US. Deportmenl Memorandum 

o( icnsporto1ion 

Federal Highway 

Administration 

Subject: Date: MAY 2 6 2015 

From: In Reply Refer To: 

IISST 

To: Division Administrators 

Federal Lands Division Engineers 

Safety Field 

Purpose 

The purpose or this memorandum is to bring to your attention two primary issues related 

to guardrail end terminals that \~ II require you to take action. As you are aware. we have 

been closely examining the performance or guardrail end terminals. It's recognized that 

there are installation and maintenance challenges with these devices. As the construction 

season starts. and after the heavy winter. this is the appropriate time to pay particular 

attention to installation and maintenance issues. In this memo, Fll W A emphasizes the 

need to have in place policies and procedures to evaluate the selection or roadside safety 

hardware relati ve to the roadway type. configuration and tcrTain: ensure its proper 

installation and maimenance: and periodically evaluate its in-service condition. ln 

addition. we arc aware lhere are some obsolete, non-crashworthy guardrail end terminals 

that still exist on the nation's highway system. We have raised awareness regarding these 

terminals through previous memoranda issued over a number or years. We strongly 

recommend that you encourage the removal or pre-NCHRP-350 guardrail end tenninals. 

Background 

It is FHWA policy that roadside safety hardware installed on the National Highway 

System (NHS) should be in compliance with the crash testing and evaluation criteria 

contained in the Manual for Assessing Safety Hardware (MASH) or its predecessor the 

National Cooperati ve Highway Research Program (NCHRP) Report 350. Devices that arc 

compliant with either of these two sets or criteria are currently considered crash worthy 

devices. 

It is critical that devices be installed and maintained properly so they arc in the best 

position to perform as designed and tested. Attached is a technical brief titled "Selection, 

Installation, and Maintenance of W-bcam Guardrail End Terminals'' which highlights 

general guidelines regarding U1e selection, installation. and maintenance of W-beam 
guardrail end terminals. In addition, common issues of concern are identified with 

generally accepted practices to address these concerns. 

Even when a successfully crash tested device is properly selected, installed, and 

maintained, individual crashes in the field are unique events and may result in 

performance that was not observed during crash testing. For this reason, a crash tested 

device should be monitored for its in-service performance, as indicated in both NCHRP 

350 and MASH. 

2 

It is known that roadside safety hardware installed prior to the implementation ofNCHRP 

350 in 1993 remains on the NHS or other roadways across the nation. However, as 

indicated in the FHW A action memorandum, "Traffic Barrier Safety Policy and 

Guidance," dated 9/29/1994, non-crashworthy hardware should be removed and replaced 

with crashworthy roadside hardware at the earliest possible opportunity in concert with 

the maintenance of the roadway. It has been more than twenty years since that memo was 

issued and devices listed in that memo are still in service. We strongly recommend that 

pre-NCHRP 350 guardrail end terminals be removed and replaced. 

Action 

Please share this memorandum and its enclosure with your State DOT and any city, 

county or municipality in your State with responsibility for the operation and maintenance 

of their roadways. 

Please ask them to review and, if necessary, update their policies, procedures, standards, 

and guidelines relative to the selection, installation, maintenance, and in-service 

evaluations of crashworthy roadside safety hardware on their roadways, specifically: 

1. Relative to installation and maintenance of crashworthy roadside safety hardware, 

it is strongly recommended that they put in place the necessary protocols to ensure 

that any entity installing or maintaining roadside safety hardware, including 

contractors or State or local personnel, are capable (e.g., trained, credentialed or 

authorized by the roadside hardware manufacturer for the installation and 

maintenance oftheir hardware) of doing this work. 

2. Review standard plans and specifications to ensure that only crashworthy devices 

are used on the National Highway System (NHS). 

Finally, strongly encourage the highway agencies to increase their efforts to 

systematically upgrade pre-NCHRP 350 guardrail end terminals, particularly those that 

are on the NHS. 

Resources 

FHWA's Office of Safety and the Safety and Design Team in FHWA's Resource Center 

can provide training and technical assistance that focus on the proper selection, 

installation, and maintenance of guardrail end terminals to State Departments of 

Transportation (DOTs). Many states have taken advantage of this resource. 
3

FHWA’s Office of Safety will offer assistance to help set up pooled fund arrangements to conduct inservice performance evaluations.

