Guide for Bridge Curb/Rail and Approach 

Treatment for Extremely Low Volume Roads 

February 9, 2023

FHWA-FLH-23-003a
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

TABLE OF CONTENTS

1 Introduction and Applicability................................................................................................. 5

2 Evaluation Process................................................................................................................... 6

2.1 Key Terms ........................................................................................................................ 6

2.2 Decision Matrices ........................................................................................................... 12

3 Inspecting and Assessing the Existing Conditions ................................................................ 15

3.1 Characterize the Bridge Rail .......................................................................................... 15

3.2 Characterize the Bridge Deck ........................................................................................ 15

3.3 Are Crashworthy Transitions and Terminals Provided? ................................................ 16

3.4 Is Delineation Provided? ................................................................................................ 17

4 Considering Improvements.................................................................................................... 19

4.1 Does Installing a Crashworthy Bridge Rail Meet the Performance Goal? .................... 19

4.2 Is There a Crashworthy Bridge Rail Present? ................................................................ 20

4.3 Can the Existing Bridge Deck Accommodate a Crashworthy Bridge Rail? .................. 21

4.3.1 Top Mounted or Side Mounted Bridge Deck Attachment ...................................... 23

4.3.2 Bridge Fascia Beam Attachment ............................................................................ 23

4.3.3 Other Alternatives ................................................................................................... 25

4.4 Do Crashworthy Transitions and Terminals Meet the Performance Goal? ................... 25

4.5 Is Delineation Needed? .................................................................................................. 26

5 References ............................................................................................................................. 27

Appendix A: Crash Tested Bridge Rail Designs .......................................................................... 28

Appendix B: Crash Tested Bridge Rail Terminal Designs ........................................................... 73

Appendix C: Crash Tested Transition Designs ............................................................................. 92

Appendix D: Inspection Checklist ................................................................................................ 119
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

LIST OF FIGURES

Figure 1. Graphic. Plan view of typical bridge and approaches. .................................................... 8

Figure 2. Graphic. View of major components of a typical bridge. ............................................... 9

Figure 3. Graphic. Low rail height that might promote vaulting or override. ................................ 9

Figure 4. Photograph. Demonstration of measuring Parapet height. ............................................ 10

Figure 5. Graphic. Demonstration of rail pocketing. .................................................................... 10

Figure 6. Photograph. Demonstration of measuring the rail spacing. .......................................... 11

Figure 7. Photograph. Rail lapping, looking downstream in the direction of travel..................... 11

Figure 8. Graphic. Components of the bridge rail that might allow snagging. ............................. 12

Figure 9. Graphic. Step 1 of workflow to determine practical solutions for reducing the risk of 

fatal and serious passenger vehicle collisions. .............................................................................. 13

Figure 10. Graphic. Step 2 of workflow to determine practical solutions for reducing the risk of 

fatal and serious passenger vehicle collisions. .............................................................................. 14

Figure 11. Graphic. Guardrail terminal layout (plan view). ......................................................... 17

Figure 12. Graphics. Compound subfigures illustrating object marker delineation to address 

inspection questions. ..................................................................................................................... 18

Figure 13. Graphics. Compound figures describing types of bridge rail attachments.................. 22

LIST OF TABLES

Table 1. TL selection for bridge rails on roads with ADT ≤ 50 vpd and posted speed ≤ 45 mph. 19

Table 2. Recommended size specifications for bridge components and corresponding post-mount 

design for the fascia mounted bridge rail system.(4) ..................................................................... 24
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

ACRONYMS

ADT average daily traffic 

AASHTO American Association of State Highway and Transportation Officials 

BDS Bridge Design Specification 

FEA finite element analysis 

FHWA Federal Highway Administration 

LRFD Load and Resistance Factor Design 

MASH Manual for Assessing Safety Hardware 

mph miles per hour 

MUTCD Manual on Uniform Traffic Control Devices 

NBI National Bridge Inventory 

NCHRP National Cooperative Highway Research Program 

PL performance level 

RDG Roadside Design Guide 

TL test level 

vpd vehicles per day 
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

1 INTRODUCTION AND APPLICABILITY

This Guide addresses bridge rails, approach guardrails, and transitions on bridges on extremely 

low-volume and low-speed roads. The methodology is applicable to both single- and two-lane 

bridges. For the purpose of this Guide, extremely low-volume roads are defined as roads with 

less than 50 vehicles per day (vpd) and posted speed ranges equal to 5-15 miles per hour (mph), 

16-30 mph, and 31-45 mph. Throughout this Guide the posted and travel speeds on the subject 

bridges are assumed to be equal, and the terms are used interchangeably. The focus of this Guide 

is assessing the need for and practicality of providing bridge rails to contain passenger vehicles 

while accommodating other vehicle types like agricultural equipment, timber harvesting

equipment, recreational vehicles, and other associated service vehicles on the subject bridges. 

This Guide leads inspectors and engineers to practical, low-cost solutions based on the 

characteristics of the bridge, anticipated traffic, and the intended use of the bridge. The outcome 

of using the Guide is the determination of: 

• Whether the existing bridge rails can be left as-is.

• Whether the associated roadside hardware can be left as-is. 

• When improvements should be considered to achieve the safety performance goal. 

• What potential solutions might be implemented to achieve the safety performance goal. 

When new hardware is recommended, the Guide provides construction details for new hardware 

in appendix A, B, and C. An inspection checklist is provided in appendix D that can be used to 

collect the information during the inspection. Evaluating the need to provide roadside barriers, 

such as w-beam for shielding obstacles on the roadside, beyond the approaches to the bridge, is 

beyond the scope of this Guide. 

The Guide follows a two-step process:

1. Inspect and evaluate the existing conditions at the bridge site. 

2. Consider possible improvements to the bridge rails and approach hardware. 
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

2 EVALUATION PROCESS

The first step is to inspect and evaluate the existing bridge rail and any associated hardware. The 

variables and terminology used through this Guide are defined in Section 2.1. The evaluation 

process is guided by the two-part decision matrix discussed in Section 2.2. 

2.1 KEY TERMS 

Key terms used throughout this Guide are defined as follows: 

• BDS: AASHTO Load and Resistance Factor Design (LRFD) Bridge Design 

Specification (BDS).

• Bridge clear width: The shortest clear distance on a bridge between the faces of opposite 

bridge rails or curbs measured in feet. See figure 1. 

