of a 

structure. The field review could show that a structure is posted, but 

Item 70 - Bridge Posting may indicate that posting is not required. 

This is possible and acceptable coding since Item 70 is based on the 

operating stress level and the governing agency's posting procedures may 

specify posting at some stress level less than the operating rating. 

One of the following codes shall be used:

22
Item 41 - Structure Open, Posted, or Closed to Traffic (cont'd)

 Code Description

 A Open, no restriction

 B Open, posting recommended but not legally 

implemented (all signs not in place or not 

correctly implemented)

 D Open, would be posted or closed except for 

temporary shoring, etc. to allow for 

unrestricted traffic

 E Open, temporary structure in place to carry 

legal loads while original structure is 

closed and awaiting replacement or 

rehabilitation

 G New structure not yet open to traffic

 K Bridge closed to all traffic

 P Posted for load (may include other 

restrictions such as temporary bridges which 

are load posted)

 R Posted for other load-capacity restriction 

(speed, number of vehicles on bridge, etc.)

Item 42 - Type of Service 2 digits

The type of service on the bridge and under the bridge is indicated by a 

2-digit code composed of 2 segments.

 Segment Description Length

 42A Type of service on bridge 1 digit

 42B Type of service under bridge 1 digit

The first digit indicates the type of service "on" the bridge and shall 

be coded using one of the following codes:

 Code Description

 1 Highway

 2 Railroad

 3 Pedestrian-bicycle

 4 Highway-railroad

 5 Highway-pedestrian

 6 Overpass structure at an interchange or

 second level of a multilevel interchange

 7 Third level (Interchange)

 8 Fourth level (Interchange)

 9 Building or plaza

 0 Other

23
Item 42 - Type of Service (cont'd)

The second digit indicates the type of service "under" the bridge and 

shall be coded using one of the following codes:

 Code Description

 1 Highway, with or without pedestrian

 2 Railroad

 3 Pedestrian-bicycle

 4 Highway-railroad

 5 Waterway

 6 Highway-waterway

 7 Railroad-waterway

 8 Highway-waterway-railroad

 9 Relief for waterway

 0 Other

Item 43 - Structure Type, Main 3 digits

Record the description on the inspection form and indicate the type of 

structure for the main span(s) with a 3-digit code composed of 2 

segments.

Segment Description Length

 43A Kind of material and/or design 1 digit

 43B Type of design and/or construction 2 digits

The first digit indicates the kind of material and/or design and shall 

be coded using one of the following codes:

 Code Description

 1 Concrete

 2 Concrete continuous

 3 Steel

 4 Steel continuous

 5 Prestressed concrete *

 6 Prestressed concrete continuous *

 7 Wood or Timber

 8 Masonry

 9 Aluminum, Wrought Iron, or Cast Iron

 0 Other

* Post-tensioned concrete should be coded as prestressed concrete.

24
Item 43 - Structure Type, Main (cont'd)

The second and third digits indicate the predominant type of design 

and/or type of construction and shall be coded using one of the 

following codes:

 Code Description

 01 Slab

 02 Stringer/Multi-beam or Girder

 03 Girder and Floorbeam System

 04 Tee Beam

 05 Box Beam or Girders - Multiple

 06 Box Beam or Girders - Single or Spread

 07 Frame (except frame culverts)

 08 Orthotropic

 09 Truss - Deck

 10 Truss - Thru

 11 Arch - Deck

 12 Arch - Thru

 13 Suspension

 14 Stayed Girder

 15 Movable - Lift

 16 Movable - Bascule

 17 Movable - Swing

 18 Tunnel

 19 Culvert (includes frame culverts)

 20 * Mixed types

 21 Segmental Box Girder

 22 Channel Beam

 00 Other

* Applicable only to approach spans - Item 44

EXAMPLES: Code

 Wood or Timber Through Truss 710

 Masonry Culvert 819

 Steel Suspension 313

 Continuous Concrete Multiple Box Girders 205

 Simple Span Concrete Slab 101

 Tunnel in Rock 018

Item 44 - Structure Type, Approach Spans 3 digits

Indicate with a 3-digit code composed of 2 segments, the type of 

structure for the approach spans to a major bridge or for the spans 

where the structural material is different. The codes are the same as 

for Item 43 preceding. However, code 000 if this item is not 

applicable. Use code 20 (Item 44B) when no one type of design and/or 

construction is predominate for the approach units. If the kind of 

material (Item 44A) is varied, code the most predominant.

25
Item 44 - Structure Type, Approach Spans (cont'd)

Segment Description Length

 44A Kind of material and/or design 1 digit

 44B Type of design and/or construction 2 digits

 EXAMPLES: Code

 Simple prestressed concrete I-beam 502

 Continuous concrete T-beam 204

 Continuous steel deck truss 409

Item 45 - Number of Spans in Main Unit 3 digits

Record the number and indicate with a 3-digit number the number of spans 

in the main or major unit. This item will include all spans of most 

bridges, the major unit only of a sizable structure, or a unit of 

material or design different from that of the approach spans.

Item 46 - Number of Approach Spans 4 digits

Record the number and indicate with a 4-digit number the number of spans 

in the approach spans to the major bridge, or the number of spans of 

material different from that of the major bridge.

Item 47 - Inventory Route, Total Horizontal Clearance 3 digits

 (XX.X meters)

The total horizontal clearance for the inventory route identified in 

Item 5 should be measured and recorded. The clearance should be the 

available clearance measured between the restrictive features -- curbs, 

rails, walls, piers or other structural features limiting the roadway 

(surface and shoulders). The measurement should be recorded and coded 

as a 3-digit number truncated to the nearest tenth of a meter (with an 

assumed decimal point). When the restriction is 100 meters or greater, 

code 999.

The purpose of this item is to give the largest available clearance for 

the movement of wide loads. Flush and mountable medians are not 

considered to be restrictions. This clearance is defined in 2 ways; use 

the most applicable:

 1. Clear distance between restrictions of the inventory route 

either "on" or "under" the structure.

 2. Roadway surface and shoulders - when there are no restrictions.

For a divided facility with a raised or non-mountable median, or an 

"under" route divided by piers, record the greater of the restricted 

widths in either direction, not both directions.

26
Item 47 - Inventory Route, Total Horizontal Clearance (cont'd)

EXAMPLES:

Item 48 - Length of Maximum Span (XXXX.X meters) 5 digits

The length of the maximum span shall be recorded. It shall be noted 

whether the measurement is center to center of bearing points or clear 

open distance between piers, bents, or abutments. The measurement shall 

be along the centerline of the bridge. For this item, code a 5-digit 

number to represent the measurement to the nearest tenth of a meter 

(with an assumed decimal point).

EXAMPLES: Code

 Length of Maximum Span 35.5 meters 00355

 117.0 meters 01170

 1219.2 meters 12192

27
Item 49 - Structure Length (XXXXX.X meters) 6 digits

Record and code a 6-digit number to represent the length of the 

structure to the nearest tenth of a meter (with an assumed decimal 

point). This shall be the length of roadway which is supported on the 

bridge structure. The length should be measured back to back of 

backwalls of abutments or from paving notch to paving notch.

Culvert lengths should be measured along the center line of roadway 

regardless of their depth below grade. Measurement should be made 

between inside faces of exterior walls. Tunnel length should be 

measured along the centerline of the roadway. Be sure to code Item 5A = 

2 for all tunnels.

EXAMPLES: Code

 Structure Length 35.5 meters 000355

 542.1 meters 005421

 333.0 meters 003330

 10 123.5 meters 101235

(1) Item 49 - Structure Length

28
Item 49 - Structure Length (cont'd)

 Code

 (1) Item 49 - Structure Length = 5.7 m = 6.58 m 000066

 cos 30o 

29
Item 50 - Curb or Sidewalk Widths (XX.X meters, XX.X meters) 6 digits

Record and code two contiguous 3-digit numbers to represent the widths 

of the left and right curbs or sidewalks to nearest tenth of a meter 

(with assumed decimal points). This is a 6-digit number composed of 2 

segments, with the leftmost 3 digits representing the left curb or 

sidewalk and the rightmost 3 digits representing the right curb or 

sidewalk. "Left" and "Right" should be determined on the basis of 

direction of the inventory.

Segment Description Length

 50A Left curb or sidewalk width 3 digits

 50B Right curb or sidewalk width 3 digits

EXAMPLES: Left Side Right Side Code

 Curb or sidewalk None 2.3 meters 000023

 3.0 meters 4.1 meters 030041

 3.3 meters None 033000

 12.1 meters 11.5 meters 121115

 None None 000000

 0.6 meters 1.5 meters 006015

 (1) Item 51 - Bridge Roadway Width, Curb-to-Curb

 (2) Item 52 - Deck Width, Out-to-Out

 (3) Item 50 - Curb or Sidewalk Width

30
Item 50 - Curb or Sidewalk Widths (cont'd)

EXAMPLES:

 (1) Item 51 - Bridge Roadway Width, Curb-to-Curb

 (2) Item 52 - Deck Width, Out-to-Out

 (3) Item 50 - Curb or Sidewalk Width

31
Item 51 - Bridge Roadway Width, Curb-to-Curb (XXX.X meters) 4 digits

The information to be recorded is the most restrictive minimum distance 

between curbs or rails on the structure roadway. For structures with 

closed medians and usually for double decked structures, coded data will 

be the sum of the most restrictive minimum distances for all roadways 

carried by the structure*. The data recorded for this item must be 

compatible with other related route and bridge data (i.e., Items 28, 29, 

32, etc.). The measurement should be exclusive of flared areas for 

ramps. A 4-digit number should be used to represent the distance to the 

nearest tenth of a meter (with an assumed decimal point). See examples 

on pages 30 and 31.

Where traffic runs directly on the top slab (or wearing surface) of a 

culvert- type structure, e.g. an R/C box without fill, code the actual 

roadway width (curb-to-curb or rail-to-rail). This will also apply 

where the fill is minimal and headwalls or parapets affect the flow of 

traffic.

Where the roadway is on fill carried across a structure and the 

headwalls or parapets do not affect the flow of traffic, code 0000. 

This is considered proper inasmuch as a filled section simply maintains 

the roadway cross-section. However, for sidehill viaduct structures 

code the actual full curb-to-curb roadway width. See figure in the 

Commentary Appendix D. 

* Raised or non-mountable medians, open medians, and barrier widths 

are to be excluded from the summation along with barrier-protected 

bicycle and equestrian lanes.

EXAMPLES: Code

 Bridge Roadway Width 16.00 meters wide 0160

 21.43 meters wide 0214

 33.07 meters wide 0331

The last example above would be the coded value for the deck section 

shown below.

32
Item 52 - Deck Width, Out-to-Out (XXX.X meters) 4 digits

Record and code a 4-digit number to show the out-to-out width to the 

nearest tenth of a meter (with an assumed decimal point). If the 

structure is a through structure, the number to be coded will represent 

the lateral clearance between superstructure members. The measurement 

should be exclusive of flared areas for ramps. See examples on pages 30 

and 31.

Where traffic runs directly on the top slab (or wearing surface) of the 

culvert (e.g., an R/C box without fill) code the actual width 

(out-to-out). This will also apply where the fill is minimal and the 

culvert headwalls affect the flow of traffic. However, for sidehill 

viaduct structures code the actual out-to-out structure width. See 

figure in the Commentary Appendix D. 

Where the roadway is on a fill carried across a pipe or box culvert and 

the culvert headwalls do not affect the flow of traffic, code 0000. 

This is considered proper inasmuch as a filled section over a culvert 

simply maintains the roadway cross-section. 

Item 53 - Minimum Vertical Clearance Over Bridge Roadway 4 digits

 (XX.XX meters)

The information to be recorded for this item is the actual minimum 

vertical clearance over the bridge roadway, including shoulders, to any 

superstructure restriction, rounded down to the nearest hundredth of a 

meter. For double decked structures code the minimum, regardless 

whether it is pertaining to the top or bottom deck. When no 

superstructure restriction exists above the bridge roadway, or when a 

restriction is 30 meters or greater, code 9999. Coding of actual 

clearances between 30 meters and 99.99 meters to an exact measurement is 

optional. A 4-digit number should be coded to represent the clearance 

to the nearest hundredth of a meter (with an assumed decimal point).

EXAMPLES: Code

 Minimum Vertical Clearance

 No restriction 9999

 5.25 meters 0525

 23.00 meters 2300

 38.50 meters 9999

Item 54 - Minimum Vertical Underclearance 5 digits

 (X code, XX.XX meters)

Using a 1-digit code and a 4-digit number, record and code the minimum 

vertical clearance from the roadway (travel lanes only) or railroad 

track beneath the structure to the underside of the superstructure. 

(When both a railroad and highway are under the structure, code the most 

critical dimension.)

 Segment Description Length

 54A Reference feature 1 digit

 54B Minimum Vertical Underclearance 4 digits

33
Item 54 - Minimum Vertical Underclearance (cont'd)

Using one of the codes below, code in the first position, the reference 

feature from which the clearance measurement is taken:

 Code Description

 H Highway beneath structure

 R Railroad beneath structure

 N Feature not a highway or railroad

In the next 4 positions, code a 4-digit number to represent the minimum 

vertical clearance from that feature to the structure, truncated to the 

hundredth of a meter (with an assumed decimal point). When a restriction 

is 30 meters or greater, code 9999. Coding of actual clearances between 

30 meters and 99.99 meters to an exact measurement is optional. If the 

feature is not a highway or railroad, code the minimum vertical 

clearance 0000.

EXAMPLES: CODE

River beneath structure N0000

 Railroad 9.529 meters beneath structure R0952

Highway 10.464 meters beneath structure H1046

34
Item 55 - Minimum Lateral Underclearance on Right 4 digits

 (X code, XX.X meters)

Using a 1-digit code and a 3-digit number, record and code the minimum 

lateral underclearance on the right to the nearest tenth of a meter 

(with an assumed decimal point). When both a railroad and highway are 

under the structure, code the most critical dimension (Refer to Item 69 

- Underclearances, Horizontal - Table 3B).

 Segment Description Length

 55A Reference feature 1 digit

 55B Minimum Lateral Underclearance 3 digits

Using one of the codes below, code in the first position the reference 

feature from which the clearance measurement is taken:

 Code Description

 H Highway beneath structure

 R Railroad beneath structure

 N Feature not a highway or railroad

In the next 3 positions, code a 3-digit number to represent the minimum 

lateral underclearance on the right. The lateral clearance should be 

measured from the right edge of the roadway (excluding shoulders) or 

from the centerline (between rails) of the right-hand track of a 

railroad to the nearest substructure unit (pier, abutment, etc.), to a 

rigid barrier (concrete bridge rail, etc.), or to the toe of slope 

steeper than 1 to 3, e.g. 1 to 1 or 2 to 1. The clearance measurements 

to be recorded will be the minimum after measuring the clearance in both

directions of travel. In the case of a dual highway this would mean the 

outside clearances of both roadways should be measured and the smaller 

distance recorded and coded.