For more information, accessing the above resources, or if you have questions or comments, please 

contact Will Longstreet at (202)366-0087 or Nick Artimovich at (202)366-1331.

References

• The September 29, 1994, FHWA memorandum, “Traffic Barrier Safety Policy and Guidance”, called 

for replacement of “blunt ends” and discontinued the use of turned down ends and Breakaway Cable 

Terminals. The memorandum also suggested a policy to upgrade these terminals.

• The August 18, 1998, FHWA memorandum, “National Cooperative Highway Research Program

(NCHRP) Report 350 Hardware Compliance Dates,” announced the FHWA-AASHTO Implementation 

Plan for NCHRP Report 350 hardware. This plan required the upgrade of terminals not meeting 

NCHRP Report 350 as part of 3R projects on the NHS.

• The October 26, 2004, FHWA memorandum, “Guidelines for the Selection of W-Beam Barrier

Terminals” identified several characteristics of W-beam terminals that need to be understood in order to 

select the appropriate system including site grading, type of terminal, and terminal layout.

• The November 17, 2005, FHWA memorandum, “In-service Performance Evaluation and Continuous

Monitoring of Roadside Safety Features,” identified the need to routinely conduct in-service 

performance evaluations of crash tested roadside safety hardware.

• The June 26, 2012, FHWA memorandum, “AASHTO Roadside Design Guide 4th Edition,” 

encourages State DOTs to have a written roadside policy that aligns with the AASHTO Roadside 

Design Guide, 4th edition.

Attachment

• Technical brief titled “Selection, Installation, and Maintenance of W-Beam Guardrail End Terminals.
This brief provides general guidelines regarding the selection, installation, and maintenance ofW-beam

guardrail terminals. In addition, common issues of concern are identified for these elemen ts with 

gene rally accepted practices to address these issues. The American Association of State Highway a nd 

Transportation Officials (AASHTO) Roadside Design Guide 4th Edition Chapter 8.3 provides additional 

guidance on terminal design concepts. 

Te rmina l Selection: 

There a re three primary W-beam guardrail end terminal designs in use at present: buried-inbackslope, non-energy-absorbing, and energy-absorbing. Figure 1 shows the relative trajectories of a 

vehicle impacting non-energy-absorbing and energy-absorbing terminals head-on and at high speed 

(62 mph). The decision to use either an energy-absorbing terminal or a non-energy-absorbing 

lerminal should be based on the likelihood of a near end-on impact and the nature of the recovery 

area immediately behind a nd beyond the terminal. 

[ITJ:J l:([f;J IMPACT 

FINAL POSITION 

I 

-riDJ 

OF VEHICLE I I . . I I I I I I I 

I:IDJ I I I I 

~· Non Energy-Absorbing Terminal 

FINAL POSITION 

OF VEHICLE IMPACT 

t' • • • . . I 

I~ A<ol ·E[U] 

Energy-Absorbing Terminal 

Figure 1: Vehicle Trajectories by Terminal Type 

US. Deportment of Transportation 

Federal Highway Administration 

e Roads for a Safer future ~ l•otrlmrnl lo l o•I"•V llftlg 11•rsll•u 

hllp://safety. fhwo.dol.gov 
Characteristics of the Different Terminal Types: 

I. Non Energy-absorbing- A terminal that does not dissipate a significant amount of kinetic energy in a head-on 

crash and is a gating system that allows the vehicle to traverse the area behind and parallel to the guardrail. 

Some key characteristics include: 

• Does not significan tly reduce vehicle speed in a near head-on hit 

• Run out distance can exceed 150 feet 

• Best specified when t here is a long, clear, traversable area behind and parallel to the guard rail installation, 

such as often found in a flat freeway median 

II. Energy-absorbing - A terminal that d issipates a significant amou nt of kinetic energy in a head on crash. Some 

key characteristics include: 

• Barrier installations less than 150 feet in advance of any shielded object must be energy absorbing 

• Energy-absorbing terminals have been shown to stop an impacting pick-up truck in about 50 feet when 

struck head-on 

• Best suited to locations where traversable area behind barrier is li mited; or, conta ins fixed object hazards. 