• Bridge diaphragm: Bridge diaphragms are transverse stiffeners positioned between the 

bridge girders to restrict lateral movement of the girders under load. See figure 2. 

• Bridge rail: A longitudinal barrier whose primary function is to reduce the risk of an 

errant vehicle going over the side of the bridge structure. See figure 1. 

• Bridge rail system: The bridge rail and its structural mount connection to the bridge 

structure.

• Crashworthy: The crash performance has been successfully evaluated in full-scale crash 

tests (e.g., Manual for Assessing Safety Hardware [MASH], Report 350, etc.), through 

engineering calculations (e.g., AASHTO LRFD Bridge Design Specifications Chapter 

13) and/or finite element analysis (FEA). 

• Continuous bridge rail elements: Bridge rail elements are all spliced together or there is 

one continuous concrete bridge rail. 

• Deck overhang: Distance from the edge of deck to the mount location on the bridge 

fascia beam measured in feet. See figure 2. 

• Delineation: Retroreflective signs and object markers in conformance with the Federal 

Highway Administration’s (FHWA’s) Manual on Uniform Traffic Control Devices 

(MUTCD).

• Drop height: Drop height is the maximum height measured from anywhere along the 

bridge travel surface to the surface (i.e., water or ground) under the bridge. See figure 2. 

• Fascia Beam: An exposed outermost girder/beam/stringer of a bridge span. See figure 2. 

• KA: Fatal and serious injury passenger vehicle crashes based on the KABCO injury 

scale.

• Narrow Bridge: A bridge having a two-way roadway clearance width of 16 to 18 ft, or a 

bridge having a roadway clearance less than the width of the approach travel lanes, or as 

defined by the current edition of the MUTCD. 

• Number of Posts: For post and beam type bridge rails, the number of posts on one travel 

edge of the bridge. 
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

• One-lane bridge: A structure designed for travel in one direction at a given time. A onelane bridge can be on a one-way or a two-way road. 

• Overriding: Overriding is when a vehicle impacts a longitudinal barrier in such a way 

that it goes over the barrier. Overriding is similar to vaulting and is sometimes used 

synonymously but a vehicle overriding a barrier may or may not completely go over the 

barrier. See figure 3.

• Parapet height: The distance from the bridge deck to the top of the parapet. See figure 4. 

• Performance goal: A reduction in the risk of a fatal or serious injury passenger vehicle 

crash to justify implementing a proposed improvement.

• PL: The performance level (PL) used to classify bridge rail crashworthiness prior to the 

introduction of the test level (TL).

• Pocketing: Pocketing is an undesirable behavior of a redirective device like a bridge rail, 

transition, or terminal involving a relatively large lateral displacement within a relatively 

short longitudinal distance. Such behaviors tend to generate large longitudinal 

decelerations as the front of the vehicle contacts a portion of the downstream barrier 

deformed at a sharp angle relative to the vehicle path. See figure 5.

• Post setback: For post and beam type bridge rails, the post setback is the distance from 

the traffic face of the bridge rail to the traffic face of the post as shown in BDS Figure 

A13.1.1-1. See figure 2. 

• Post spacing: The horizontal center-to-center distance of posts.

• Rail height: The distance from the bridge deck surface to the top of the topmost rail of 

the bridge rail. See figure 2. 

• Rail lapping: Guardrail and bridge rail elements are usually lapped in the adjacent 

direction of travel. This means when splicing two panels together, the approach panel is 

placed over the trailing panel such that there are no exposed edges. On a one-way bridge, 

the rail is lapped in the travel direction nearest that edge. See figure 7. 

• Rail spacing: The vertical center-to-center distance of horizontal rail elements if there is

more than one horizontal rail element on a side. See figure 6. 

• Roadway clear width: The shortest perpendicular distance between the edges of travel 

on the approach roadway measured in feet. See figure 1. 

• Snagging: Snagging is contact between a portion of the vehicle and barrier like the 

vehicle tire engaging the side of a bridge rail post. The degree of snagging depends on the 

degree of engagement. Such vehicle-to-barrier engagement can cause large vehicle 

decelerations. See figure 8.

• Terminal: A terminal is a crashworthy anchorage for the transition and/or rail that also 

shields an errant vehicle from the bridge end or rail end. See figure 1. 
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

• TL: The test level (TL) of a bridge rail, transition, or terminal refers to the set of 

conditions used to conduct crash tests including the vehicle type and mass, vehicle impact 

speed and angle. There are six TLs, however this Guide only addresses TL 1 through 3.

• Transition: A section of longitudinal barrier between a terminal or standard rail section 

and a bridge rail. The transition produces a gradual stiffening of the approach rail so that 

vehicle pocketing, snagging, or penetrating at the connection is minimized. See figure 1. 

• Two-lane bridge: A structure designed for travel in two directions at the same time. 

Typically, a bridge that has a clear roadway width greater than 16 ft is considered a twolane bridge. 

• Vaulting: Vaulting is when a vehicle engages with a longitudinal barrier in such a way 

that it is lifted up and over the barrier. The vehicle typically goes completely over the 

barrier. See figure 3. 

Note: This figure shows two travel lanes, however, this Guide is applicable to both one-lane and two-lane bridges. 

Source: FHWA

Figure 1. Graphic. Plan view of typical bridge and approaches.
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

Source: FHWA

Figure 2. Graphic. View of major components of a typical bridge. 

Source: FHWA

Figure 3. Graphic. Low rail height that might promote vaulting or override.
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

Source: FHWA

Figure 4. Photograph. Demonstration of measuring Parapet height. 

Source: FHWA

Figure 5. Graphic. Demonstration of rail pocketing.
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

Source: FHWA

Figure 6. Photograph. Demonstration of measuring the rail spacing.

Source: FHWA

Figure 7. Photograph. Rail lapping, looking downstream in the direction of travel.
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

Source: FHWA

Figure 8. Graphic. Components of the bridge rail that might allow snagging. 

2.2 DECISION MATRICES

Figure 9 and figure 10 provide a workflow to determine practical solutions for reducing the risk 

of fatal and serious passenger vehicle collisions. Figure 9 and figure 10 also reference the 

appropriate sections in this Guide. After initiating the workflow, the first step is to determine if 

there is a crashworthy bridge rail present. If a crashworthy bridge rail is present, the next step is 

to determine if crashworthy transitions and terminals are provided. If it is determined that one or 

more of these items is not present, then the workflow outlines the next steps. 