If two related features are below the bridge, measure both and record 

the lesser of the 2. An explanation should be written on the inspection 

form as to what was recorded. When the clearance is 30 meters or 

greater, code 999. Coding of actual clearances between 30 meters and 

99.9 meters to an exact measurement is optional.

If the feature beneath the structure is not a railroad or highway, code 

N000 to indicate not applicable.

The presence of ramps and acceleration or turning lanes is not 

considered in this item; therefore, the minimum lateral clearance on the 

right should be measured from the right edge of the through roadway.

EXAMPLES: Code

 

 Railroad 6.22 meters centerline to pier R062

 Highway 6.16 meters edge of pavement to pier H062

 Creek beneath structure N000

35
Item 55 – Minimum Lateral Underclearance on Right (cont’d)

EXAMPLES:

 36
Item 56 - Minimum Lateral Underclearance on Left 3 digits

 (XX.X meters) (code only for divided highways, 1-way

 streets, and ramps; not applicable to railroads)

Using a 3-digit number, record and code the minimum lateral underclearance on the left (median side for divided highways) to the nearest 

tenth of a meter (with an assumed decimal point). The lateral clearance 

should be measured from the left edge of the roadway (excluding shoulders) 

to the nearest substructure unit, to a rigid barrier, or to the toe of 

slope steeper than 1 to 3. Refer to examples on page 34 under Item 55 -

Minimum Lateral Underclearance on Right.

In the case of a dual highway, the median side clearances of both roadways 

should be measured and the smaller distance recorded and coded. If there 

is no obstruction in the median area, a notation of "open" should be 

recorded and 999 should be coded. For clearances greater than 30 meters, 

code 998. Coding of actual clearances greater than 30 meters to an exact 

measurement is optional. Code 000 to indicate not applicable.

Item 57

(Reserved)

Items 58 through 62 - Indicate the Condition Ratings

In order to promote uniformity between bridge inspectors, these guidelines 

will be used to rate and code Items 58, 59, 60, 61, and 62. The use of 

the AASHTO Guide for Commonly Recognized (CoRe) Structural Elements is an 

acceptable alternative to using these rating guidelines for Items 58, 59, 

60, and 62, provided the FHWA translator computer program is used to 

convert the inspection data to NBI condition ratings for NBI data 

submittal.

Condition ratings are used to describe the existing, in-place bridge as 

compared to the as-built condition. Evaluation is for the materials 

related, physical condition of the deck, superstructure, and substructure 

components of a bridge. The condition evaluation of channels and channel 

protection and culverts is also included. Condition codes are properly 

used when they provide an overall characterization of the general 

condition of the entire component being rated. Conversely, they are 

improperly used if they attempt to describe localized or nominally 

occurring instances of deterioration or disrepair. Correct assignment of 

a condition code must, therefore, consider both the severity of the 

deterioration or disrepair and the extent to which it is widespread 

throughout the component being rated.

The load-carrying capacity will not be used in evaluating condition items. 

 The fact that a bridge was designed for less than current legal loads and 

may be posted shall have no influence upon condition ratings.

Portions of bridges that are being supported or strengthened by temporary 

members will be rated based on their actual condition; that is, the 

temporary members are not considered in the rating of the

item. (See Item 103 - Temporary Structure Designation for the definition 

of a temporary bridge.)

Completed bridges not yet opened to traffic, if rated, shall be coded as 

if open to traffic

37

2000
Condition Ratings (cont'd)

The following general condition ratings shall be used as a guide in 

evaluating Items 58, 59, and 60:

Code Description

 N NOT APPLICABLE

 9 EXCELLENT CONDITION

 8 VERY GOOD CONDITION - no problems noted.

 7 GOOD CONDITION - some minor problems.

 6 SATISFACTORY CONDITION - structural elements show some minor 

deterioration.

 5 FAIR CONDITION - all primary structural elements are sound but 

may have minor section loss, cracking, spalling or scour.

 4 POOR CONDITION - advanced section loss, deterioration, spalling 

or scour.

 3 SERIOUS CONDITION - loss of section, deterioration, spalling or 

scour have seriously affected primary structural components. 

Local failures are possible. Fatigue cracks in steel or shear 

cracks in concrete may be present.

 2 CRITICAL CONDITION - advanced deterioration of primary structural 

 elements. Fatigue cracks in steel or shear cracks in 

concrete may be present or scour may have removed substructure 

support. Unless closely monitored it may be necessary to close 

the bridge until corrective action is taken.

 1 "IMMINENT" FAILURE CONDITION - major deterioration or section 

loss present in critical structural components or obvious 

vertical or horizontal movement affecting structure 

stability. Bridge is closed to traffic but corrective action 

may put back in light service.

 0 FAILED CONDITION - out of service - beyond corrective action.

Item 58 - Deck 1 digit

This item describes the overall condition rating of the deck. Rate and 

code the condition in accordance with the above general condition 

ratings. Code N for culverts and other structures without decks e.g., 

filled arch bridge. 

Concrete decks should be inspected for cracking, scaling, spalling, 

leaching, chloride contamination, potholing, delamination, and full or 

partial depth failures. Steel grid decks should be inspected for broken 

welds, broken grids, section loss, and growth of filled grids from 

corrosion. Timber decks should be inspected for splitting, crushing, 

fastener failure, and deterioration from rot.

The condition of the wearing surface/protective system, joints, 

expansion devices, curbs, sidewalks, parapets, fascias, bridge rail, and 

scuppers shall not be considered in the overall deck evaluation. 

However, their condition should be noted on the inspection form.

38
Item 58 - Deck (cont'd)

Decks integral with the superstructure will be rated as a deck only and 

not how they may influence the superstructure rating (for example, rigid 

frame, slab, deckgirder or T-beam, voided slab, box girder, etc.). 

Similarly, the superstructure of an integral deck-type bridge will not 

influence the deck rating.

Item 59 - Superstructure 1 digit

This item describes the physical condition of all structural members. 

Rate and code the condition in accordance with the previously described 

general condition ratings. Code N for all culverts.

The structural members should be inspected for signs of distress which 

may include cracking, deterioration, section loss, and malfunction and 

misalignment of bearings.

The condition of bearings, joints, paint system, etc. shall not be 

included in this rating, except in extreme situations, but should be 

noted on the inspection form.

On bridges where the deck is integral with the superstructure, the 

superstructure condition rating may be affected by the deck condition. 

The resultant superstructure condition rating may be lower than the deck 

condition rating where the girders have deteriorated or been damaged.

Fracture critical components should receive careful attention because 

failure could lead to collapse of a span or the bridge.

Item 60 - Substructure 1 digit

This item describes the physical condition of piers, abutments, piles, 

fenders, footings, or other components. Rate and code the condition in 

accordance with the previously described general condition ratings. 

Code N for all culverts.

All substructure elements should be inspected for visible signs of 

distress including evidence of cracking, section loss, settlement, 

misalignment, scour, collision damage, and corrosion. The rating given 

by Item 113 - Scour Critical Bridges, may have a significant effect on 

Item 60 if scour has substantially affected the overall condition of the 

substructure.

The substructure condition rating shall be made independent of the deck 

and superstructure.

Integral-abutment wingwalls to the first construction or expansion joint 

shall be included in the evaluation. For non-integral superstructure 

and substructure units, the substructure shall be considered as the 

portion below the bearings. For structures where the substructure and 

superstructure are integral, the substructure shall be considered as the 

portion below the superstructure.

39
Item 61 - Channel and Channel Protection 1 digit

This item describes the physical conditions associated with the flow of 

water through the bridge such as stream stability and the condition of the 

channel, riprap, slope protection, or stream control devices including 

spur dikes. The inspector should be particularly concerned with visible 

signs of excessive water velocity which may affect undermining of slope 

protection, erosion of banks, and realignment of the stream which may 

result in immediate or potential problems. Accumulation of drift and 

debris on the superstructure and substructure should be noted on the 

inspection form but not included in the condition rating.

Rate and code the condition in accordance with the previously described 

general condition ratings and the following descriptive codes:

Code Description

 N Not applicable. Use when bridge is not over a waterway (channel).

 9 There are no noticeable or noteworthy deficiencies which affect the 

condition of the channel.

 8 Banks are protected or well vegetated. River control devices such 

as spur dikes and embankment protection are not required or are in a 

stable condition.

 7 Bank protection is in need of minor repairs. River control devices 

and embankment protection have a little minor damage. Banks and/or 

channel have minor amounts of drift.

 6 Bank is beginning to slump. River control devices and embankment 

protection have widespread minor damage. There is minor stream bed 

movement evident. Debris is restricting the channel slightly.

 5 Bank protection is being eroded. River control devices and/or 

embankment have major damage. Trees and brush restrict the channel.

 4 Bank and embankment protection is severely undermined. River 

control devices have severe damage. Large deposits of debris are in 

the channel.

 3 Bank protection has failed. River control devices have been 

destroyed. Stream bed aggradation, degradation or lateral movement 

has changed the channel to now threaten the bridge and/or approach 

roadway.

 2 The channel has changed to the extent the bridge is near a state of 

collapse.

 1 Bridge closed because of channel failure. Corrective action may put 

back in light service.

 0 Bridge closed because of channel failure. Replacement necessary.

40
Item 62 - Culverts 1 digit

This item evaluates the alignment, settlement, joints, structural 

condition, scour, and other items associated with culverts. The rating 

code is intended to be an overall condition evaluation of the culvert. 

Integral wingwalls to the first construction or expansion joint shall be 

included in the evaluation. For a detailed discussion regarding the 

inspection and rating of culverts, consult Report No. FHWA-IP-86-2, 

Culvert Inspection Manual, July 1986.

Item 58 - Deck, Item 59 - Superstructure, and Item 60 - Substructure 

shall be coded N for all culverts.

Rate and code the condition in accordance with the previously described 

general condition ratings and the following descriptive codes:

Code Description

 N Not applicable. Use if structure is not a culvert.

 9 No deficiencies.

 8 No noticeable or noteworthy deficiencies which affect the 

condition of the culvert. Insignificant scrape marks caused by 

drift.

 7 Shrinkage cracks, light scaling, and insignificant spalling which 

does not expose reinforcing steel. Insignificant damage caused

by drift with no misalignment and not requiring corrective 

action. Some minor scouring has occurred near curtain walls, 

wingwalls, or pipes. Metal culverts have a smooth symmetrical 

curvature with superficial corrosion and no pitting.

 6 Deterioration or initial disintegration, minor chloride 

contamination, cracking with some leaching, or spalls on concrete 

or masonry walls and slabs. Local minor scouring at curtain 

walls, wingwalls, or pipes. Metal culverts have a smooth 

curvature, non-symmetrical shape, significant corrosion or 

moderate pitting.

 5 Moderate to major deterioration or disintegration, extensive 

cracking and leaching, or spalls on concrete or masonry walls and 

slabs. Minor settlement or misalignment. Noticeable scouring or 

erosion at curtain walls, wingwalls, or pipes. Metal culverts 

have significant distortion and deflection in one section, 

significant corrosion or deep pitting.

 4 Large spalls, heavy scaling, wide cracks, considerable 

efflorescence, or opened construction joint permitting loss of 

backfill. Considerable settlement or misalignment. Considerable 

scouring or erosion at curtain walls, wingwalls or pipes. Metal 

culverts have significant distortion and deflection throughout, 

extensive corrosion or deep pitting.

(codes continued on the next page)

41
Item 62 - Culverts (cont'd)

 3 Any condition described in Code 4 but which is excessive in 

scope. Severe movement or differential settlement of the 

segments, or loss of fill. Holes may exist in walls or slabs. 

Integral wingwalls nearly severed from culvert. Severe scour or 

erosion at curtain walls, wingwalls or pipes. Metal culverts 

have extreme distortion and deflection in one section, extensive 

corrosion, or deep pitting with scattered perforations.

 2 Integral wingwalls collapsed, severe settlement of roadway due to 

loss of fill. Section of culvert may have failed and can no 

longer support embankment. Complete undermining at curtain walls 

and pipes. Corrective action required to maintain traffic. 

Metal culverts have extreme distortion and deflection throughout 

with extensive perforations due to corrosion.

 1 Bridge closed. Corrective action may put back in light service.

 0 Bridge closed. Replacement necessary.

Item 63 - Method Used to Determine Operating Rating 1 digit

Use one of the codes below to indicate which load rating method was used 

to determine the Operating Rating coded in Item 64 for this structure.

 Code Description

 1 Load Factor (LF) 

 2 Allowable Stress (AS)

 3 Load and Resistance Factor (LRFR)

 4 Load Testing

 5 No rating analysis performed

42
Item 64 - Operating Rating (XX.X metric tons) 3 digits

This capacity rating, referred to as the operating rating, will result 

in the absolute maximum permissible load level to which the structure 

may be subjected for the vehicle type used in the rating. Code the 

operating rating as a 3-digit number to represent the total mass in 

metric tons of the entire vehicle measured to the nearest tenth of a 

metric ton (with an assumed decimal point).

It should be emphasized that only MS loading shall be used to determine 

the operating rating. This is the metric equivalent of an HS loading. 

The total mass in tons of the entire vehicle should be coded; that is, 

MS18 which has a mass of 32.4 metric tons shall be coded '324', and 

likewise, a MS13.5 shall be coded '243'.

The AASHTO Manual for Condition Evaluation of Bridges provides a choice 

of load rating methods, such as the new load and resistance factor 

(LRFR) rating method, in addition to the traditional allowable stress 

(AS) and load factor (LF) methods. Of the three rating methods, the LF 

method is the most suitable for use as a national standard, therefore 

the FHWA has chosen the LF method as the standard for computing 

inventory and operating ratings reported to the NBI. The highway 

agencies may, however, elect to use LF, AS or LRFD to establish load 

limits for purposes of load posting.

If the bridge will not carry a minimum of 2.7 metric tons of live load, 

the operating rating shall be coded '000'; and consistent with the 

direction of the AASHTO Manual, it shall be closed.

The use or presence of a temporary bridge requires special consideration 

in coding. In such cases, since there is no permanent bridge, Items 64 

and 66 should be coded as 000 even though the temporary structure is 

rated for as much as full legal load.

A bridge shored up or repaired on a temporary basis is considered a 

temporary bridge and the inventory and operating rating shall be coded 

as if the temporary shoring were not in place. See Item 103 - Temporary 

Structure Designation for definition of a temporary bridge.

Code 999 for a structure under sufficient fill such that, according to 

AASHTO design, the live load is insignificant in the structure load 

capacity.

EXAMPLES: Code

 MS27 486

 Temporary bridge 000

 Shored-up bridge 030*

 Structure under fill (not affected by live load) 999

* load capacity without shoring.