Il l. Buried-in-Backslope- A terminal that terminates a W-beam gua rdrail installation by burying the end in the 

backslope. Grading is critical for a buried-in-backslope terminal because the terrain leading up to the buriedin-bacl<slope must be traversable and contain no fixed object hazards. If the backs lope is relatively flat, a 

vehicle can ride up the slope and bypass the terminal. When th is condition exists at a site, the designer must 

ensure that the hazard remai ns shielded by assessing the available clear run out distance behind the rail and 

the barrier length-of-need. Also, there are other "grading'' design considerations to follow: 

• The backslope itself must be sufficiently steep to prevent a vehicle from climbing over the rail 

• The barrier fla re rate must be appropriate for the roadway design speed and traffic volume 

• The height of the rail must remain constant in relation to the roadway edge at least until the guardrail 

crosses the ditch flow-li ne 

• W-bearn rub ra il must be added if t he distance from the bottom of the primary rail and the ground exceeds 

about 17 inches. 

Figure 2 is a suggested flowchart that can be used by a designer to select the most appropriate terminal for a 

specific location. It's important to note that the starting point is to veri fy that a barrier is actually needed. If so, 

t hen the correct length of need shou ld be confirmed. If a total length of ba rri er is less than about 150 feet, an 

energy-absorbing terminal should be selected for the reason previously stated. When an appropriate 

backslope exists near the end of the barrier. the buried-in-backslope terminal should be considered. When no 

suitable backslope exists, either a non-energy-absorbing or energy-absorbing may be appropriate. 

O

I I Is Barrier No Discuss Elimination 

Needed? f Hazard with Engineer 

I 

Figure 2: 

I Is Length of No Adjust l ength 

G

Barrier Optimal? of Barrier 

e Buri;;j Yes l 

Terminal Backslope l is there a Steep Back51opo near 

,lby? ;11 crminal 

Selection 

Flowchart r------ Can Barrier s~be ~ r--Is Runout 

oL-----, Can ba rrie r be Area 

Te rminated in ~ Terminal ~ extended to obtain beyond 

Bukslope? adequate runout area? Adequate? 

~c ony - Yes Use Energy 

Cr11 shworthy Absorbing 

Terminal Terminal 
Terminal Selection: Common Issues of Concern and Current Ge nerally Accepted Practices. 

Common Issue of Concern Current General I ted Practice 

Side-by-side Terminals: 

If the ends of two barriers

are within seven fee t of 

each other, they should 

be combined and 

terminated as a medi an 

ba rrier or a bullnose 

design should be 

considered. This should 

Bullnose Guardrail 

System for Median 

Appli cations 

reduce the potential for 

the vehicle to reach the 

haza rd or obstruction. 

Common Issue of Concern 

.c.u.ms 

The presence of a curb 

can introduce instability 

as the vehicle hits the Refer to NCHRP ReP.Ort 537 

terminal and should be Recommended Guidelines 

avoided or minimized if Curb-Guardrail 

possible. In addition, Combinations added rub rails or other 

for Curb and Curb- Barri er 

Installations. There are 

tested curb and guardrail 

items not part of the and curb and end terminal 

original design might combinations covered. 

affect the performance of

the te rminal and should 

not be added. 

Common Issue of Concern 

In adequate Length of Extending the barri er or a buried-in-backslope to 

Need (LON). appropriately shield the hazard. 

Guardrail insufficient length 

to shi eld the hazard. 

Common Issue of Concern 

Terminal flare rate can be A gating terminal may be considered here 

excessive on a flared terminal. because of existing run out area. 
Figure 3: Terminal Grading Areas 

f

The "grading platform" in the 

photo has a drop-off that 

creates a significantly greater 

hazard than previously existed. 

Common Issue of Concern 

Advance Area: 

The "advance area" consists of the 

space traversed by an errant 

motorist before the terminal is 

struck. If a terminal "platform" is 

constructed, it must be smoothly 

blended into the existing roadside 

embankment so a motorist has an 

opportunity to return to the 

roadway without striking the 

terminal or losing control of the 

vehicle by dropping off the edge of 

a steep platform before impact. 