When a crashworthy bridge rail, transition, or terminal are not present, figure 10 outlines the 

steps to determine if the installation of any of these items would reduce the risk of fatal and 

serious passenger vehicle crashes. When it is determined that providing a crashworthy bridge 

rail, transition, and/or terminal would reduce the risk of serious or fatal crashes, then an 

assessment is made to determine if it is practical to provide these items. 
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

Source: FHWA

Figure 9. Graphic. Step 1 of workflow to determine practical solutions for reducing the risk 

of fatal and serious passenger vehicle collisions. 
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

Source: FHWA

Figure 10. Graphic. Step 2 of workflow to determine practical solutions for reducing the 

risk of fatal and serious passenger vehicle collisions.
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

3 INSPECTING AND ASSESSING THE EXISTING CONDITIONS

3.1 CHARACTERIZE THE BRIDGE RAIL

The first step is to determine if there is a crashworthy bridge rail present. If there is no bridge rail 

present at the existing subject site, go to Section 4.1. When a bridge rail is present, determine the 

answers to the following: 

1. What is the bridge rail height? 

2. Are there parts or components of the bridge rail that might allow snagging on a part of 

the impacting vehicle? If so, what are they? 

3. Are there continuous bridge rail elements from the start to the end of the structure on both 

sides? 

4. If the bridge rail is a post and rail system, does the rail terminate at a post, abutment, or 

anchor block? 

5. What is the drop height? 

6. What is the posted speed limit? If the speed is not posted, what is the estimated travel 

speed?

7. The conditions under the bridge are one of the following: 

A = An ephemeral or intermittent stream channel with water depth less than 6 inches 

during the majority of the time the bridge is in use. 

B = A stream channel with year-round flow or ephemeral/intermittent stream channels 

with water depths greater than or equal to 6 inches for at least 3 months.

Photographs illustrating the answers to each of these questions should be taken to document the 

existing bridge rail and associated hardware. A checklist is provided in appendix D that can be 

used to collect the information from the inspection.

3.2 CHARACTERIZE THE BRIDGE DECK

Document and assess the deck material, condition, and thickness by answering the following 

questions: 

• What is the deck material (e.g., sawn lumber, laminated wood, reinforced concrete, steel, 

etc.)? 

• What is the deck thickness? 

• What is the deck overhang? 

• What is the condition of the deck (i.e., level of deterioration or other damage)? For 

example, if the deck is concrete, is there spalling or exposed rebar? For steel decks, is 

there significant rust and corrosion? For wood decks, is there visible rot or splitting?

• What is the fascia beam material (e.g., sawn lumber, laminated wood, reinforced 

concrete, steel, etc.)? 

• What is the fascia beam size and shape (e.g., W14x30, 6x18, 6 3⁄4 x 18 glulam)? 

• What is the condition of the fascia beam (level of deterioration or other damage)? For a 

concrete beam, is there spalling or exposed rebar? For a steel fascia beam, is there 

significant rust and corrosion? For wood beams, is there visible rot or splitting?

• What is the size and type of bridge diaphragm members? 
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

• What is the size and type of the connector elements, when applicable, that connect the 

diaphragm members to the inside of the fascia beams?

Appendix D includes a checklist that can be used to collect information from the inspection.

3.3 ARE CRASHWORTHY TRANSITIONS AND TERMINALS PROVIDED?

When transitions and/or terminals are present, determine if the terminal and/or transition is 

crashworthy, and its TL based on the following:

1. Documentation (e.g., the original plans and specifications, National Bridge Inventory 

[NBI] data, maintenance records) indicates a crashworthy terminal and/or transition was 

used. 

2. The terminals and/or transitions at the existing site appear to be the same as one of the 

examples shown in appendix B (terminals) or C (transitions). Also determine the TL that 

was used to evaluate the crashworthiness of the transition and/or terminal if 

documentation is available. 

The inspection will answer the following questions: 

1) Is a crashworthy terminal present? 

If yes, please answer the following questions about the transitions:

(a) Is there a transition between the bridge rail and the terminal?

(b) Does the height of the transition at the connection point to the terminal match the 

height of the terminal? 

(c) Does the height of the transition at the connection point to the bridge rail/parapet 

match the height of the bridge rail/parapet? 

(d) Is there a smooth transition in rail height from end-to-end of the transition? 

(e) Does the rail provide a smooth, continuous face to prevent snag points? 

(f) When there are bridge rail posts, are the posts set back from the rail face to minimize 

contact with a vehicle striking the bridge rail? 

(g) Transitions should be structurally attached to the bridge rail and spliced to the 

terminal. Are there secure connections to both the terminal and the bridge rail? 

(h) Is there at least two feet of level fill behind the posts of the transition and the 

terminal?

2) If a terminal is present, take the following measurements (see figure 11): 

(a) Horizontal distance in feet on the approach slope perpendicular to the traveled way 

corresponding to a 1-ft vertical drop. 

(b) Distance from the edge of the shoulder to the change in slope, in feet. Indicate if the 

slope does not change. 

(c) Distance from the back of the first post of the terminal to the change in slope in feet. 
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

(d) Distance in feet from the back of the last guardrail terminal post to the change in 

slope. Indicate if the slope does not change. 

(e) Length in feet of the approach slope taper. Indicate if there is no taper.

(f) Distance in feet from the approach face of the terminal to the end of the approach 

slope taper. Indicate if there is no taper.

Note: There will often be situations encountered where the shoulder width is zero. 

Source: FHWA

Figure 11. Graphic. Guardrail terminal layout (plan view). 

Appendix D includes a checklist that can be used to collect information from the inspection.

3.4 IS DELINEATION PROVIDED? 

Answer the following questions during inspection: 

1) Are Type 3 object markers present at the ends of the bridge (see figure 12)? 

2) If there are terminals, are Type 3 object markers present at the ends of the terminals (see 

figure 12)? 

3) If there are terminals, are OM1-2 object markers present at the ends of the terminals (see 

figure 12)? 

4) What is the bridge clear width?

5) What is the roadway clear width?

6) Is the approach roadway two-way?

7) Is a narrow bridge sign (W5-2) provided (see figure 12)? 

8) Is a one lane bridge sign (W5-3) provided (see figure 12)? 

Appendix D includes a checklist that can be used to collect information from the inspection.
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

Source: FHWA

A. Subfigure Type 3 marker. 

Source: FHWA

B. Subfigure OM1-2 marker.

Source: FHWA

C. Subfigure one-lane bridge sign (W5-3) on 

a bridge. 