43
Item 65 - Method Used to Determine Inventory Rating 1 digit

Use one of the codes below to indicate which load rating method was used 

to determine the Inventory Rating coded in Item 66 for this structure.

 Code Description

 1 Load Factor (LF) 

 2 Allowable Stress (AS)

 3 Load and Resistance Factor (LRFR)

 4 Load Testing

 5 No rating analysis performed

Item 66 - Inventory Rating (XX.X metric tons) 3 digits

This capacity rating, referred to as the inventory rating, will result 

in a load level which can safely utilize an existing structure for an

indefinite period of time. Only the MS loading shall be used to 

determine the inventory rating. Code the Inventory Rating as a 3-digit 

number to represent the total mass in metric tons of the entire vehicle 

measured to the nearest tenth of a metric ton (with an assumed decimal 

point). The statements in Item 64 - Operating Rating apply to this item 

also.

Code 999 for a structure under sufficient fill such that, according to 

AASHTO design, the live load is insignificant in the structure load 

capacity.

44
Items 67, 68, 69, 71, and 72 - Indicate the Appraisal Ratings

The items in the Appraisal Section are used to evaluate a bridge in 

relation to the level of service which it provides on the highway system 

of which it is a part. The structure will be compared to a new one 

which is built to current standards for that particular type of road as 

further defined in this section except for Item 72 - Approach Roadway 

Alignment. See Item 72 for special criteria for rating that item.

Items 67, 68, 69, 71, and 72 will be coded with a 1-digit code that 

indicates the appraisal rating for the item. The ratings and codes are 

as follows:

Code Description

 N Not applicable

 9 Superior to present desirable criteria

 8 Equal to present desirable criteria

 7 Better than present minimum criteria

 6 Equal to present minimum criteria

 5 Somewhat better than minimum adequacy to tolerate being

 left in place as is

 4 Meets minimum tolerable limits to be left in place as is

 3 Basically intolerable requiring high priority of corrective

 action

 2 Basically intolerable requiring high priority of

 replacement

 1 This value of rating code not used

 0 Bridge closed

The FHWA Edit/Update computer program calculates values for Items 67, 68 

and 69 according to the tables provided in this manual. These tables 

and the table for Item 71 shall be used by all evaluators to rate these 

items. They have been developed to closely match the descriptions for 

the appraisal evaluation codes of 0 to 9. The tables shall be used in 

all instances to evaluate the item based on the designated data in the 

inventory, even if a table value does not appear to match the 

descriptive codes. For unusual cases where the site data does not 

exactly agree with the table criteria, use the most appropriate table to 

evaluate the item. The code of N is not valid for use with Items 67 and 

72.

Completed bridges not yet opened to traffic, if rated, shall be 

appraised as if open to traffic. Design values, for example ADT, shall 

be used for the evaluation. The data provided will include a code of G 

for Item 41 - Structure Open, Posted, or Closed to Traffic.

45
Item 67 - Structural Evaluation 1 digit

This item is calculated by the Edit/Update Program based on Table 1, and 

need not be coded by the bridge inspector. The following specifications 

are used by the Edit/Update Program:

! For structures other than culverts, the lowest of the codes obtained 

from Item 59 - Superstructure, Item 60 - Substructure, or Table 1 is 

used.

! For culverts, the lowest of the codes obtained from Item 62 -

Culverts, or Table 1 is used.

! If Item 59, Item 60 or Item 62 is coded 1, then Item 67 is equal to 

zero (0), regardless of whether the structure is actually closed. 

However, if the structure is closed, it does not mean that this 

value is zero (0) unless the overall condition and appraisal ratings 

indicate that a code of 0 is appropriate.

Table 1 Notes:

1. Use the lower rating code for values between those listed in the 

table.

2. Inventory Ratings are shown in metric tons with decimal point.

3. To use Table 1, the Inventory Rating must be the coded MS rating or 

its equivalent. If the comparable MS equivalent is not calculated 

for the controlling rating, using a factor to determine the MS 

equivalent is acceptable even though converting other rating loads 

to an MS equivalent is not a constant.

4. All bridges with Item 26 - Functional Class coded Interstate, 

Freeway or Expressway shall be evaluated using the ADT column of 

>5000 regardless of the actual ADT on the bridge.

46
Item 67 - Structural Evaluation (cont'd)

 Table 1. Rating by Comparison of ADT - Item 29

 and Inventory Rating - Item 66

 

 

Inventory Rating

Average Daily Traffic (ADT)

Structural

Evaluation

Rating

Code 0-500 501-5000 >5000

9 >32.4

(MS18)*

>32.4

(MS18)

>32.4

(MS18)

8 32.4

(MS18)

32.4

(MS18)

32.4

(MS18)

7 27.9

(MS15.5)

27.9

(MS15.5)

27.9

(MS15.5)

6 20.7

(MS11.5)

22.5

(MS12.5)

24.3

(MS13.5)

5 16.2

(MS9)

18.0

(MS10)

19.8

(MS11)

4 10.8

(MS6)

12.6

(MS7)

16.2

(MS9)

3 Inventory rating less than value in rating

code of 4 and requiring corrective action.

2 Inventory rating less than value in rating

 code of 4 and requiring replacement.

0 Bridge closed due to structural condition.

*MS Designation (typical)

47
Item 68 - Deck Geometry 1 digit

This item is calculated by the Edit/Update Program and need not be coded 

by the bridge inspector.

The overall rating for deck geometry includes two evaluations: (a) the 

curb-to-curb or face-to-face of rail bridge width using Table 2A, B, C 

or D and (b) the minimum vertical clearance over the bridge roadway 

using Table 2E. The lower of the codes obtained from these tables is 

used by the Edit/Update Program. When an individual table lists several 

deck geometry rating codes for the same roadway width under a specific 

ADT, the lower code is used. (For example, Table 2A lists deck geometry 

rating codes of 6, 7 and 8 for a 13.4 meter roadway width and an ADT of 

>5000. Use the code of 6.) For values between those listed in the 

tables, the lower code is used.

The curb-to-curb or face-to-face of rail dimension shall be taken from 

Item 51 - Bridge Roadway Width, Curb-to-curb. Item 53 - Minimum 

Vertical Clearance Over Bridge Roadway is used to evaluate the vertical 

clearance.

For culverts which have Item 51 - Bridge Roadway Width coded 0000, the 

Deck Geometry code will be equal to N.

The values provided in the tables are for rating purposes only. Current 

design standards must be used for structure design or rehabilitation.

48
Item 68 - Deck Geometry (cont'd)

 Table 2A & 2B. Rating by Comparison of ADT - Item 29 and

 Bridge Roadway Width, Curb-to-Curb - Item 51

TABLE 2A TABLE 2B

Bridge Roadway Width

2 Lanes; 2 Way Traffic

Bridge Roadway 

Width

1 Lane; 2-Way 

Traffic

ADT (Both Directions) ADT (Both 

Directions)

Deck

Geometry

Rating

Code

0-100 101-

400

401-

1000

1001-

2000

2001-

5000

>5000 0-100 >100

9 >9.8 >11.0 >12.2 >13.4 >13.4 >13.4 - -

8 9.8 11.0 12.2 13.4 13.4 13.4 <4.9 -

7 8.5 9.8 11.0 12.2 13.4 13.4 4.6 -

6 7.3 8.5 9.1 10.4 12.2 13.4 4.3 -

5 6.1 7.3 7.9 8.5 10.4 11.6 4.0 -

4 5.5 6.1 6.7 7.3 8.5 9.8

(8.5)*

3.7 -

3 4.9 5.5 6.1 6.7 7.9 9.1

(7.9)*

3.4 <4.9

2 Any width less than required for a rating code of 3 and structure 

is open.

0 Bridge Closed

 * Use value in parentheses for bridges longer than 60 meters.

 Notes:

 1. Use the lower rating code for values between those listed

in the table.

 2. Dimensions are in meters.

 3. For 1 lane of one-way traffic Table 2A is used.

 4. For 3 or more undivided lanes of 2-way traffic, use Table 2C,

Other Multilane Divided Facilities.

 5. Do not use Table 2B for code 9 and for codes 8 through 4

inclusive when the ADT >100. Single lane bridges less than

4.9 meters wide carrying 2-way traffic are always appraised

at 3 or below if they carry more than an ADT of 100.

 6. One-lane bridges 4.90 meters and greater in roadway width, which are not 

ramps, are evaluated as a 2-lane bridge using Table 2A.

49
Item 68 - Deck Geometry (cont'd)

 Table 2C & 2D. Rating by Comparison of Number of Lanes - Item 28

 and Bridge Roadway Width, Curb-to-Curb - Item 51

TABLE 2C TABLE 2D

Bridge Roadway Width

2 or More Lanes

Bridge Roadway Width

1-Way Traffic

Interstate and Other

Divided Freeways

Other Multilane

Divided Facilities

Ramps Only

(Item 5C = 7)

Deck

Geometry

Rating

Code

2 Lanes

1-way

3 or more

Lanes

2 Lanes

1-way

3 or more

Lanes

1 Lane 2 or more

Lanes

9 >12.8 >3.7N+7.3 >12.8 >3.7N+5.5 >7.9 >3.7N+3.7

8 12.8 3.7N+7.3 12.8 3.7N+5.5 7.9 3.7N+3.7

7 12.2 3.7N+6.1 11.6 3.7N+4.6 7.3 3.7N+3.0

6 11.6 3.7N+4.9 11.0 3.7N+3.7 6.7 3.7N+2.4

5 11.0 3.7N+4.3 10.1 3.4N+3.0 6.1 3.7N+1.8

4

4

10.4

(8.8)*

3.4N+3.7

(3.4N+2.1)

*

9.1

9.1

3.4N+1.8

3.4N+1.8

5.5

5.5

3.7N+1.2

3.7N+1.2

3

3

10.1

(8.5)*

3.4N+3.4

(3.4N+1.8)

*

8.2

8.2

3.4N+1.5

3.4N+1.5

4.9

4.9

3.7N+0.6

3.7N+0.6

2 Any width less than required for a rating code of 3 and 

structure is open.

0 Bridge Closed

 * Use value in parentheses for bridges longer than 60 meters.

 N = Total number of lanes of traffic on the structure.

 Notes

 1. Use the lower rating code for values between those listed

in the tables.

 2. Dimensions are in meters.

 3. Use Table 2C, Other Multilane Divided Facilities, for 3 or more

undivided lanes of 2-way traffic.

50
Item 68 - Deck Geometry (cont'd)

 Table 2E. Rating by Comparison of Minimum Vertical Clearance over

 Bridge Roadway - Item 53 and Functional Classification - Item 26

 

Minimum Vertical Clearance

Functional Class

Deck

Geometry

Rating

Code Interstate

and Other

Freeway

Other 

Principal

and Minor

Arterial

Major and

Minor

Collectors

and Locals

9 >5.18 >5.02 >5.02

8 5.18 5.02 5.02

7 5.10 4.72 4.72

6 5.02 4.41 4.41

5 4.80 4.34 4.34

4 4.57 4.26 4.26

3 Vertical clearance less than value in rating

code of 4 and requiring corrective action.

2 Vertical clearance less than value in rating

code of 4 and requiring replacement.

0 Bridge Closed.

 Notes

 1. Use the lower rating code for values between those

 listed in the table.

 2. Dimensions are in meters.

51
Item 69 - Underclearances, Vertical and Horizontal 1 digit

This item is calculated by the Edit/Update Program and need not be coded 

by the bridge inspector.

Vertical and horizontal underclearances are measured from the through 

roadway to the superstructure or substructure units, respectively. Code 

"N" is used unless the bridge is over a highway or railroad.

The vertical underclearance is evaluated using Table 3A. The horizontal 

underclearance is evaluated using Table 3B. The lower of the codes 

obtained from Table 3A and Table 3B is used by the Edit/Update Program.

Bridges seldom are closed due to deficient underclearances, however, 

these bridges may be good candidates for rehabilitation or replacement.

Item 54 - Minimum Vertical Underclearance, Item 55 - Minimum Lateral 

Underclearance on Right, and Item 56 - Minimum Lateral Underclearance on 

Left are used to evaluate this item.

The functional classification used in the table is for the underpassing 

route. Therefore, the functional classification is obtained from the 

record for the route "under" the bridge (see Item 5 - Inventory Route).

If the underpassing route is not on a Federal-aid system, is not a 

defense route, or is not otherwise important, an "under" record may not 

be available. If no "under" record exits, it is assumed that the route 

under the bridge is a major or minor collector or a local road for the 

purpose of using Tables 3A and 3B.

52
Item 69 - Underclearances, Vertical and Horizontal (cont'd)

Table 3A. Rating by Comparison of Minimum Vertical Underclearance -

Item 54 and Functional Classification of Underpassing Route - Item 26 

 

Minimum Vertical Underclearance

Functional Class

Underclearance

Rating

Code Interstate

and Other 

Freeway

Other 

Principal

and Minor

Arterial

Major and

minor

Collectors

and Locals

Railroad

9 >5.18 >5.02 >5.02 >7.01

8 5.18 5.02 5.02 7.01

7 5.10 4.72 4.72 6.85

6 5.02 4.41 4.41 6.70

5 4.80 4.34 4.34 6.40

4 4.57 4.26 4.26 6.09

3 Underclearance less than value in rating code of 4

and requiring corrective action.

2 Underclearance less than value in rating code of 4

and requiring replacement.

0 Bridge closed.

 Notes

 1. Use the lower rating code for values between those listed

 in the tables.

 2. Dimensions are in meters.

 3. The functional classification of the underpassing route shall

 be used in the evaluation. If an "under" record is not coded,

 the underpassing route shall be considered a major or minor

 collector or a local road.

53
Item 69 - Underclearances, Vertical and Horizontal (cont'd)

 Table 3B. Rating by Comparison of Minimum Lateral

 Underclearances Right & Left - Items 55 & 56 and

 Functional Classification of Underpassing Route - Item 26

Minimum Lateral Underclearance

Functional Class

1-Way Traffic 2-Way Traffic

Principal ArterialInterstate, Freeways

or Expressways

Main Line Ramp

Underclearance

Rating

Code

Left Right Left Right

Other 

Principal

and Minor 

Arterial

Major and

Minor

Collectors

and Locals

Railroad

9 >9.1 >9.1 >1.2 >3.0 >9.1 >3.7 >6.1

8 9.1 9.1 1.2 3.0 9.1 3.7 6.1

7 5.5 6.4 0.9 2.7 6.4 3.4 5.2

6 1.8 3.7 0.6 2.4 3.7 3.0 4.3

5 1.5 3.4 0.6 1.8 3.0 2.4 3.4

4 1.2 3.0 0.6 1.2 1.8 1.2 2.4

3 Underclearance less than value in rating code of 4

and requiring corrective action.