Source: FHWA

D. Subfigure narrow bridge sign (W5-2) on a 

bridge. 

Figure 12. Graphics. Compound subfigures illustrating object marker delineation to 

address inspection questions.
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

4 CONSIDERING IMPROVEMENTS

4.1 DOES INSTALLING A CRASHWORTHY BRIDGE RAIL MEET THE PERFORMANCE GOAL? 

The second step in the process is to consider potential safety improvements to the bridge rail or 

associated hardware. Use this section to determine whether a crashworthy bridge rail is 

appropriate at the site. 

If a bridge rail is found to be appropriate and there is an existing rail present, determine if the 

existing rail is crashworthy based on Section 4.2. If there is no existing crashworthy rail present 

and, through this section of the Guide, it is determined a bridge rail is appropriate, proceed to 

Section 4.3.

Given the posted speed limit, under-bridge condition (e.g., A or B), and drop height, determine 

what TL is appropriate from table 1. The conditions in table 1 should result in a reduction in the 

risk of a passenger vehicle KA crash compared to not having a bridge rail at all. Notice that 

bridges 20 ft or less above an ephemeral or intermittent stream (i.e., Condition A) on a road with 

a posted speed limit of 15 mph or less do not meet the goal, therefore, a bridge rail is not 

necessary. 

Table 1. TL selection for bridge rails on roads with ADT ≤ 50 vpd and 

posted speed ≤ 45 mph.

Posted 

Speed 

Limit 

(mph)

Dry Environment Under Bridge 

(Condition A)

Water Under Bridge 

(Condition B)

Drop Height - H (ft)

H ≤ 20 20 < H ≤ 50 H > 50 H ≤ 20 20 < H ≤ 50 H > 50 

5 - 15 NRB 12-in curb rail or TL-1 

16 - 30 TL-1 or higher bridge rail

31 - 45 TL-2 or higher bridge rail

Note: Surface condition under bridge: 

A = An ephemeral or intermittent stream channel with water depth less than six inches during the majority 

of the time the bridge is in use. 

B = Any stream channel with year-round flow or ephemeral or intermittent stream channels with water 

depths greater than or equal to six inches for at least three months.

NRB =Not risk beneficial.

Where it is determined appropriate to install a bridge rail, proceed to Section 4.3.

Refer to appendix A for a variety of crashworthy curb rails, TL1, and TL2 bridge rails. Over 

time, it is expected that additional bridge rails will be developed that will meet the MASH TL1 

and TL2 requirements. These may be used as they become available.
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

4.2 IS THERE A CRASHWORTHY BRIDGE RAIL PRESENT? 

If a bridge rail is present at the existing site, determine if the bridge rail crash performance has 

been verified based on one of the following: 

• The original construction plans or specifications, NBI data, or maintenance and repair 

records are available and indicate the bridge rail was evaluated by full-scale crash testing. 

• Documentation is available showing that the bridge rail is crashworthy based on 

engineering calculations (e.g., AASHTO LRFD, BDS, and/or FEA). 

• When documentation of the bridge rail is not available, compare the inspection 

photographs of the bridge rail with the systems tabulated in appendix A. If the bridge rail 

matches one of the bridge rails in appendix A it can be assumed to be crashworthy.

From the same sources, also determine the TL that was used to evaluate the crashworthiness of 

the bridge rail (e.g., NCHRP Report 350 or MASH TL1, TL2, etc.). If the crashworthiness of the 

bridge rail could not be determined using one of the three methods listed above, then an 

engineering analysis may be performed using the procedures outlined in Section 13 of the 

BDS.(3) The evaluation procedures include assessment criteria for verification as follows: 

1. The bridge rail height meets the BDS specifications (i.e., Table A13.2.-1 or BDS 

13.7.3.2). 

2. The bridge rail geometry and anchorage meet the criteria specified in BDS A13.1. 

3. The design capacity meets or exceeds the values in BDS Table A13.2-1 for the 

appropriate TL (i.e., TL1 or TL2). 

o For concrete rails see BDS Section A13.3.1. 

o For steel post-and-beam rails see BDS Section A13.3.2. 

o For concrete parapet and metal rail see BDS Section A13.3.3. 

o For wood barriers see BDS Section A13.3.4. 

A minimum rail height of 27 inches is specified for TL1 bridge rails in BDS Table A13.2-1; 

however, it does not take into consideration the lower-profile rails that have been shown to meet 

NCHRP Report 350 TL1 or MASH TL1 (see appendix A) performance criteria. Thus, if a TL1 

bridge rail design is less than 27 inches tall and has not been tested for TL1, then it is 

recommended that the crash performance be evaluated through full-scale crash testing or FEA. 

Assess the potential for vehicle snagging on the bridge rail posts based on post set-back from the 

face of rail, open space between rails, and contact area on face of barrier (post-and-beam designs 

only). The vertical clearance and post setback should plot in the preferred area of BDS Figure

A13.1.1-2. The ratio of rail width to rail height and setback should also plot in the preferred area 

of BDS Figure A13.1.1-3. 

If the existing bridge rail is determined to be crashworthy according to any of the methods 

discussed in this section, stop, and proceed to Section 4.4. If the bridge rail is not crashworthy 

and a bridge rail was found to be appropriate for this location through Section 4.1, then proceed 

to Section 4.3. 
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

4.3 CAN THE EXISTING BRIDGE DECK ACCOMMODATE A CRASHWORTHY BRIDGE RAIL? 

If new bridge construction or replacement is not planned, then the existing bridge conditions 

must be assessed to determine if the bridge structure can support the design loads for a 

crashworthy bridge rail when such a rail would meet the performance goal. The effectiveness of 

a bridge rail is dependent upon the structural integrity of the bridge structure to which it is 

attached. In other words, the mounting point on the bridge structure must be capable of 

supporting the design impact loads (e.g., moment, shear, bearing, etc.) for the bridge rail. The 

strength of the mounting point on the bridge structure is dependent on the type of material 

(e.g., laminated timber, concrete, steel, etc.) as well as the thickness and condition of the material 

(e.g., deterioration) to which the bridge rail is mounted. 

When detailed drawings and/or design information for the bridge are available, that information 

may be used to determine the structural adequacy of the bridge deck and structure for resisting 

the impact loads associated with a bridge rail collision. When the existing design details are not 

available, observations and measurements taken during the inspection are used in properly 

categorizing the existing bridge structure for structural adequacy. Depending on the age of the 

bridge, it may also be necessary for an inspector to assess the condition of the bridge structure 

(e.g., deck and/or fascia beam) to evaluate the level of deterioration, wear, or damage. 

Most of the existing bridge rails on extremely low-volume bridges are mounted directly to the 

bridge deck using either a top-mounted or a side-mounted bridge rail design, while other designs 

involve mounting to the bridge fascia beam. Figure 13 illustrates these various rail attachments. 

If the strength of the existing bridge deck is equivalent to, or greater than, the strength of the 

deck for the rails shown in appendix A, then the existing deck can be considered suitable for that 

particular bridge rail design. 
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

© RoadSafe

A. Subfigure top mounted deck 

attachment. 

© RoadSafe

B. Subfigure side mounted deck 

attachment. 

© RoadSafe

C. Subfigure fascia beam attachment 

(without overhang). 

© RoadSafe

D. Subfigure fascia beam attachment (with 

overhang). 

Figure 13. Graphics. Compound figures describing types of bridge rail attachments.

Article A13.4 of the AASHTO LRFD BDS provides assessment criteria for the bridge deck 

overhang for supporting transverse, longitudinal, and vertical design forces for bridge rail. The 

forces that are to be transmitted from the bridge rail to the bridge deck may be determined from 

an ultimate strength analysis of the bridge rail using the design loads defined in BDS Table 

A13.2-1. 
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

4.3.1 Top Mounted or Side Mounted Bridge Deck Attachment

The majority of post-and-beam bridge rail designs are mounted directly to the top of the bridge 

deck surface using through bolts. These cases also include side-mounted bridge rail designs 

which use mounting brackets bolted directly through the top of the deck. Some timber rail 

designs use a combination mount design involving a mounting bracket bolted directly through 

the top of the deck as well as a side-mount connection (e.g., bolted or nailed to the side of the 

deck). The latter case is commonly used on longitudinal-laminate timber bridge decks. For the 

top-mounted designs listed in appendix A, the MASH compliance tests were performed on 

timber decks with thicknesses of 5 – 8 inches or on concrete decks with thicknesses of 7.25 – 8 

inches. 

4.3.2 Bridge Fascia Beam Attachment

In some cases, it may be necessary or desirable to use a bridge rail system that mounts to the 

fascia beam of the bridge superstructure rather than the deck. This approach could be considered 

when it is determined that the existing bridge deck cannot support the design loads for available 

bridge rail designs, but the fascia beam can.

Many bridges on local road systems use steel superstructures to support various deck types 

(e.g., timber boards, asphalt filled steel stay-in-place forms, fiber reinforced composite, etc.) 

where the deck may not be able to support a bridge rail. The bridge rail systems typically 

installed on these bridges are steel-post-and-beam designs mounted directly to the steel fascia 

beam of the bridge superstructure. Most of these designs have not been crash tested, although the 

crash performance of at least one design was evaluated to Report 350 TL3 using FEA. That 

particular bridge rail design is a steel two-tube bridge rail, shown in appendix A, that is 

applicable to bridge structures meeting the size specifications for the bridge components, as 

defined in table 2, and for deck thicknesses less than 8 inches.
Table 2. Recommended size specifications for bridge components and corresponding post-mount design for the fascia mounted 

bridge rail system.(4)

Fascia Beam Diaphragm WT Connector Mounting Tube

PostStiffener 

Min. Size Design

Min. Thickness 

Min. 

Size

Min. Thickness 

Min. 

Size

Min. Thickness

Min. 

Size

Min. 

Thickness 

(in)

Max. 

Length 

(in) Flange 

(in)

Web 

(in)

Flange 

(in)

Web 

(in)

Flange 

(in)

Web 

(in)

W14x30 and 

larger W14 

sections

0.385 0.27 C12x

25 0.501 0.387 WT6x36 0.67 0.43 TS12x6x0.25 0.25 15 

B 

(horz. 

Plates)

W16x40 and 

larger section 

sizes

0.505 0.305 C12x

25 0.501 0.387 WT6x36 0.67 0.43 TS14x6x0.25 0.25 15 

B 

(horz. 

Plates)
In cases where the existing bridge structure is not the same as that for which the bridge rail was 

designed and crash tested, then engineering analysis may be used to determine if the existing 

structure can support the bridge rail. If the bridge structure cannot support the design loads 

defined in BDS Table A13.2-1, then it may be necessary to strengthen the bridge superstructure 

at the mount locations (e.g., add gussets or plates, increase size of diaphragm elements, etc.) or to 

redesign the mount to distribute the loading more effectively over a larger area of the fascia 

beam. 

4.3.3 Other Alternatives

If it is determined that the bridge structure cannot support the design loads defined in BDS Table 

A13.2-1 for the available crashworthy bridge rail designs but a crashworthy bridge rail is 

appropriate to meet the performance goal, then the bridge owner may choose to rehabilitate, 

strengthen, or replace the bridge structure to accommodate the bridge rail. Provided the deck 

strength is equal to or greater than those deck strengths shown in appendix A, then variations in 

the deck would be considered inconsequential to the crash performance of the rail provided there 

were no other changes made to the selected bridge rail (e.g., overall system height, railing type, 

railing position, post type, post spacing, etc.).(4, 5) 

BDS Section 13.7.3.1.2 indicates that provisions be made to transfer design loads from the 

railing system to the bridge structure based on load requirements specified in BDS Table A13.2-

1. The BDS further specifies that for concrete decks, the minimum deck thickness at the bridge 

rail connection point must be: 

• 8 inches – for concrete deck overhangs supporting either a deck-mounted post-and-beam 

bridge rail or concrete parapet. 

• 12 inches – for side-mounted bridge rails. 

4.4 DOES INSTALLING CRASHWORTHY TRANSITIONS AND TERMINALS MEET THE 

PERFORMANCE GOAL?

The result of this section will be a determination about the appropriateness of providing

crashworthy approach guardrail terminals and transitions. If the posted speed limit is 30 mph or 

less and the rail is terminated at a post when a post and rail bridge rail system is used, the 

installation of new terminals and/or transitions is generally not risk beneficial and no further 

analysis is necessary before proceeding to Section 4.5. If the posted speed limit is greater than 30 

mph, the installation of terminals and transitions are risk beneficial, so continue with this section 

before proceeding to Section 4.5. 