2 Underclearance less than value in rating code of 4

and requiring replacement.

0 Bridge closed.

 Notes:

 1. Use the lower rating code for values between those listed

 in the tables.

 2. Dimensions are in meters.

 3. When acceleration or deceleration lanes or ramps are provided

 under 2-way traffic, use the value from the right ramp column

 to determine code.

 4. The functional classification of the underpassing route shall

 be used in the evaluation. If an "under" record is not

 coded, the underpassing route shall be considered a major or

 minor collector or a local road.

54
Item 70 - Bridge Posting 1 digit

The National Bridge Inspection Standards require the posting of load 

limits only if the maximum legal load configurations in the State 

exceeds the load permitted under the operating rating. If the load 

capacity at the operating rating is such that posting is required, this 

item shall be coded 4 or less. If no posting is required at the 

operating rating, this item shall be coded 5.

This item evaluates the load capacity of a bridge in comparison to the 

State legal load. It differs from Item 67 - Structural Evaluation in 

that Item 67 uses Item 66 - Inventory Rating, while the bridge posting 

requirement is based on Item 64 - Operating Rating.

Although posting a bridge for load-carrying capacity is required only 

when the maximum legal load exceeds the operating rating, highway 

agencies may choose to post at a lower level. This posting practice may 

appear to produce conflicting coding when Item 41 - Structure Open, 

Posted or Closed to Traffic is coded to show the bridge as actually 

posted at the site and Item 70 - Bridge Posting is coded as bridge 

posting is not required. Since different criteria are used for coding 

these 2 items, this coding is acceptable and correct when the highway 

agency elects to post at less than the operating rating. Item 70 shall 

be coded 4 or less only if the legal load of the State exceeds that 

permitted under the operating rating.

The use or presence of a temporary bridge affects the coding. The 

actual operating rating of the temporary bridge should be used to 

determine this item. However the highway agency may choose to post at a 

lower level. This also applies to bridges shored up or repaired on a 

temporary basis.

Code Description

4 or less Posting required

5 No posting required

The degree that the operating rating is less than the maximum legal load 

level may be used to differentiate between codes. As a guide and for 

coding purposes only, the following values may be used to code this 

item:

Code Relationship of Operating Rating

 to Maximum Legal Load

5 Equal to or above legal loads

4 0.1 - 9.9% below

3 10.0 - 19.9% below

2 20.0 - 29.9% below

1 30.0 - 39.9% below

0 > 39.9% below

55
Item 71 - Waterway Adequacy 1 digit

This item appraises the waterway opening with respect to passage of flow 

through the bridge. The following codes shall be used in evaluating 

waterway adequacy (interpolate where appropriate). Site conditions may 

warrant somewhat higher or lower ratings than indicated by the table 

(e.g., flooding of an urban area due to a restricted bridge opening).

Where overtopping frequency information is available, the descriptions 

given in the table for chance of overtopping mean the following:

 Remote - greater than 100 years

 Slight - 11 to 100 years

 Occasional - 3 to 10 years

 Frequent - less than 3 years

Adjectives describing traffic delays mean the following:

 Insignificant - Minor inconvenience. Highway passable in a

 matter of hours.

 Significant - Traffic delays of up to several days.

 Severe - Long term delays to traffic with resulting

 hardship.

 

Functional Classification 

 Other

Principal Principal

Arterials - and Minor Description

Interstates, Arterials Minor

Freeways, or and Major Collectors,

Expressways Collectors Locals Code 

 

N N N Bridge not over a waterway.

9 9 9 Bridge deck and roadway approaches 

above flood water elevations (high 

water). Chance of overtopping is 

remote.

8 8 8 Bridge deck above roadway 

approaches. Slight chance of 

overtopping roadway approaches.

6 6 7 Slight chance of overtopping 

bridge deck and roadway 

approaches.

4 5 6 Bridge deck above roadway 

approaches. Occasional 

overtopping of roadway approaches 

with insignificant traffic delays.

(codes continued on the next page)

56
Item 71 - Waterway Adequacy (cont'd)

 

Functional Classification 

 Other

Principal Principal

Arterials - and Minor Description

Interstates, Arterials Minor

Freeways, or and Major Collectors,

Expressways Collectors Locals Code 

 

3 4 5 Bridge deck above roadway 

 approaches. Occasional 

overtopping of roadway approaches 

with significant traffic delays.

2 3 4 Occasional overtopping of bridge 

 deck and roadway approaches with 

 significant traffic delays.

2 2 3 Frequent overtopping of bridge 

deck and roadway approaches with 

 significant traffic delays.

2 2 2 Occasional or frequent overtopping 

of bridge deck and roadway 

approaches with severe traffic 

delays.

0 0 0 Bridge closed.

Item 72 - Approach Roadway Alignment 1 digit

Code the rating based on the adequacy of the approach roadway alignment. 

This item identifies those bridges which do not function properly or 

adequately due to the alignment of the approaches. It is not intended 

that the approach roadway alignment be compared to current standards but 

rather to the existing highway alignment. This concept differs from other 

appraisal evaluations. The establishment of set criteria to be used at 

all bridge sites is not appropriate for this item. The basic criteria is 

how the alignment of the roadway approaches to the bridge relate to the 

general highway alignment for the section of highway the bridge is on.

The individual structure shall be rated in accordance with the general 

appraisal rating guide described on page 453 in lieu of specific design 

values. The approach roadway alignment will be rated intolerable (a code 

of 3 or less) only if the horizontal or vertical curvature requires a 

substantial reduction in the vehicle operating speed from that on the 

highway section. A very minor speed reduction will be rated a 6, and when 

a speed reduction is not required, the appraisal code will be an 8. 

Additional codes may be selected between these general values.

57
Item 72 - Approach Roadway Alignment (cont'd)

For example, if the highway section requires a substantial speed 

reduction due to vertical or horizontal alignment, and the roadway 

approach to the bridge requires only a very minor additional speed 

reduction at the bridge, the appropriate code would be a 6. This 

concept shall be used at each bridge site.

Speed reductions necessary because of structure width and not alignment 

shall not be considered in evaluating this item.

Item 73 and Item 74

(Reserved)

Item 75 - Type of Work 3 digits

The information to be recorded for this item will be the type of work 

proposed to be accomplished on the structure to improve it to the point 

that it will provide the type of service needed and whether the proposed 

work is to be done by contract or force account. Code a 3-digit number 

composed of 2 segments.

 Segment Description Length

 75A Type of Work Proposed 2 digits

 75B Work Done by 1 digit

This item must be coded for bridges eligible for the Highway Bridge 

Replacement and Rehabilitation Program. To be eligible, a bridge must 

carry highway traffic, be deficient and have a sufficiency rating of 

80.0 or less. This item may be coded for other bridges at the option of 

the highway agency. Use one of the following codes to represent the 

proposed work type, otherwise leave blank:

 Code Description

 31 Replacement of bridge or other structure 

because of substandard load carrying capacity 

or substandard bridge roadway geometry.

 32 Replacement of bridge or other structure 

because of relocation of road.

 33 Widening of existing bridge or other major 

structure without deck rehabilitation or 

replacement; includes culvert lengthening.

 34 Widening of existing bridge with deck 

rehabilitation or replacement.

(codes continued on the next page)

58
Item 75 - Type of Work (cont'd)

 35 Bridge rehabilitation because of general 

structure deterioration or inadequate 

strength.

 36 Bridge deck rehabilitation with only 

incidental widening.

 37 Bridge deck replacement with only incidental 

widening.

 38 Other structural work, including hydraulic 

replacements.

If segment A is blank, leave segment B blank. Otherwise, the third 

digit shall be coded using one of the following codes to indicate 

whether the proposed work is to be done by contract or by force account:

 Code Description

 1 Work to be done by contract

 2 Work to be done by owner's forces

EXAMPLES: Code

 A bridge is to be replaced by contract because it has 311

 deteriorated to the point that it can no longer carry legal 

 loads. The same code should be used if the bridge is 

 replaced because it is now too narrow or the original design

 was too light to accommodate today's legal loads.

A bridge is to be replaced because the roadway must be 321

 straightened to eliminate a dangerous curve. The work will 

 be done by contract.

A bridge is to be widened to increase shoulder width or 331

 the number of traffic lanes. The existing deck is in good

 condition and will be incorporated as is into the new 

 structure. The work is to be done by contract.

A culvert is to be extended by contract to accommodate 331

 additional roadway width as part of a reconstruction 

 contract to improve the safety of the adjacent slopes.

A deck is to be rehabilitated and the bridge widened 341

 to provide a full 3.6 meter shoulder. The existing 

 shoulder is only .2 meters wide and an extra line of 

 girders with appropriate substructure widening must be 

 added. The work will be done by contract.

A bridge superstructure and substructure are to be 352

 rehabilitated by State forces to increase the bridge's 

 load capacity.

59
Item 75 - Type of Work (cont'd)

EXAMPLES: Code

A bridge deck is to be rehabilitated by contract and a 361

 safety curb to be removed which results in incidental 

 widening of 0.6 meters.

A bridge deck is to be replaced by contract and the 371

 deck cantilever overhang extended 0.6 meters, which is 

 the maximum that can be done without adding another line 

 of stringers or girders to the superstructure.

A bridge which is no longer needed is to be demolished 382

 and an at-grade crossing built by State forces. (This 

 code could also be used to designate incidental safety 

 work on a bridge such as bridge-rail upgrading or 

 replacement.)

Item 76 - Length of Structure Improvement (XXXXX.X meters) 6 digits

Code a 6-digit number that represents the length of the proposed bridge 

improvement to the nearest tenth of a meter (with an assumed decimal 

point). For replacement or rehabilitation of the entire bridge, the 

length should be back to back of backwalls of abutments or from pavement 

notch to pavement notch. For replacement or rehabilitation of only part 

of the structure, use the length of the portion to be improved.

This item must be coded for bridges eligible for the Highway Bridge 

Replacement and Rehabilitation Program. It may be coded for other 

bridges at the option of the highway agency.

For culvert improvements, use the proposed length measured along the 

centerline of the barrel regardless of the depth below grade. The 

measurement should be made between the inside faces of the top parapet 

or edge-stiffening beam of the top slab.

EXAMPLES: Code

 Length of Structure Improvement 76.2 meters 000762

 1200 meters 012000

 12,345 meters 123450

For substructure or channel work only, code the length of superstructure 

over, or supported by, the substructure or channel.

Typically, a replacement bridge is longer than the existing bridge. 

Nationwide averages for the increase in bridge length with replacement 

as a function of the existing length are given in the following figures. 

 The length-expansion factors represent data for the years 1981 to 1985. 

 Where site-specific data is lacking, these factors are suggested for 

estimating the length of replacement bridges. For exceedingly long 

bridges (i.e., 300 meters or more) the length-expansion factor 

approaches 1.0.

60
Item 76 - Length of Structure Improvement (cont'd)

INCREASED LENGTH OF REPLACEMENT BRIDGES

 X = EXISTING BRIDGE LENGTH 

 Y = LENGTH EXPANSION FACTOR

REPLACEMENT BRIDGE LENGTH = EXISTING BRIDGE LENGTH x LENGTH EXPANSION 

FACTOR

61
Item 77 through Item 89

(Reserved)

Item 90 - Inspection Date 4 digits

Record the month and year that the last routine inspection of the 

structure was performed. This inspection date may be different from 

those recorded in Item 93 - Critical Feature Inspection Date. Code a 

4-digit number to represent the month and year. The number of the month 

should be coded in the first 2 digits with a leading zero as required 

and the last 2 digits of the year coded as the third and fourth digits 

of the field.

EXAMPLES: Code

 Inspection date November 1992 1192

 March 1994 0394

Item 91 - Designated Inspection Frequency 2 digits

Code 2 digits to represent the number of months between designated 

inspections of the structure. A leading zero shall be coded as 

required. This interval is usually determined by the individual in 

charge of the inspection program. For posted, understrength bridges, 

this interval should be substantially less than the 24-month standard. 

The designated inspection interval could vary from inspection to 

inspection depending on the condition of the bridge at the time of 

inspection.

EXAMPLES: Code

 Posted bridge with heavy truck traffic 01

 and questionable structural details

 which is designated to be inspected

 each month

 Bridge is scheduled to be inspected 24

 every 24 months

It should be noted that bridges will also require special non-scheduled 

inspections after unusual physical traumas such as floods, earthquakes, 

fires or collisions. These special inspections may range from a very 

brief visual examination to a detailed in-depth evaluation depending 

upon the nature of the trauma. For example, when a substructure pier or 

abutment is struck by an errant vehicle, in most cases only a visual 

examination of the bridge is necessary. After major collisions or 

earthquakes, in-depth inspections may be warranted as directed by the 

engineer in overall charge of the program. After and during severe 

floods, the stability of the substructure of bridges may have to be 

determined by probing, underwater sensors or other appropriate measures. 

 Underwater inspection by divers may be required for some scour critical 

bridges immediately after floods. See Item 113 - Scour Critical 

Bridges.

62
Item 92 - Critical Feature Inspection 9 digits

Using a series of 3-digit code segments, denote critical features that 

need special inspections or special emphasis during inspections and the 

designated inspection interval in months as determined by the 

individual in charge of the inspection program. The designated 

inspection interval could vary from inspection to inspection depending 

on the condition of the bridge at the time of inspection.

 Segment Description Length

 92A Fracture Critical Details 3 digits

 92B Underwater Inspection 3 digits

 92C Other Special Inspection 3 digits

For each segment of Item 92A, B, and C, code the first digit Y for 

special inspection or emphasis needed and code N for not needed. The 

first digit of Item 92A, B, and C must be coded for all structures to 

designate either a yes or no answer. Those bridges coded with a Y in 

Item 92A or B should be the same bridges contained in the Master Lists 

of fracture critical and special underwater inspection bridges. In the 

second and third digits of each segment, code a 2-digit number to 

indicate the number of months between inspections only if the first 

digit is coded Y. If the first digit is coded N, the second and third 

digits are left blank.

Current guidelines for the maximum allowable interval between 

inspections can be summarized as follows:

Fracture Critical Details 24 months

Underwater Inspection 60 months

Other Special Inspections 60 months

EXAMPLES: Item Code

A 2-girder system structure which is being 92A Y12

inspected yearly and no other special inspections 92B N__

are required. 92C N__

A structure where both fracture critical and 92A Y12

underwater inspection are being performed on a 92B Y12

1-year interval. Other special inspections 92C N__

are not required.

A structure has been temporarily shored and is 92A N__

being inspected on a 6-month interval. Other 92B N__

special inspections are not required. 92C Y06

63

2000
Item 93 - Critical Feature Inspection Date 12 digits

Code only if the first digit of Item 92A, B, or C is coded Y for yes. 

Record as a series of 4-digit code segments, the month and year that the 

last inspection of the denoted critical feature was performed.

 Segment Description Length

 93A Fracture Critical Details 4 digits

 93B Underwater Inspection 4 digits

 93C Other Special Inspection 4 digits

For each segment of this item, when applicable, code a 4-digit number to 

represent the month and year. The number of the month should be coded 

in the first 2 digits with a leading zero as required and the last 2 

digits of the year coded as the third and fourth digits of the field. 

If the first digit of any part of Item 92 is coded N, then the 

corresponding part of this item shall be blank.

EXAMPLES: Item Code

A structure has fracture critical members which 93A 0386

were last inspected in March 1986. It does not 93B (blank)

require underwater or other special feature 93C (blank)

inspections.

A structure has no fracture critical details, but 93A (blank)

requires underwater inspection and has other special 93B 0486

features (for example, a temporary support) for which 93C 1185

the State requires special inspection. The last

underwater inspection was done in April 1986 and the

last special feature inspection was done in November 1985.

Item 94 - Bridge Improvement Cost 6 digits

Code a 6-digit number to represent the estimated cost of the proposed 

bridge or major structure improvements in thousands of dollars. This 

cost shall include only bridge construction costs, excluding roadway, 

right of way, detour, demolition, preliminary engineering, etc. Code 

the base year for the cost in Item 97 - Year of Improvement Cost 

Estimate. Do not use this item for estimating maintenance costs.

This item must be coded for bridges eligible for the Highway Bridge 

Replacement and Rehabilitation Program. It may be coded for other 

bridges at the option of the highway agency.

EXAMPLES: Code

 Bridge Improvement Cost $ 55,850 000056

 250,000 000250

 7,451,233 007451

64
Item 94 - Bridge Improvement Cost (cont'd)

Nationally, the deck area of replaced bridges is averaging 2.2 times the 

deck area before replacement. The deck area of rehabilitated bridges is 

averaging 1.5 times the deck area before rehabilitation. Widening 

square meter costs are typically 1.8 times the square meter cost of new 

bridges with similar spans. For example, if the average cost of a new 

bridge is $500 per square meter, the average cost of the widened area 

would be $900 per square meter.

Each highway agency is encouraged to use its best available information 

and established procedures to determine bridge improvement costs. In 

the absence of these procedures, the highway agency may wish to use the 

following procedure as a guide in preparing bridge improvement cost 

estimates.

Apply a construction unit cost to the proposed bridge area developed by 

using (1) current State deck geometry design standards and (2) proposed 

bridge length from Item 76 - Length of Structure Improvement.

Item 95 - Roadway Improvement Cost 6 digits

Code a 6-digit number to represent the cost of the proposed roadway 

improvement in thousands of dollars. This shall include only roadway 

construction costs, excluding bridge, right-of-way, detour, extensive 

roadway realignment costs, preliminary engineering, etc. Code the base 

year for the cost in Item 97 - Year of Improvement Cost Estimate. Do 

not use this item for estimating maintenance costs.

This item must be coded for bridges eligible for the Highway Bridge 

Replacement and Rehabilitation Program. It may be coded for other 

bridges at the option of the highway agency.

In the absence of a procedure for estimating roadway improvement costs, 

a guide of 10 percent of the bridge costs is suggested.

Item 96 - Total Project Cost 6 digits

Code a 6-digit number to represent the total project cost in thousands 

of dollars, including incidental costs not included in Items 94 and 95. 

 This item should include all costs normally associated with the 

proposed bridge improvement project. The Total Project Cost will 

therefore usually be greater than the sum of Items 94 and 95. Code the 

base year for the cost in Item 97 - Year of Improvement Cost Estimate. 

Do not use this item for coding maintenance costs.

This item must be coded for bridges eligible for the Highway Bridge 

Replacement and Rehabilitation Program. It may be coded for other 

bridges at the option of the highway agency.

In the absence of a procedure for estimating the total project cost, a 

guide of 150 percent of the bridge cost is suggested.

65
Item 97 - Year of Improvement Cost Estimate 4 digits

Record and code the year that the costs of work estimated in Item 94 -

Bridge Improvement Cost, Item 95 - Roadway Improvement Cost, and Item 96 

- Total Project Cost were based upon. This date and the data provided 

for Item 94 through Item 96 must be current; that is, Item 97 shall be 

no more than 8 years old.

EXAMPLES: Code

 Year of Cost Estimate 1994 costs 1994

 2000 costs 2000

Item 98 - Border Bridge 5 digits

Use this item to indicate structures crossing borders of States. Code a 

5-digit number composed of 2 segments specifying the percent 

responsibility for improvements to the existing structure when it is on 

a border with a neighboring State. Code the first 3 digits with the 

neighboring State code using State codes listed in Item 1 - State Code. 

 Code the fourth and fifth digits with the percentage of total deck area 

of the existing bridge that the neighboring State is responsible for 

funding.

Segment Description Length

98A Neighboring State Code 3 digits

98B Percent Responsibility 2 digits

If a neighboring State codes the structure and accepts 100% of the 

responsibility, but your State still codes a record for the structure, 

then Item 98B in your State's record should be coded 99 to represent 

that your State has no responsibility for the structure.

For the special case of a structure on the border with Canada or Mexico, 

code the State code value = CAN or MEX respectively. If structure is 

not on a border, leave blank.

EXAMPLES: Code

 A structure connects your State with New Jersey 34245

 and New Jersey is responsible for funding

 45 percent of future improvement costs.

 A structure connects your State with MEX00

 Mexico and Mexico is not responsible for

 any funding of future improvement costs.

Item 99 - Border Bridge Structure Number 15 digits

Code the neighboring State's 15-digit National Bridge Inventory 

structure number for any structure noted in Item 98 - Border Bridge. 

This number must match exactly the neighboring State's submitted NBI 

structure number. The entire 15-digit field must be accounted for 

including zeros and blank spaces whether they are leading, trailing, or 

embedded in the 15-digit field. If Item 98 is blank, this item is 

blank.

In the above example where Mexico (or a neighboring State) has 00% 

responsibility, and, if there is no NBI Structure Number in that State's 

inventory file, then the entire 15-digit field shall be coded zeroes.

66
Item 100 - STRAHNET Highway Designation 1 digit

This item shall be coded for all records in the inventory. For the 

purposes of this item, the STRAHNET Connectors are considered included 

in the term STRAHNET. For the inventory route identified in Item 5, 

indicate STRAHNET highway conditions using one of the following codes:

 Code Description

 0 The inventory route is not a STRAHNET route.

 1 The inventory route is on a Interstate STRAHNET

route.

2 The inventory route is on a Non-Interstate

STRAHNET route.

3 The inventory route is on a STRAHNET connector 

 route.

Item 101 - Parallel Structure Designation 1 digit

Code this item to indicate situations where separate structures carry 

the inventory route in opposite directions of travel over the same 

feature. The lateral distance between structures has no bearing on the 

coding of this item. One of the following codes shall be used:

 Code Description

 R The right structure of parallel bridges 

carrying the roadway in the direction of the 

inventory. (For a STRAHNET highway, this is 

west to east and south to north.)

 L The left structure of parallel bridges. This 

structure carries traffic in the opposite 

direction.

 N No parallel structure exists.

EXAMPLE: Code

 Structure #1 R

 Structure #2 L 

67

2000
Item 102 - Direction of Traffic 1 digit

Code the direction of traffic of the inventory route identified in Item 

5 as a 1-digit number using one of the codes below. This item must be 

compatible with other traffic-related items such as Item 28A Lanes on 

the Structure, Item 29 - Average Daily Traffic, Item 47 - Total 

Horizontal Clearance and Item 51 - Bridge Roadway Width, Curb-to-Curb.

 Code Description

 0 Highway traffic not carried

 1 1-way traffic

 2 2-way traffic

 3 One lane bridge for 2-way traffic

Item 103 - Temporary Structure Designation 1 digit

Code this item to indicate situations where temporary structures or 

conditions exist. This item should be blank if not applicable.

 Code Description

 T Temporary structure(s) or conditions exist.

Temporary structure(s) or conditions are those which are required to 

facilitate traffic flow. This may occur either before or during the 

modification or replacement of a structure found to be deficient. Such 

conditions include the following:

! Bridges shored up, including additional temporary supports.

! Temporary repairs made to keep a bridge open.

! Temporary structures, temporary runarounds or bypasses.

! Other temporary measures, such as barricaded traffic lanes to keep 

the bridge open.

Any repaired structure or replacement structure which is expected to 

remain in place without further project activity, other than 

maintenance, for a significant period of time shall not be considered 

temporary. Under such conditions, that structure, regardless of its 

type, shall be considered the minimum adequate to remain in place and 

evaluated accordingly.

If this item is coded T, then all data recorded for the structure shall 

be for the condition of the structure without temporary measures, except 

for the following items which shall be for the temporary structure:

 Item 10 - Inventory Route, Minimum Vertical Clearance

41 - Structure Open, Posted, or Closed to Traffic

47 - Inventory Route, Total Horizontal Clearance

53 - Minimum Vertical Clearance Over Bridge Roadway

54 - Minimum Vertical Underclearance

55 - Minimum Lateral Underclearance on Right

56 - Minimum Lateral Underclearance on Left

70 - Bridge Posting

68
Item 104 - Highway System of the Inventory Route 1 digit

This item is to be coded for all records in the inventory. For the 

inventory route identified in Item 5, indicate whether the inventory 

route is on the National Highway System (NHS) or not on that system. 

Initially, this code shall reflect an inventory route on the NHS 

"Interim System" description in Section 1006(a) of the 1991 ISTEA. Upon 

approval of the NHS by Congress, the coding is to reflect the approved 

NHS. Use one of the following codes:

 Code Description

 0 Inventory Route is not on the NHS

 1 Inventory Route is on the NHS

Item 105 - Federal Lands Highways 1 digit

Structures owned by State and local jurisdictions on roads which lead to 

and traverse through federal lands sometimes require special coded 

unique identification because they are eligible to receive funding from 

the Federal Lands Highway Program. One of the following codes shall be 

used:

 Code Description

 0 Not applicable

 1 Indian Reservation Road (IRR)

 2 Forest Highway (FH)

 3 Land Management Highway System (LMHS)

 4 Both IRR and FH

 5 Both IRR and LMHS

 6 Both FH and LMHS

 9 Combined IRR, FH and LMHS

 

Item 106 - Year Reconstructed 4 digits

Record and code the year of most recent reconstruction of the structure. 

 Code all 4 digits of the latest year in which reconstruction of the 

structure was completed. If there has been no reconstruction code 0000.

For a bridge to be defined as reconstructed, the type of work performed, 

whether or not it meets current minimum standards, must have been 

eligible for funding under any of the Federal-aid funding categories. 

The eligibility criteria would apply to the work performed regardless of 

whether all State or local funds or Federal-aid funds were used.

Some types of eligible work not to be considered as reconstruction are 

listed:

- Safety feature replacement or upgrading (for example, bridge 

rail, approach guardrail or impact attenuators).

- Painting of structural steel.

69
Item 106 - Year Reconstructed (cont'd)

- Overlay of bridge deck as part of a larger highway surfacing 

project (for example, overlay carried across bridge deck for 

surface uniformity without additional bridge work).

- Utility work.

- Emergency repair to restore structural integrity to the previous 

status following an accident.

- Retrofitting to correct a deficiency which does not 

substantially alter physical geometry or increase the loadcarrying capacity.

- Work performed to keep a bridge operational while plans for 

complete rehabilitation or replacement are under preparation 

(for example, adding a substructure element or extra girder).

EXAMPLE: Code

 Reconstruction completed 1970 1970

Item 107 - Deck Structure Type 1 digit

Record the type of deck system on the bridge. If more than one type of 

deck system is on the bridge, code the most predominant. Code N for a 

filled culvert or arch with the approach roadway section carried across 

the structure. Use one of the following codes:

 Code Description

 1 Concrete Cast-in-Place

 2 Concrete Precast Panels

 3 Open Grating

 4 Closed Grating

 5 Steel plate (includes orthotropic)

 6 Corrugated Steel

 7 Aluminum

 8 Wood or Timber

 9 Other

 N Not applicable

Item 108 - Wearing Surface/Protective System 3 digits

Information on the wearing surface and protective system of the bridge 

deck shall be coded using a 3-digit code composed of 3 segments.

 Segment Description Length

 108A Type of Wearing Surface 1 digit

 108B Type of Membrane 1 digit

 108C Deck Protection 1 digit

70
Item 108 - Wearing Surface/Protective System (cont'd)

1st Digit - Type of Wearing Surface (Item 108A):

 Code Description

 1 Monolithic Concrete (concurrently placed

 with structural deck)

 2 Integral Concrete (separate non-modified layer 

of concrete added to structural deck)

 3 Latex Concrete or similar additive

 4 Low Slump Concrete

 5 Epoxy Overlay

 6 Bituminous

 7 Wood or Timber

 8 Gravel

 9 Other

 0 None (no additional concrete thickness or 

wearing surface is included in the bridge 

deck)

 N Not Applicable (applies only to structures 

with no deck)

 

2nd Digit - Type of Membrane (Item 108B):

 Code Description

 1 Built-up

 2 Preformed Fabric

 3 Epoxy

 8 Unknown

 9 Other

 0 None

 N Not Applicable (applies only to structures

 with no deck)

3rd Digit - Deck Protection (Item 108C):

 Code Description

 1 Epoxy Coated Reinforcing

 2 Galvanized Reinforcing

 3 Other Coated Reinforcing

 4 Cathodic Protection

 6 Polymer Impregnated

 7 Internally Sealed

 8 Unknown

 9 Other

 0 None

 N Not Applicable (applies only to structures

 with no deck)

71
Item 109 - Average Daily Truck Traffic (XX percent) 2 digits

Code a 2-digit percentage that shows the percentage of Item 29 - Average 

Daily Traffic that is truck traffic. Do not include vans, pickup trucks 

and other light delivery trucks in this percentage.

If this information is not available, an estimate which represents the 

average percentage for the category of road carried by the bridge may be 

used. May be left blank if Item 29 - Average Daily Traffic is not 

greater than 100.

EXAMPLES: Code

 Average Daily Traffic 7% trucks 07

 12% trucks 12

Item 110 - Designated National Network 1 digit

The national network for trucks includes most of the Interstate System 

and those portions of Federal-Aid highways identified in the Code of 

Federal Regulations (23 CFR 658). The national network for trucks is 

available for use by commercial motor vehicles of the dimensions and 

configurations described in these regulations. For the inventory route 

identified in Item 5, indicate conditions using one of the following 

codes:

 Code Description

 0The inventory route is not part of the national network for 

trucks.

 1The inventory route is part of the national network for 

trucks.