Consider installing crashworthy terminals and transitions on bridge approaches where the posted 

speed limit is greater than 30 mph. Refer to appendix B and C for a selection of crashworthy 

terminals and transitions. Over time, it is expected that additional terminals and transitions will 

be developed, and they may be used as they become available. For guidance about the grading 

around the terminal, see RDG Section 8.3.3 and Figures 8.2 and 8.3. 

If there is insufficient distance from the intersecting roadway to the bridge to accommodate the 

transition and terminal, lower the posted speed limit to 30 mph, delineate the bridge in 

accordance with Section 4.5 of this Guide, and terminate the rail at a post when a post and rail 

bridge rail system is used.
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

4.5 IS DELINEATION NEEDED?

Reference the current edition of the MUTCD Sections 2C.63, 2C.64, and 2C.65 for guidance on 

the necessity of delineation of bridge structures and railing systems with object markers. Provide 

Type 3 object markers or OM1-2 object markers as required.

When the bridge clear width is less than that of the approach roadway clear width, provide a 

narrow bridge sign (W5-2) in accordance with the MUTCD Section 5C.05. 

When the bridge carries a two-way roadway and has a bridge clear width of 16 to 18 ft, provide a 

narrow bridge sign (W5-2) in accordance with the MUTCD Section 2C.20. 

When the approach roadway carries a two-way roadway and there is a bridge clear width of less 

than 16 ft, provide a one-lane bridge sign (W5-3) in accordance with Section 2C.21 of the 

MUTCD. 
Task 6: Final Guide

5 REFERENCES

1. Ray MH. Development of Safety Performance Based Guidelines for the Roadside Design 

Guide [Project]. Washington, D.C.: Transportation Research Board, National Cooperative 

Highway Research Program; 2021 Expected. Contract No.: NCHRP 15-65. 

2. AASHTO. Roadside Design Guide. 4th ed. AASHTO, editor. Washington, D.C: American 

Association of State Highway and Transportation Officials; 2011. 

3. AASHTO. AASHTO LRFD Bridge Design Specifications. Eighth Edition ed. Washington, 

D.C.: American Association of State Highway and Transportation Officials; 2018. 

4. Plaxico CA, Johnson TO. Design and Evaluation of a Fascia Mounted Bridge Rail for Steel 

Bridges on Local Roadways. International Roadside Safety Conference; June 2017; San 

Francisco, CA: Tranportation Research Board; 2017. 

5. Plaxico CA, editor Designing a TL-3 Bridge Guardrail System Mounted to Steel Fascia 

Beams for use on Ohio’s Local System. 70th Ohio Transportation Engineering Conference 

(OTEC); 2016 October 24-26, 2016; Columbus, OH. 
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

APPENDIX A: CRASH TESTED BRIDGE RAIL DESIGNS
Appendix A. Crash Tested Bridge Rail Designs 

System 

Name 

Test 

Number 

Test 

Level Photo/Sketch 

Deck Rail 

Ref 

Type Thick 

(in) Type Mount Height (in) 

West 

Virginia 

Curb-Type 

Bridge Rail 

WVBR-1 

MASH 

TL-1 

Nail 

laminated 

timber 

5.50 

Curb-type 

timber post 

and beam. 

Bolted through 

rail, post, & 

deck, nut 

secured under 

deck. 

19.75 1 

Timber 

Curb-Type 

Bridge 

Railing for 

Low 

Volume 

Roads 

CTBR-1 

R350 

TL-1 

2” 

Bituminous 

wearing 

surface on 

top of 

longitudinal 

glulam 

timber 

10.75 

Single glulam 

timber post 

and timber 

beam. 

Top bolted 

through top of 

rail, post, & 

deck with (4) 

3/4”Ø A307 

bolts. 

17.75 2 

Timber 

Bridge Rail 

System 

One 

7212-4 7212-5 

PL-1 

2” wearing 

surface on 

top of 

Glulam 

timber 

6.75 

Glulam rail, 

timber block, 

and timber 

post. 

Post seated in 

steel bracket, 

bracket bolted 

to u-shape 

fastener with 

(4) 3/8”x2.5”L

fillet welds, ushape fastener

bolted to

top/bottom of

bridge deck

with (4) 3⁄4”Ø

A325 bolts.

27.00 3 
System 

Name 

Test 

Number 

Test 

Level Photo/Sketch 

Deck Rail 

Ref 

Type Thick 

(in) Type Mount Height (in) 

Wood 

System – 

Bridge 

Railing 

WRPB-1 

R350 

TL-2 

2” concrete 

wearing 

surface on 

top of 

transverse 

glulam 

timber 

5.125 

Single glulam 

timber rail, 

timber 

blockout, and 

timber posts. 

Angle brackets 

bolted through 

top/bottom of 

the timber 

portion of the 

bridge deck 

with (6) 7/8”Ø 

bolts. 

28.40 4 

TxDOT 

T631 

Bridge Rail 

490023-6-1a

490023-6-2 

MASH 

TL-2 

Concrete 

(4000 psi) 8.00 

W-beam

attached to

steel posts.

Base plate 

bolted through 

bridge deck 

with (4) 5/8”Ø 

10”L A325 

bolts. 

31.00 5 

Single 

Longitudinal 

Glulam 

Bridge 

Railing 

(Shoe-Box 

System) 

FSSB-1 FSSB-2 

PL-1 

Glulam 

timber 10.75 

Single glulam 

rail attached to 

sawn timber 

blockout and 

timber post. 

Post seated in 

metal “shoebox” and 

tacked with 6”L 

nail spike. 

Shoe-box 

through bolted 

into bridge 

deck with (2) 

1”Ø x 48”L 

A722 highstrength 

threaded rods. 

32.00 6 
System 

Name 

Test 

Number 

Test 

Level Photo/Sketch 

Deck Rail 

Ref 

Type Thick 

(in) Type Mount Height (in) 

Low-Cost, 

Energy 

Absorbing 

Bridge Rail 

MGSBR-1 MGSBR-2 

MASH TL-3 

4000 psi 

concrete 8.00 

W-beam rail

attached to

steel posts

with back-up

plates.

Side mounted 

using a weak 

post assembly 

through bolted 

(top-bottom) 

with 1”Ø bolt. 

31.00 7 

SquareShape 

Timber 

Curb Rail 

LVCS-4 

R350 

TL-1 

2” 

Bituminous 

wearing 

surface on 

top of 

longitudinal 

glulam 

timber 

10.75 

Single timber 

beam and 

timber post. 

Top bolted 

through top of 

rail, post, & 

deck with (2) 

5/8”Ø A307 

bolts. 