Item 111 - Pier or Abutment Protection (for Navigation) 1 digit

If Item 38 - Navigation Control has been coded 1, use the codes below to 

indicate the presence and adequacy of pier or abutment protection 

features such as fenders, dolphins, etc. The condition of the 

protection devices may be a factor in the overall evaluation of Item 60 

- Substructure. If Item 38 - Navigation Control has been coded 0 or N, 

leave blank to indicate not applicable.

 Code Description

1 Navigation protection not required

2 In place and functioning

3 In place but in a deteriorated condition

4 In place but reevaluation of design

 suggested

5 None present but reevaluation suggested

72
Item 112 - NBIS Bridge Length 1 digit

Does this structure meet or exceed the minimum length specified to be 

designated as a bridge for National Bridge Inspection Standards 

purposes? The following definition of a bridge is to be used:

A structure including 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* between undercopings of abutments or spring lines of 

arches, or extreme ends of openings for multiple boxes; it may also 

include multiple pipes, where the clear distance between openings is 

less than half of the smaller contiguous opening.

* (6.1 meters).

 Code Description

 Y Yes

 N No

EXAMPLES:

(1) Item 112 - NBIS Bridge Length 

73
Item 112 – NBIS Bridge Length (cont’d)

EXAMPLES:

 (1) Item 112 - NBIS Bridge Length

74
Item 113 - Scour Critical Bridges 1 digit

Use a single-digit code as indicated below to identify the current 

status of the bridge regarding its vulnerability to scour. Scour 

analyses shall be made by hydraulic/geotechnical/structural engineers. 

Details on conducting a scour analysis are included in the FHWA 

Technical Advisory 5140.23 titled, "Evaluating Scour at Bridges." 

Whenever a rating factor of 4 or below is determined for this item, the 

rating factor for Item 60 - Substructure may need to be revised to 

reflect the severity of actual scour and resultant damage to the bridge. 

 A scour critical bridge is one with abutment or pier foundations which 

are rated as unstable due to (1) observed scour at the bridge site or 

(2) a scour potential as determined from a scour evaluation study.

CodeDescription

N Bridge not over waterway.

U Bridge with "unknown" foundation that has not been evaluated for 

scour. Since risk cannot be determined, flag for monitoring during 

flood events and, if appropriate, closure. 

T Bridge over "tidal" waters that has not been evaluated for scour, 

but considered low risk. Bridge will be monitored with regular 

inspection cycle and with appropriate underwater inspections. 

("Unknown" foundations in "tidal" waters should be coded U.)

9 Bridge foundations (including piles) on dry land well above flood 

water elevations.

8 Bridge foundations determined to be stable for assessed or 

calculated scour conditions; calculated scour is above top of 

footing. (Example A)

7 Countermeasures have been installed to correct a previously existing 

problem with scour. Bridge is no longer scour critical.

6 Scour calculation/evaluation has not been made. (Use only to 

describe case where bridge has not yet been evaluated for scour 

potential.)

5 Bridge foundations determined to be stable for calculated scour 

conditions; scour within limits of footing or piles. (Example B)

4 Bridge foundations determined to be stable for calculated scour 

conditions; field review indicates action is required to protect 

exposed foundations from effects of additional erosion and 

corrosion.

3 Bridge is scour critical; bridge foundations determined to be 

unstable for calculated scour conditions:

- Scour within limits of footing or piles. (Example B)

- Scour below spread-footing base or pile tips. (Example C)

 (codes continued on the next page)

75
Item 113 - Scour Critical Bridges (cont'd)

CodeDescription

2 Bridge is scour critical; field review indicates that extensive 

scour has occurred at bridge foundations. Immediate action is 

required to provide scour countermeasures.

1 Bridge is scour critical; field review indicates that failure of 

piers/abutments is imminent. Bridge is closed to traffic.

0 Bridge is scour critical. Bridge has failed and is closed to 

traffic.

EXAMPLES: CALCULATED SCOUR DEPTH ACTION NEEDED

76
Item 114 - Future Average Daily Traffic 6 digits

Code for all bridges the forecasted average daily traffic (ADT) for the 

inventory route identified in Item 5. This shall be projected at least 

17 years but no more than 22 years from the year of inspection. The 

intent is to provide a basis for a 20-year forecast. This item may be 

updated anytime, but must be updated when the forecast falls below the 

17-year limit. If planning data is not available, use the best estimate 

based on site familiarity.

The future ADT must be compatible with the other items coded for the 

bridge. For example, parallel bridges with an open median are coded as 

follows: if Item 28 -Lanes On and Under the Structure and Item 51 -

Bridge Roadway Width, Curb-to-Curb are coded for each bridge separately, 

then the future ADT must be coded for each bridge separately (not the 

total for the route).

EXAMPLES: Code

 Future ADT 540 000540

 15,600 015600

 240,000 240000

Item 115 - Year of Future Average Daily Traffic 4 digits

Record and code the year represented by the future ADT in Item 114. The 

projected year of future ADT shall be at least 17 years but no more than 

22 years from the year of inspection.

EXAMPLE: Code

 Year of Future ADT is 2014 2014

Item 116 - Minimum Navigation Vertical Clearance,

 Vertical Lift Bridge (XXX.X meters) 4 digits

Record and code as a 4-digit number truncated to the tenth of a meter 

(with an assumed decimal point), the minimum vertical clearance imposed 

at the site as measured above a datum that is specified on a navigation 

permit issued by a control agency. Code this item only for vertical 

lift bridges in the dropped or closed position, otherwise leave blank.

EXAMPLES: Code

 Vertical Clearance 10.67 meters 0106

 24.22 meters 0242

77
GENERAL

Inspection reports should generally include the following:

1. A statement of action taken, if any, pursuant to findings of 

inspection.

2. Any special findings stemming from the inspection and evaluation of 

 fracture critical members, underwater inspections, and special 

feature inspection.

3. Any features which should be monitored closely during subsequent 

inspections as should any specific descriptions, instructions, or 

concerns.

Measurements, sketches, diagrams, test results, or calculations should 

generally be included on separate sheets.

78
APPENDIX A

Structure Inventory and Appraisal Sheet
A-1
APPENDIX B

Sufficiency Rating Formula and Example
Appendix B

Sufficiency Rating Formula and Example

The sufficiency rating formula described herein is a method of 

evaluating highway bridge data by calculating four separate factors to 

obtain a numeric value which is indicative of bridge sufficiency to 

remain in service. The result of this method is a percentage in which 

100 percent would represent an entirely sufficient bridge and zero 

percent would represent an entirely insufficient or deficient bridge.

An asterisk prefix is used to identify a sufficiency rating that was 

calculated even though some essential data was missing or coded 

incorrectly. The Edit/Update Program will substitute a value for the 

unusable data (which will not lower the rating) and calculate the 

sufficiency rating. The asterisk is dropped when the unusable data is 

corrected. It is normal that all culverts with Bridge Roadway Width, 

Curb-to-Curb - Item 51 coded '0000' will have an asterisk prefixed 

sufficiency.

B-1
Figure 1. Summary of Sufficiency Rating Factors

B-2
Sufficiency Rating Formula

1. Structural Adequacy and Safety (55% maximum)

 a. Only the lowest rating code of Item 59, 60, or 62 applies.

 If Item 59 (Superstructure Rating) or

 Item 60 (Substructure Rating) is < 2 then A = 55%

 = 3 A = 40%

 = 4 A = 25%

 = 5 A = 10%

 If Item 59 and Item 60 = N and

 Item 62 (Culvert Rating) is < 2 then A = 55%

 = 3 A = 40%

 = 4 A = 25%

 = 5 A = 10%

 b. Reduction for Load Capacity:

 Calculate using the following formulas where

 IR is the Inventory Rating (MS Loading) in tons

 or use Figure 2:

 

 B = (32.4 - IR)1.5 x 0.3254

 or

 If (32.4 - IR) < 0, then B = 0

 "B" shall not be less than 0% nor greater than 55%.

 S1 = 55 - (A + B)

 S1 shall not be less than 0% nor greater than 55%.

B-3
FIGURE 2. Reduction for Load Capacity

B-4
2. Serviceability and Functional Obsolescence (30% maximum)

 a. Rating Reductions (13% maximum)

 If #58 (Deck Condition) is < 3 then A = 5%

 = 4 A = 3%

 = 5 A = 1%

 If #67 (Structural Evaluation) is < 3 then B = 4%

 = 4 B = 2%

 = 5 B = 1%

 If #68 (Deck Geometry) is < 3 then C = 4%

 = 4 C = 2%

 = 5 C = 1%

 If #69 (Underclearances) is < 3 then D = 4%

 = 4 D = 2%

 = 5 D = 1%

 If #71 (Waterway Adequacy) is < 3 then E = 4%

 = 4 E = 2%

 = 5 E = 1%

 If #72 (Approach Road Alignment) is < 3 then F = 4%

 = 4 F = 2%

 = 5 F = 1%

 J = (A + B + C + D + E + F)

 J shall not be less than 0% nor greater than 13%.

 b. Width of Roadway Insufficiency (15% maximum)

 Use the sections that apply:

 (1) applies to all bridges;

 (2) applies to 1-lane bridges only;

 (3) applies to 2 or more lane bridges;

 (4) applies to all except 1-lane bridges.

 Also determine X and Y:

 X (ADT/Lane) = Item 29 (ADT) 

 first 2 digits of #28 (Lanes)

 Y (Width/Lane)* = Item 51 (Bridge Rdwy. Width)

 first 2 digits of #28 (Lanes)

*A value of 10.9 Meters will be substituted when item 51 is coded 0000 

or not numeric.

B-5

2000
 (1) Use when the last 2 digits of #43 (Structure Type) are 

 not equal to 19 (Culvert):

 If(#51 + 0.6 meters) < #32 (Approach Roadway Width) G = 5%

 (2) For 1-lane bridges only, use Figure 3 or the following:

 If the first 2 digits of #28 (Lanes) are equal to 01 and

 Y < 4.3 then H = 15%

 

 Y > 4.3 < 5.5 H =

 

Y > 5.5 H = 0% 

 (3) For 2 or more lane bridges. If these limits apply,

 do not continue on to (4) as no lane width reductions

 are allowed.

 If the first 2 digits of #28 = 02 and Y > 4.9, H = 0%

 If the first 2 digits of #28 = 03 and Y > 4.6, H = 0%

 If the first 2 digits of #28 = 04 and Y > 4.3, H = 0%

 If the first 2 digits of #28 > 05 and Y > 3.7 H = 0%

 (4) For all except 1-lane bridges,use Figure 3 or the following:

 If Y < 2.7 and X > 50 then H = 15%

 Y < 2.7 and X < 50 H = 7.5%

 Y > 2.7 and X < 50 H = 0%

 If X > 50 but < 125 and

 Y < 3.0 then H = 15%

 Y > 3.0 < 4.0 H = 15(4-Y)%

 Y > 4.0 H = 0%

 If X > 125 but < 375 and

 Y < 3.4 then H = 15%

 Y > 3.4 < 4.3 H = 15(4.3-Y)%

 Y > 4.3 H = 0%

B-6

%

1.2

5.5

15 









 − Y
Figure 3. Width of Roadway Insufficiency

 B-7
 If X > 375 but < 1350 and

 Y < 3.7 then H = 15%

 Y > 3.7 < 4.9 H = 

 Y > 4.9 H = 0%

 If X > 1350 and

 Y < 4.6 then H = 15%

 Y > 4.6 < 4.9 H = 

 Y > 4.9 H = 0%

 

 G + H shall not be less than 0% nor greater than 15%.

 c. Vertical Clearance Insufficiency - (2% maximum)

 If #100 (STRAHNET Highway Designation) > 0 and

 #53 (VC over Deck) > 4.87 then I = 0%

 #53 < 4.87 I = 2%

 If #100 = O and

 #53 > 4.26 then I = 0%

 #53 < 4.26 I = 2%

 S2 = 30 - [ J + (G + H) + I ]

 S2 shall not be less than 0% nor greater than 30%.

3. Essentiality for Public Use (15% maximum)

 a. Determine:

 S1 + S2

 K = _________

 85

B-8

%

1.2

4.9

15 









 − Y

%

1.2

4.9

15 









 − Y
 

b. Calculate: 

A = 

 

 "A" shall not be less than 0% nor greater than 15%.

 c. STRAHNET Highway Designation:

 If #100 is > 0 then B = 2%

 If #100 = 0 then B = 0%

 S3 = 15 - (A + B)

 S3 shall not be less than 0% nor greater than 15%.

4. Special Reductions (Use only when S1 + S2 + S3 > 50)

 a. Detour Length Reduction, use Figure 4 or the following:

 A = (#19)4 x (7.9 x 10-9)

 "A" shall not be less than 0% nor greater than 5%.

 b. If the 2nd and 3rd digits of #43 (Structure Type, Main)

 are equal to 10, 12, 13, 14, 15, 16, or 17; then

 B = 5%

 c. If 2 digits of #36 (Traffic Safety Features) = 0 C = 1%

 If 3 digits of #36 = 0 C = 2%

 If 4 digits of #36 = 0 C = 3%

 S4 = A + B + C

 S4 shall not be less than 0% nor greater than 13%.

_________________________________________________________________

 Sufficiency Rating = S1 + S2 + S3 - S4

 The Rating shall not be less than 0% nor greater than 100%.

B-9













xK

ADT x DetourLength

320,000

#29( ) #19(

15
Figure 4. Special Reduction for Detour Length

B-10
25.2( ,max . 15)

320,000 0.44

18,500 12.8

15 = = 











however allowable

x

x Km

EXAMPLE

Calculation of Sufficiency Rating

1. Structural Adequacy and Safety

 A = 10%

 B = [32.4 - (19.8 metric tons)]1.5 x 0.3254 = 14.6

 S1 = 55 - (10 + 14.6) = 30.4

2. Serviceability and Functional Obsolescence

 

 A = 3%, B = 1%, C = 4%, D = NA, E = NA, F = NA

 J = (3 + 1 + 4) = 8%

 X = 18500 = 9250 Y = 7.9 m = 3.95

 2 2

 (1) If (7.9 + 0.6) < 12.2 then G = 5

 (2) Not Applicable

 (3) Not Applicable

 (4) If X = 9250 and Y = 3.95 then H = 15

 G + H = 5 + 15 = 20 (however, maximum allowable = 15)

 I = 0

 S2 = 30 - [ 8 + (15) + 0 ] = 7.0

3. Essentiality For Public Use

 K = 30.4 + 7.0 = 0.44

 85

 A = 

 B = 0

 S3 = 15 - (15 + 0) = 0

B-11
4. Special Reductions

 S1 + S2 + S3 = (30.4 + 7.0 + 0.0) = 37.4 < 50

 

 S4 = NA

____________________________________________________________

 SUFFICIENCY RATING = 30.4 + 7.0 + 0.0 = 37.4

____________________________________________________________

B-12
B-13
APPENDIX C

National Bridge Inspection Standards

Section 650.311 - The January 1979 Coding Guide has been superseded by a 

December 1988 Guide, which is superseded by this metric version of the 

Coding Guide.

 
Appendix C

National Bridge Inspection Standards

CODE OF FEDERAL REGULATIONS

23 HIGHWAYS - PART 650

Subpart C - National Bridge 

 Inspection Standards

'650.301 Application of

standards.

The National Bridge

Inspection Standards in this 

part apply to all structures 

defined as bridges located

on all public roads. In

accordance with the AASHT0

(American Association of

State Highway and

Transportation Officials)

Transportation Glossary, a

"bridge" is defined as a

structure including 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 between undercopings of 

abutments or spring lines of 

arches, or extreme ends of

openings for multiple boxes; 

it may also include multiple 

pipes, where the clear

distance between openings is 

less than half of the

smaller contiguous opening.

'650.303 Inspection

procedures.

 (a) Each highway 

department shall include a

bridge inspection

organization capable of

performing inspections,

preparing reports, and

determining ratings in

accordance with the

provisions of the AASHTO

Manual1 and the Standards

contained herein.

 (b) Bridge inspectors 

shall meet the minimum

qualifications stated in

'650.307.

 

 (c) Each structure

required to be inspected

under the Standards shall be 

rated as to its safe load

carrying capacity in

accordance with 

Section 4 of the AASHTO

Manual. If it is determined 

under this rating procedure 

that the maximum legal load 

under State law exceeds the 

load permitted under the

Operating Rating, the bridge 

must be posted in conformity 

with the AASHTO 

Manual or in accordance with 

State law.

 (d) Inspection records

and bridge inventories shall 

be prepared and maintained

in accordance with the

Standards.

 (e) The individual in

charge of the organizational 

unit that has been delegated 

the responsibilities for

bridge inspection, reporting

and inventory shall

determine and designate on

the individual inspection

and inventory records and

maintain a master list of

the following:

 (1) Those bridges which

contain fracture critical

members, the location and

description of such members 

on the bridge and the 

inspection frequency and

procedures for inspection of 

such members. (Fracture 

critical members are tension 

members of a bridge whose

failure will probably cause 

a portion of or the entire

bridge to collapse.)

 (2) Those bridges with

underwater members which

cannot be visually evaluated 

during periods of low flow

or examined by feel for

condition, integrity and

safe load capacity due to

excessive water depth or

turbidity. These members

shall be described, the

inspection frequency stated

not to exceed five years,

and the inspection procedure 

specified.

 C-1

 (3) Those bridges which

contain unique or special

features requiring

additional attention during

inspection to ensure the

safety of such bridges and

the inspection frequency and 

procedure for inspection of 

each such feature.

 (4) The date of last

inspection of the features

designated in paragraphs

(e)(1) through (e)(3) of

this section and a

description of the findings 

and follow-up actions, if

necessary, resulting from

the most recent inspection

of fracture critical

details, underwater members

or special features of each 

so designated bridge.

'650.305 Frequency of

inspections.

 (a) Each bridge is to be 

inspected at regular

intervals not to exceed 2

years in accordance with

Sect. 2.3 of the AASHTO

Manual.

1 The "AASHTO Manual"

referred to in this part is 

the 'Manual for Maintenance 

Inspection of Bridges 1983" 

together with subsequent

interim changes or the most 

recent version of the AASHTO 

manual published by the

American Association of

State Highway and

Transportation Officials. A

copy of the Manual may be

examined during normal

business hours at the office 

of each Division

Administrator of the Federal 

Highway Administration, at

the office of each Regional 

Federal Highway

Administrator, and at the

Washington Headquarters of

the Federal Highway

Administration. The

addresses of those document 

inspection facilities are

set forth in Appendix D to

Part 7 of the regulations of 

the Office of the Secretary 

(40 CFR Part 7). In

addition, a copy of the

Manual may be secured upon

payment in advance by

writing to the American

Association of State 
Highway and Transportation

Officials, 444 N. Capitol

Street, N.W., Suite 225, 

Washington, D.C. 20001.

 (b) Certain types or

groups of bridges will

require inspection at less

than 2-year intervals. The

depth and frequency to which 

bridges are to be inspected 

will depend on such factors 

as age, traffic

characteristics, state of

maintenance, and known

deficiencies. The evaluation

of these factors will be the 

responsibility of the

individual in charge of the 

inspection program.

 (c) The maximum

inspection interval may be

increased for certain types 

or groups of bridges where

past inspection reports and 

favorable experience and

analysis justifies the

increased interval of

inspection. If a State

proposes to inspect some

bridges at greater than the 

specified 2-year interval,

the State shall submit a

detailed proposal and

supporting data to the

Federal Highway

Administrator for approval.

'650.307 Qualifications of

personnel.

 (a) The individual in

charge of the organizational 

unit that has been delegated 

the responsibilities for

bridge inspection,

reporting, and inventory

shall possess the following 

minimum qualifications:

 (1) Be a registered 

professional engineer; or

 (2) Be qualified for

registration as a

professional engineer under

the laws of the State; or

 (3) Have a minimum of 10 

years experience in bridge

inspection assignments in a 

responsible capacity and

have completed a

comprehensive training

course based on the, "Bridge 

Inspector's Training

Manual"2, which has been

developed by a joint

Federal-State task force,

and subsequent additions to 

the manual.3

 (b) An individual in charge 

of a bridge inspection team 

shall possess the following 

minimum qualifications:

 (1) Have the

qualifications specified in

paragraph (a) of this

section; or

 (2) Have a minimum of 5

years experience in bridge

inspection assignments in a 

responsible capacity and

have completed a

comprehensive training 

course based on the "Bridge 

Inspector's Training

Manual", which has been

developed by a joint

Federal-State task force.

 (3) Current certification

as a Level III or IV Bridge 

Safety Inspector under the

National Society of

Professional Engineer's

program for National

Certification in Engineering

Technologies (NICET)4 is an

alternative acceptable means

for establishing that a

bridge inspection team

leader is qualified.

'650.309 Inspection report.

The findings and results of 

bridge inspections shall be 

recorded on standard forms. 

The data required to

complete the forms and the

functions which must be

performed to compile the

data are contained in

Section 3 of the AASHT0

Manual

2The "Bridge Inspector's

Training Manual" may be

purchased from the

Superintendent of Documents,

U.S. Government Printing

Office, Washington, D.C.

20402.

3The following publications

are supplements to the

"Bridge Inspector's Training

Manual": "Bridge Inspector's

Manual for Movable Bridges," 

1977, GPO Stock No.

050-00200103-5; "Culvert 

Inspector's Training

Manual," July 1986, GPO

Stock No. 050-001-0030-7; 

and "Inspection of Fracture 

Critical Bridge Members,"

1986, GPO Stock No.

050-00100302-3.

 C-2

'650.311 Inventory.

 (a) Each State shall

prepare and maintain an

inventory of all bridge

structures subject to the

Standards. Under these

Standards, certain structure

inventory and appraisal data 

must be collected and

retained within the various 

departments of the State

organization for collection

by the Federal Highway

Administration as needed. A 

tabulation of this data is

contained in the structure

inventory and appraisal

sheet distributed by the

Federal Highway

Administration as part of

the Recording and Coding

Guide for the Structure

Inventory and Appraisal of 

the Nation's Bridges (Coding 

Guide) in January of 1979.

Reporting procedures have

been developed by the

Federal Highway

Administration.

 (b) Newly completed

structures, modification of

existing structures which

would alter previously

recorded data on the

inventory forms or placement 

of load restriction signs on 

the approaches to or at the 

structure itself shall be

entered in the State's

inspection reports and the

computer inventory file as

promptly as practical, but

no later than 90 days after 

the change in the status of 

the structure for bridges

directly under the State's

jurisdiction and no later

than 180 days after the

change in status of the

structure for all other

bridges on public roads

within the State.

4For information on NICET

program certification 

contact: National Institute

for Certification in

Engineering Technologies 

1420 King Street,

Alexandria, Virginia 22314. 

 Attention: 

John D. Antrim, P.E., Phone 

(703) 684-2835.

 

Effective date October 25.

1988.
APPENDIX D

Commentary

The 22 page commentary contained in the 1988 Coding Guide has not been 

included in this document. The following pages of commentary, however, 

show item by item changes caused by this revision. 
Appendix D

December 1994 Commentary

This commentary provides a ready reference for item by item changes 

between the 1988 Coding Guide and this proposed revision. Items not 

specifically mentioned here are essentially unchanged except for SI 

metric conversion.

Introduction

! Mentions new items and their use.

! References to Defense Bridges removed and STRAHNET added.

! Federal agencies specifically included in this Guide.

! Minor editorial changes and reference revisions have been made to 

bring the text up to date.

Definition of Terms

! The order of the definitions has changed and the following added or 

modified:

(a) Bridge length has been converted to metric.

 The length of 20 feet has been changed to 6.1 meters. 

(b) Culvert.

(i) Strategic Highway Corridor Network (STRAHNET). Replaces Defense

Items, which were dropped.

(j) STRAHNET Connectors. 

(k) Indian Reservation Road definition has been added.

(l) Land Management Highway System (LMHS)

(m) Forest Highway (FH)

(n) Forest Service Development Road.

(o) Base Highway Network.

(p) Highway Performance Monitoring System.

(q) Conversion of Numerical Data

(r) Rounding and Truncating of Numerical Data.

Item 2 - Highway Agency District

! Name of item changed to reflect inclusion of federal bridges.

Item 5A - Record Type

! Clarification has been made for the case of 2 or more routes passing 

under a structure.

! Items 30, and 109 have been added to the list of items required to be 

coded for "under" records.

D-1
Item 6 - Features Intersected

! Item coding requirements have been clarified for "under" records.

! References to defense highway and FHPM 6-10-2 have been eliminated.

! Critical facilities are now STRAHNET and STRAHNET Connectors.

Item 7 - Facility Carried by Structure

! Item coding requirements have been clarified for "under" records.

! Temporary use of this item for coding IRR has been changed to Item 

105.

Item 8 - Structure Number

! Closed median has been described.

! Additional emphasis has been given to the need to have all 15 digits 

filled.

Item 10 - Inventory Route, Minimum Vertical Clearance

! Units of measurement have been converted to metric, using a 3-meter 

width of pavement.

! Vertical restrictions 30 meters or greater may now be coded 9999, 

with exact actual clearances in this range optional.

Item 11 - Kilometer Point

! Units of measurement and the description of the item have been 

converted to metric.

! Seven digits will be coded instead of six.

Item 12 - Base Highway Network

! New item added for use in identifying Linear Referencing System 

(LRS).

Item 13 - LRS Inventory Route, Subroute Number

! New item added for identifying LRS. 

Item 16 - Latitude and Item 17 - Longitude

! Number of digits have been expanded to 8 and 9 digits, respectively.

! The format of the item allows an increased precision of measurement 

(not mandatory) to accommodate the use of the Global Positioning 

System (GPS). Current measuring methods and level of precision may 

continue to be used.

References to defense highways changed to STRAHNET.

D-2
! Location where measurement is taken must be compatible with the LRS.

Item 19 - Bypass, Detour Length

! Number of digits has been expanded to three to accommodate metric. 

Item 20 - Toll

! Reference to Secretarial Agreement updated.

Item 21 - Maintenance Responsibility and Item 22 - Owner

! Several federal agencies have been added.

Item 26 - Functional Classification of Inventory Route

! This item is no longer compatible with Item 104 and appropriate 

revisions have been made.

Item 28 - Lanes On and Under the Structure

! Text clarified for "under" records.

! Text has been added advising that any "1-lane" bridge 4.9 meters or 

greater in curb-to curb width is evaluated as 2 lanes or more in Item 

68 -Deck Geometry.

Item 29 - Average Daily Traffic

! Text has been added explaining that if the bridge is closed, the 

coding is to be the actual ADT from the period before the closure 

occurred.

Item 30 - Year of Average Daily Traffic

! Field expanded to four digits to allow coding of complete year. 

Item 31 - Design Load

! Codes have been converted from the H and HS loadings to metric M and 

MS loadings. 

Item 32 - Approach Roadway Width

! A hard conversion of the units of measure has been used to match the 

metric standards of AASHTO.

Item 36 - Traffic Safety Features

! Add and update reference publications.

! Segment A has been updated to include the latest FHWA policy on crash 

testing and other recommended barrier specifications.

! Note on national set of standards updated.

D-3
Item 38 - Navigation Control

Term bridge permit clarified.

Item 41 - Structure Open, Posted or Closed to Traffic

Code B has been clarified concerning signs not correctly implemented. 

An example of "not correctly implemented" is existing posting signs not 

changed to indicate a lower load posting calculated for more recent 

inspection conditions.

Code P expanded to include temporary bridges which are load posted.

Item 43 - Structure Type, Main

Segment A codes 5 and 6 have been noted to include post-tensioned 

concrete.

Segment B code 07 has been noted that frame culverts are excluded. 

Code 19 has been noted that frame culverts are included. 

Item 47 - Inventory Route, Total Horizontal Clearance

FHPM reference has been eliminated.

In addition to the metric changes and editorial clarifications, the 

definition for clearance has been modified. 

Item 48 - Length of Maximum Span

The units of measurement have been converted to metric and the number of 

digits expanded to 5 digits to accommodate the metric values.

Center to center measurements specified to be center of bearing points.

Item 49 - Structure Length

In addition to the metric changes, an explanation has been added 

concerning the measuring and coding of tunnels.

Item 50 - Curb or Sidewalk Widths

Example figure modified to accentuate the mountable median.

Item 51 - Bridge Roadway Width, Curb-to-Curb

In addition to the metric changes, a reference has been added for the 

case of sidehill viaducts. A sidehill viaduct has a portion of its 

width on embankment and a portion on structure. The problem arises in 

calculating Item 68, the sufficiency rating and the deck area of the 

bridge. Commentary Figure 1 illustrates the coding of sidehill 

viaducts.

D-4
Commentary Figure 1

FIGURE ILLUSTRATING CODING

OF SIDEHILL VIADUCTS

Associated Items:

Item 28A - Lanes On Structure 

Item 29 - ADT = Total for entire structure

Item 32 - Approach Roadway Width 

Item 102 - Direction of Traffic = 2 for 2-way

D-5
Item 53 - Minimum Vertical Clearance Over Bridge Roadway

! Units of measurement have been converted to metric.

! Clarification has been added for recording the minimum vertical 

clearance for double decked structures.

! Restrictions of 30 meters or greater or no superstructure restriction 

are now both to be coded 9999. However coding of actual clearances 

between 30 and 99.99 meters to an exact measurement is optional.