12.00 8 

Modified 

12-inch

bridge rail

for plank

deck

4” x 12” 

Timber 

Planks 

3.50 

Curb-type 

timber post 

and beam. 

Bolted through 

rail, post, & 

deck, nut 

secured under 

deck. 

12.00 9 

Modified 

19.75-inch 

bridge rail 

for plank 

deck 

MASH TL-1 

4” x 12” 

Timber 

Planks 

3.50 

Curb-type 

timber post 

and beam. 

Bolted through 

rail, post, & 

deck, nut 

secured 

through 4” x 

12” stiffener 

plate under 

deck. 

19.75 10
 

 

 

 

 

 

 

 
 

 

 

 

 

 

 

 

 

 

 

 

 
 

 

 

 

 

 

  

 
 

 

 

 
 

 

 

 

 

 

 
 

 

 

 
 

 

 

 

 

 

 

 

 
 

 

 

 
 

 

 

 

 

 

 

 

 
 

 

 

 

 
 

 

 

 

 
 

 

 

 

 

 
 

 

 

 

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
 

 

 

 

 

 

 

 
 

 

 
 

 

 

 

 

 

 
 

 

 
 

 

 
 

 

 

 

 

 

 

 
 

 

 

 

 
 

 
 

 

 

 

 
 

 

 

 

  

 

 
 

 

 

 

 

 

 
 

 

 

 

 

 

 

 
 

 

 
 

 
 

 

 

 

 

 

 
 

 

 

 
 

 

 

 

 

 

 

 

 

 

 
 

 

 
 
 

 
 

   

 

 

 

 

 
 
 

 

 

 

 

 

 

 
 

 

 

 

 

 

 

 

 

 
 

 

 

 

 

 

 

 

 
 

 

 

 

 

 

 

 

 
 

 

 

 

 
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

APPENDIX B: CRASH TESTED BRIDGE RAIL TERMINAL DESIGNS
Appendix B. Crash Tested Bridge Rail Terminal Designs 

System 

Name 

Test 

Number 

Test 

Level Photo/Sketch Downstream Connection 

Terminal 

Ref 

Type End Height 

(in) 

Vermont 

G1-d 

W-beam

Terminal

47380-2 47380-3 47380-4 

R350 

TL-2 

W-beam /

W-beam

transition

W-beam rail

with steel

blocks and

steel posts

W-beam radius

with buffer end

(Radius=15.75’)

27.00 1 

NETCMELT 

Guardrail 

End 

Terminal 

400401-1 400401-2 

R350 

TL-2 

W-beam /

W-beam

transition

W-beam rail

with wood

blocks and

wood posts

Flared W-beam 

with buffer end 

(Flare=4’) 

27.00 2 

Steel 

Backed 

Timber 

Guardrail 

Tangent 

End 

Terminal 

09005 09006 09008 09009 

R350 

TL-2 

Steel Backed 

Timber 

Barrier 

Timber rail 

with timber 

blocks and 

timber 

breakaway 

posts in 

steel tubes 

90-degree blunt

end of timber rail

and post

27.00 3 
 

 

 
 

 

 

 

 

 

 

 

 
 

 

 

 

 

 
 
 
 

 
 

 

 

  

 

 

 

 
 

 

 

 

 
 

 
 

 

 

 

 

 
 

 

 

 
 

 

 

 

 

 

 

 

 

 

 
 

 

 

 

 

 

 

 
 

 

 
 

 

 

 

 

 
 

 

 

  

 

 
 

 

 

 

 

 

 

 

 

 

 
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

APPENDIX C: CRASH TESTED TRANSITION DESIGNS 
Appendix C. Crash Tested Transition Designs 

System 

Name 

Test 

Number 

Test 

Level Photo/Sketch 

Guardrail Transition Bridge Rail 

Ref 

Type Type Post Connection Type 

Steel 

System 

Approach 

Guardrail 

Transition 

STCR-2 

R350 TL-2 

27.78” tall 

standard 

w-beam

guardrail.

Symmetrical 

transition 

section to 

12’6” thrie 

beam 

section. 

Seven steel 

posts with 

wood 

blockouts 

installed @ 

37.5” 

spacing 

embedded 

49”-54” 

deep.

Typical thrieto-thrie beam 

splice using 

(12) 5/8”Ø

bolts and cap

rail transition

using (2)

5/8”Ø bolts.

31.65” tall 

thrie beam 

with steel 

channel cap 

rail. 

1 

Wood 

System 

Approach 

Guardrail 

Transition 

WRBP-2 

R350 TL-2 

27.78” tall 

standard 

w-beam

guardrail.

W-beam

guardrail

(reduced

post spacing)

to nested wbeam

guardrail.

Seven steel 

posts with 

wood 

blockouts 

installed @ 

37.5” 

spacing 

embedded 

43”-55” 

deep.

W-beam

terminal

connector

and

transition

splice plate

with (8)

7/8”Ø A307

bolts.

28.4” tall 

glulam 

timber 

bridge rail. 

2 

W-Beam

Retrofit

Transition

472070-3 472070-4 

R350 TL-2 

27” tall 

standard 

w-beam

guardrail

- G4(1S).

Nested wbeam 

guardrail with 

steel channel 

rub rail. 

Three steel 

posts with 

steel 

blockouts 

installed with 

(2) @ 37.5”

spacing and

(1) @ 6’3”

spacing

embedded

50” deep.

Typical w-tow beam 

splice using 

(8) 5/8”Ø

bolts and rub

rail using (2)

5/8”Ø bolts

and (4) 7/8”Ø

DFS wedge

anchors.

29” tall wbeam 

retrofit 

bridge rail, 

supported 

by wood 

posts, and 

backed by 

concrete 

rail 

3 
System 

Name 

Test 

Number 

Test 

Level Photo/Sketch 

Guardrail Transition Bridge Rail 

Ref 

Type Type Post Connection Type 

West 

Virginia 

Timber 

Bridge 

Rail 

Transition 

(Timber 

Bridge 

Rail 

System 2) 

7212-3 

AASHTO PL-1 

None 

installed, 

report 

assumed 

6’3” post 

spacing 

on 

standard 

guardrail 

section. 

Glulam rail 

with timber 

rub rail. 

Glulam 

stiffening rail 

installed on 

last 4 posts 

of transition 

and first 2 

bridge rail 

posts. 

Ten wood 

posts with 

wood blocks 

installed with 

(4) @18.75” 

spacing, (4) 

@37.5” 

spacing and 

(1) @6’3” 

spacing 

embedded 

44” deep. 

Glulam 

transitionbridge rail 

spliced using 

(4) 7/8”Ø 

bolts through 

transition rail, 

block, post, 

and stiffening 

rail. Rub rail 

splice using 

(2) 5/8”Ø 

bolts and 

bolted to the 

deck using 

(4) 7/8”Ø 

bolts. 

27” tall wbeam over 

steel tubes 

with timber 

blocks and 

posts 

seated in a 

steel 

bracket. 

4 
 

 

 

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
 
 

 

 

 
 

 

 

 

 

 
 

 
 

 

 

 

 
 

 

 

 

 
 

 

 

 

 
 
 

 
 

 

 

 

 

 

 

 

 
 
 

 
 

 

 

 
 

 

 

 
 

 

 

 

 

 
 

 

 

 

 

 

  

 

 
 

 

  

 

 

 
 

 

 

 

 

 
 

 

 
 

 

 

 

 

 

 

 

 

 

 

 

 
 

 

 

 

 

 
 

 

 

 

 

   

 

   

 

 

 
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

APPENDIX D: INSPECTION CHECKLIST

An inspection checklist for use in collecting the suggested on-site data is provided in the next 

pages. User agencies may modify and change this checklist to meet their own needs and local 

circumstances.
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

Low-Speed, Low-Volume Bridge Rail Inspection Checklist

This checklist can be used to collect information to assess the need for bridge rails and approach 

hardware on bridges on roads with posted speed limits of 45 mph or less and ADT volumes of 50 

vpd or less. 

Characterizing the Bridge Rail Photograph 

Included?

The bridge rail height is: inches 

The posted speed limit is: mi/hr 

The average annual daily traffic is: vehicles/day 

The drop height from the bridge deck to 

the ground or water surface below is:

ft

The condition under the bridge is:

  An ephemeral or intermittent stream with water depth less than 6

 inches during the majority of time the bridge is in use. 

  Any live stream channel with year-round flow or ephemeral or

intermittent stream channels with water depths greater than or equal 

to 6 inches for at least 3 months.

  Other:

There is potential for a passenger vehicle 

overriding or vaulting the bridge rail: 

 Yes

 N

Explain: 

There are parts or components of the 

bridge rail that might snag on a passenger 

vehicle:

 Yes

 N

Explain: 

The rail element is not continuous from 

the beginning to the end of the bridge: 

 Yes

 N

Explain: 

The rail element at the ends of the bridge 

terminate at a post, abutment, or anchor 

block: 

 Yes

 N

Explain: 
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

Characterizing the Bridge Deck Photograph 

Included?

The deck material is:

Material Condition

□ Wood □ Good □ Poor: □ Rotten □ Splits

□ Glue laminated wood □ Good □ Poor: □ Rotten □ Splits

□ Reinforced concrete □ Good □ Poor: □ Spalling □ Exposed bars 

□ Steel □ Good □ Poor: □ Extensive rust/corrosion

□ Other: ____________□ Good □ Poor 

The bridge deck thickness is: inches 

The bridge deck overhang is: ft

The fascia material and condition are:

 Material Condition

□ Wood □ Good □ Poor: □ Rotten □ Splits

□ Glue laminated wood □ Good □ Poor: □ Rotten □ Splits

□ Reinforced concrete □ Good □ Poor: □ Spalling □ Exposed bars 

□ Steel □ Good □ Poor: □ Extensive rust/corrosion

□ Other: ____________□ Good □ Poor 

The fascia beam size/shape is: 

The bridge diaphragm elements material and condition are:

 Material Condition

□ Wood □ Good □ Poor: □ Rotten □ Splits

□ Glue laminated wood □ Good □ Poor: □ Rotten □ Splits

□ Reinforced concrete □ Good □ Poor: □ Spalling □ Exposed bars 

□ Steel □ Good □ Poor: □ Extensive rust/corrosion

□ Other: ____________□ Good □ Poor 

______________________________________________________ 

The bridge diaphragms size/shape are: 

Size and type of connector elements 

connecting diaphragm elements to the 

fascia beam:
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

Characterizing transitions and terminals Photograph 

Included?

Distance to the nearest intersecting roadway in the 

primary approach direction. ft 

Distance to the nearest intersecting roadway in the 

primary trailing end direction. ft 

Distance to the nearest intersecting roadway in the 

opposing approach direction. ft 

Distance to the nearest intersecting roadway in the 

opposing trailing direction. ft 
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

The following are provided (check all that apply): 

Primary Terminal  Transitio   Structural attachment to the bridge ra

Approach: 

Primary:  Terminal  Transitio   Structural attachment to the bridge ra

Trailing End: 

Opposing Terminal  Transitio   Structural attachment to the bridge ra

Approach: 

Opposing Terminal  Transitio   Structural attachment to the bridge rai.  Trailing En

There are parts or components 

of the transitions that might 

snag on a passenger vehicle:

 Yes

 N

Explain: 

There are parts or components 

of the terminals that might snag 

on a passenger vehicle:

 Yes

 N

Explain: 

Note: Plan view, not to scale

If an approach guardrail terminal is present, measure the following:

(Where Values are referenced below, refer to diagram above) 

(a) Horizontal distance in feet on the approach slope perpendicular to 

the traveled way corresponding to a 1-ft vertical drop. (Value a) ft

(b) Distance from the edge of the shoulder to the change in slope. 

 Not applicable. The slope does not change. (Value b

ft

(c) Distance from the back of the first post of the terminal to the change 

in slope. (Value c) ft

(d) Distance in feet from the back of the last guardrail terminal post to 

the change in slope. 

  Not applicable. The slope does not change. (Value d

ft
Guide for Bridge Curb/Rail and Approach Treatment for Extremely Low Volume Roads 

(e) Length in feet of the approach slope taper. 

  Not applicable. There is no taper

ft

(f) Distance in feet from the approach face of the terminal to the end of 

the approach slope taper. 

  Not applicable. There is no taper

ft

Characterizing the Delineation Photograph 

Included?

The roadway clear width is: ft

The bridge clear width is: ft

The approach roadway has traffic in  one  two direction

Are MUTCD Type 3 object markers 

provided? 

 Yes

 No

Are MUTCD OM1-2 object markers 

provided? 

 Yes

 No

Are MUTCD W5-3 signs provided?  Yes

 No

Are MUTCD W5-2 signs provided?  Yes

 No