Item 54 - Minimum Vertical Underclearance

! In addition to metric changes, instructions have been given to code 

restrictions of 30 meters or greater as code 9999. However coding of 

actual clearances between 30 and 99.99 meters to an exact measurement 

is optional.

Item 55 - Minimum Lateral Underclearance on Right

! In addition to metric changes, instructions have been given for the 

coding of restrictions 30 meters or greater. The numeric value in 

segment B is to be coded 999 for restrictions of 30 meters or 

greater. However coding of actual clearances between 30 and 99.9 

meters to an exact measurement is optional.

! If the feature beneath the structure is not a railroad or highway, 

the code 000 in the numeric value for segment B is to indicate that 

the item is not applicable. This replaces the previous code of 999 

to indicate that the item is not applicable.

Item 56 - Minimum Lateral Underclearance on Left.

! Care should be used in coding bridges with "open" medians, they 

should be coded 999. Those with clearances greater than 30 meters 

may be coded 998. However coding of actual clearances between 30 and 

99.8 meters to an exact measurement is optional. When indicating 

that the item is not applicable code 000.

Item 58 - Deck

! Clarification has been added for "structures without decks".

Item 61 - Channel and Channel Protection

! The word channel is now consistently used in this item.

Item 63 - Method Used to Determine Operating Rating.

! New item added for use with Operating Rating.

D-6
Item 64 - Operating Rating

! The entire item has been redefined using the MS rating system instead 

of the previous HS vehicle ratings. Instructions have been given to 

code a 3 digit number representing the total weight in metric tons of 

the entire vehicle (maximum load).

! A description has been added indicating that the load factor (LF) 

method is to be used for determining operating ratings and inventory 

ratings.

! A change has been made to advise that with the coding for metric 

tonnage, the codes 200 or 900 are not appropriate for temporary 

bridges. Code 000 is to be used.

! Instructions have been given to use code 999 for a structure under a 

fill where live load is insignificant in the structure load capacity.

Item 65 - Method Used to Determine Inventory Rating

! New item added for use with Inventory Rating.

Item 66 - Inventory Rating

! See commentary for Item 64 - Operating Rating.

Items 67, 68, 69, 71, and 72 - Indicate the Appraisal Ratings

! Information has been provided advising that the Edit/Update computer 

calculates the codes for Items 67, 68 and 69, based on the Coding 

Guide tables for these items. Values entered by bridge owners or 

inspectors are not used.

! Because the level of service concept is no longer being considered, 

all reference to level of service has been eliminated.

Item 67 - Structural Evaluation

! This item is calculated by the Edit/Update program and need not be 

coded in the field. The reference to how the item was to be coded by 

bridge inspectors has been eliminated. Editorial changes have also 

been made to indicate the specifications on which the Edit/Update 

program is based.

! The load rating vehicle conversion factors have been eliminated as 

only MS (previously HS) ratings are to be coded into the inventory 

rating item.

! Table 1 has been converted to metric values for the MS inventory 

ratings. Note that the inventory ratings have been shown in total 

metric tons with the decimal point included instead of assumed. The 

MS equivalent values have been included in the table.

D-7
Item 68 - Deck Geometry

! This item is calculated by the Edit/Update program and need not be 

coded in the field. Editorial changes have also been made to 

indicate the specifications on which the Edit/Update program is 

based.

! A statement has been added to advise that culverts coded 0000 for 

roadway width will be given the coding of N for this item.

! All tables have been converted to metric units of measurement. Where 

appropriate, a hard conversion has been used to match the metric 

standards of AASHTO.

! A note has been added to advise that one-lane bridges 4.90 meters and 

greater in deck width are evaluated as a 2-lane bridge using Table 

2A.

Item 69 - Underclearances, Vertical Horizontal

! This item is calculated by the Edit/Update program and need not be 

coded in the field. Editorial changes have also been made to 

indicate the specifications on which the Edit/Update program is 

based.

! All tables have been converted to metric units of measurement. Where 

appropriate, a hard conversion has been used to match the metric 

standards of AASHTO.

Item 75 - Type of Work

! Segment A code "38" has been expanded to include hydraulic 

replacements.

! In addition to metric changes, editorial additions have been made, 

such as that this item may be left blank if not required.

Item 76 - Length of Structure Improvement

! Formulae for graphs have been added.

Item 92 - Critical Feature Inspection

! Text has been added to give the current guidelines on maximum 

allowable inspection intervals.

Item 94 - Bridge Improvement Cost.

! The examples showing average cost per unit of area have been changed 

to reflect in metric units. The value used is for example only.

Item 97 - Year of Improvement Cost Estimate

!Field expanded to four digits to allow coding of complete year. 

D-8
Item 99 - Border Bridge Structure Number

! Text has been added to clarify the coding.

Item 101 - Parallel Structure Designation

! Clarification of distance between structures coding.

Item 102 - Direction of Traffic

! Text has been added to clarify the coding.

Item 104 - Highway System of the Inventory Route

! With the passage of the 1991 ISTEA, the previous designation of 

highway systems has been eliminated. This item has been changed to 

identify structures that are on inventory routes that are on the 

National Highway System.

Item 105 - Federal Lands Highways

! New item used to indicate special federal lands highways.

Item 108 - Wearing Surface/Protective System

! Wearing surface type code 3 or latex concrete has been modified to 

include "similar" types of additive enhanced concrete, i.e. silica 

fume. 

! A note has been added to the code 0 description of Segment A to make 

it clear that code 0 is to be used if no additional concrete 

thickness or thickness of a wearing surface is included in the bridge 

deck.

Item 110 - Designated National Network

! Consistent with the changes caused by the 1991 ISTEA, the reference 

to the Primary System has been changed to Federal-aid highways.

Item 112 - NBIS Bridge Length

! Bridge length has been defined in metric terms to be structures 

greater than 6.1 meters.

D-9
Item 113 - Scour Critical Bridges

! Two new codes have been added. These are for bridges over "tidal" 

waters and bridges with unknown foundations.

! Text has been added to update guidance and instructions on the scour 

critical coding of bridges over waterways to be in line with an 

October 6, 1993 memorandum on the coding of this item. The subject 

of the memorandum is "NBIS Clarification of Recording and Coding 

Guide - Item 113." The memorandum advises that structures such as 

culverts which have a low risk of scour damage and accordingly 

assessed as stable, are exempt from a scour analysis. Culverts which 

are assessed as low risk may be coded 8, and this includes open 

bottom culverts on competent rock or piles. Open bottom culverts 

with footings on soil should be coded 6 until they have been 

analyzed. The memorandum further states that in considering if a 

bridge is eligible for a code 8, the State shall have completed an 

analysis of a similar bridge with comparable conditions. It is 

recommended that the memorandum be reviewed for more detail.

Item 115 - Year of Future Average Daily Traffic

! Field expanded to four digits to allow coding of complete year. 

! Editorial change made to clarify the coding instructions.

D-10
APPENDIX E

National Bridge Inventory Record Layout
Appendix E

National Bridge Inventory Record Format

With the conversion to metric and the addition of new items it is 

required to expand the size of the NBI record to 432 characters. 

The following format will be use to submit data to the FHWA. 

ITEM ITEM ITEM 

NO ITEM NAME POSITION LENGTH/TYPE

1 State Code 1 - 3 3/N

8 Structure Number 4 - 18 15/AN

5 Inventory Route 19 - 27 9/AN

5A Record Type 19 1/AN

5B Route Signing Prefix 20 1/N

5C Designated Level of Service 21 1/N

5D Route Number 22 - 26 5/AN

5E Directional Suffix 27 1/N

2 Highway Agency District 28 - 29 2/AN

3 County (Parish) Code 30 - 32 3/N

4 Place Code 33 - 37 5/N

6 Features Intersected 38 - 62 25/AN

6A Features Intersected 38 - 61 24/AN

6B Critical Facility Indicator 62 1/AN

7 Facility Carried By Structure 63 - 80 18/AN

9 Location 81 - 105 25/AN

10 Inventory Rte, Min Vert Clearance 106 - 109 4/N

11 Kilometerpoint 110 - 116 7/N

12 Base Highway Network 117 1/N

13 Inventory Route, Subroute Number 118 - 129 12/AN

13A LRS Inventory Route 118 - 127 10/AN

13B Subroute Number 128 - 129 2/N

16 Latitude 130 - 137 8/N

17 Longitude 138 - 146 9/N

19 Bypass/Detour Length 147 - 149 3/N

20 Toll 150 1/N

21 Maintenance Responsibility 151 - 152 2/N

22 Owner 153 - 154 2/N

26 Functional Class Of Inventory Rte.155 - 156 2/N

27 Year Built 157 - 160 4/N

28 Lanes On/Under Structure 161 - 164 4/N

28A Lanes On Structure 161 - 162 2/N

28B Lanes Under Structure 163 - 164 2/N

29 Average Daily Traffic 165 - 170 6/N

30 Year Of Average Daily Traffic 171 - 174 4/N

31 Design Load 175 1/N

32 Approach Roadway Width 176 - 179 4/N

33 Bridge Median 180 1/N

34 Skew 181 - 182 2/N

35 Structure Flared 183 1/N

E-1
ITEM ITEM ITEM

NO ITEM NAME POSITION LENGTH/TYPE

36 Traffic Safety Features 184 - 187 4/AN

36A Bridge Railings 184 1/AN

36B Transitions 185 1/AN

36C Approach Guardrail 186 1/AN

36D Approach Guardrail Ends 187 1/AN

37 Historical significance 188 1/N

38 Navigation Control 189 1/AN

39 Navigation Vertical Clearance 190 - 193 4/N

40 Navigation Horizontal Clearance 194 - 198 5/N

41 Structure Open/Posted/Closed 199 1/AN

42 Type Of Service 200 - 201 2/N

42A Type of Service On Bridge 200 1/N

42B Type of Service Under Bridge 201 1/N

43 Structure Type, Main 202 - 204 3/N

43A Kind of Material/Design 202 1/N

43B Type of Design/Construction 203 - 204 2/N

44 Structure Type, Approach Spans 205 - 207 3/N

44A Kind of Material/Design 205 1/N

44B Type of Design/Construction 206 - 207 2/N

45 Number Of Spans In Main Unit 208 - 210 3/N

46 Number Of Approach Spans 211 - 214 4/N

47 Inventory Rte Total Horz Clearance215 - 217 3/N

48 Length Of Maximum Span 218 - 222 5/N

49 Structure Length 223 - 228 6/N

50 Curb/Sidewalk Widths 229 - 234 6/N

50A Left Curb/Sidewalk Width 229 - 231 3/N

50B Right Curb/Sidewalk Width 232 - 234 3/N

51 Bridge Roadway Width Curb-To-Curb 235 - 238 4/N

52 Deck Width, Out-To-Out 239 - 242 4/N

53 Min Vert Clear Over Bridge Roadway243 - 246 4/N

54 Minimum Vertical Underclearance 247 - 251 5/AN

54A Reference Feature 247 1/AN

54B Minimum Vertical Underclearance 248 - 251 4/N

55 Min Lateral Underclear On Right 252 - 255 4/AN

55A Reference Feature 252 1/AN

55B Minimum Lateral Underclearance 253 - 255 3/N

56 Min Lateral Underclear On Left 256 - 258 3/N

58 Deck 259 1/AN

59 Superstructure 260 1/AN

60 Substructure 261 1/AN

61 Channel/Channel Protection 262 1/AN

62 Culverts 263 1/AN

E-2
ITEM ITEM ITEM

NO ITEM NAME POSITION LENGTH/TYPE

63 Method Used To Determine Operating

 Rating 264 1/N

64 Operating Rating 265 - 267 3/N

65 Method Used To Determine Inventory

 Rating 268 1/N

66 Inventory Rating 269 - 271 3/N

67 Structural Evaluation 272 1/AN

68 Deck Geometry 273 1/AN

69 Underclear, Vertical & Horizontal 274 1/AN

70 Bridge Posting 275 1/N

71 Waterway Adequacy 276 1/AN

72 Approach Roadway Alignment 277 1/AN

75 Type of Work 278 - 280 3/N

75A Type of Work Proposed 278 - 279 2/N

75B Work Done By 280 1/AN

76 Length Of Structure Improvement 281 - 286 6/N

90 Inspection Date 287 - 290 4/N

91 Designated Inspection Frequency 291 - 292 2/N

92 Critical Feature Inspection 293 - 301 9/AN

92A Fracture Critical Details 293 - 295 3/AN

92B Underwater Inspection 296 - 298 3/AN

92C Other Special Inspection 299 - 301 3/AN

93 Critical Feature Inspection Dates 302 - 313 12/AN

93A Fracture Critical Details Date 302 - 305 4/AN

93B Underwater Inspection Date 306 - 309 4/AN

93C Other Special Inspection Date 310 - 313 4/AN

94 Bridge Improvement Cost 314 - 319 6/N

95 Roadway Improvement Cost 320 - 325 6/N

96 Total Project Cost 326 - 331 6/N

97 Year Of Improvement Cost Estimate 332 - 335 4/N

98 Border Bridge 336 - 340 5/AN

98A Neighboring State Code 336 - 338 3/AN

98B Percent Responsibility 339 - 340 2/N

99 Border Bridge Structure Number 341 - 355 15/AN

100 STRAHNET Highway Designation 356 1/N

101 Parallel Structure Designation 357 1/AN

102 Direction Of Traffic 358 1/N

103 Temporary Structure Designation 359 1/AN

104 Highway System Of Inventory Route 360 1/N

105 Federal Lands Highways 361 1/N

106 Year Reconstructed 362 - 365 4/N

107 Deck Structure Type 366 1/AN

108 Wearing Surface/Protective System 367 - 369 3/AN

108A Type of Wearing Surface 367 1/AN

108B Type of Membrane 368 1/AN

108C Deck Protection 369 1/AN

E-3
ITEM ITEM ITEM

NO ITEM NAME POSITION LENGTH/TYPE

109 AVERAGE DAILY TRUCK TRAFFIC 370 - 371 2/N

110 DESIGNATED NATIONAL NETWORK 372 1/N

111 PIER/ABUTMENT PROTECTION 373 1/N

112 NBIS BRIDGE LENGTH 374 1/AN

113 SCOUR CRITICAL BRIDGES 375 1/AN

114 FUTURE AVERAGE DAILY TRAFFIC 376 - 381 6/N

115 YEAR OF FUTURE AVG DAILY TRAFFIC 382 - 385 4/N

116 MINIMUM NAVIGATION VERTICAL 386 - 389 4/N

CLEARANCE VERTICAL LIFT BRIDGE

--- Washington Headquarters Use 392 - 426

STATUS 427

n/a Asterisk Field in SR 428 1/AN

SR SUFFICIENCY RATING 429 - 432 4/N

(select from last 4 positions only)

Status field: 1=Structurally Deficient; 2=Functionally Obsolete; 0=Not 

Deficient; N=Not Applicable

 E-4