Before selecting a grading platform, the 

designer should first consider the 

o ll owing: 

a. extending the barrier a short 

distance to a flatter location. 

b. specifying a non-flared end 

treatment. 

Terminal Insta llation: 

When installing the terminal, the manufacturer's installation manual s hould be followed closely. Additionally, 

grading in the area of the terminal is important because terminals are tested for crashworthiness on flat and 

unobstructed terrain. /\s shown in Figure 3, there are three grading locations of concern around barrier terminals: 

a. Advance area 

b. Adjacent area 

c. Run-out area 

All of these areas should be carefully conside red during the design phase ora project. Engi neered earthwork and 

specification of a platform* should also be considered to achi eve successful termina l performance. In addition, 

necessary earthwork should be completed prior to the installation of the safety feature. 

*A platform is the required grading for both adjacent & advance areas to acceptable criteria per the Roadside 

Design Guide. 

Terminal Installation: Common Issues of Concern and Current Generally Accepted Practice 
Terminal Installation: Common Issues of Concern and Cu rrent Generally Accepted Practice (Continued) 

Ad jacent Area: ~-_... A field check should be made to determine 

When t he area immediately behind if a run-out area exists. A run-out area 

a terminal (i.e., the "adjacent area")~~~ requires the following: 

is steep or non-traversable, a a. Minimum traversable area of20-feet 

vehicle can overturn after breaking wide & 75-fect long. This distance is 

through the terminal. A minimum based on the final resting position 

traversable area behind the typically found for a small car during 

terminal is an essential part of crash testing. 

good barrier design. b. A heavi er vehicle at a higher speed 

will typically travel a greater distance 

behind and beyond the terminal. 

Common Issue of Concern 

Ad jacent Area: In many situations, it simply may not be 

Although the terminal shown here practical to shield every hazard. This 

is an ene rgy-absorbing design, any barrier was installed primarily to shield 

impact into the end will most likely the slope along the curve and is effective 

end with a vehicle striking the for that purpose, but it should have been 

utility pol e. lengthened if practical. to shield the 1m 

also. An energy-absorbing termina l can 

slow a vehicle in line with the rail and is 

preferable here rather than a non-energyabsorbi ng design. 

Advance & Adjacent Area: To achieve successful terminal 

The adjacent grading is the area performance, the designer should 

around the 1st post and is critical to consider including engineered earthwork 

help develop the anchor strength as a key component on the final 

and ensure that the post stubs and construction plan for the terminal 

strut do not stick out more than 4" ~ji!iii-~ installatio n. 

above the ground. The terminal in 

the photo is neither crashworthy 

nor a good anchor. When a ground .__ ___ _..;;:-. ........... ~--- """"""__.1 

strut anchor is used, it is normally 

at 'ground level'. 

The installation shown here is an The guardrail should have been extended 

energy-absorbing design, so a to shield the secondary hazard (i.e .. the 

vehicle impacting head-on would rocl< wa ll). A good fie ld check to determin 

likely be stopped safely before i! ::il if shieldi ng secondary hazards may be 

reaching the concrete barrie r. >o--c..or:-.... worthwhile is to note whether or not the 

However, any angled hits at the area immediately upstream from the 

end would result in significant 

intrusion behind the rail and into 

terminal would warrant shielding in the 

------i absence of a primary hazard (i.e., end of 

the rock outcropping. the bridge barrier). 
Terminal Maintenance: 

The Roadside Design Guide identifi es maintenance factors grouped into three categori es: (1) routine maintena nce, 

(2) Crash Maintena nce, and (3) material and storage requ irements. Common exampl es of routine maintenance and 

material and storage requirements are listed below. Routine maintenance includes inspecting roadside devices at 

regu lar intervals to determine the condition of the device and required repair need ed for the device. Proper 

materials and storage of t hem ensures routine maintenance is carried out appropriately using proper components 

when completing repairs. 

Extruder Heads 

Routine Maintenance: Care is needed when installing and 

repairing extruder head type te rminals to ensure that the head i

properly attached to the rail. This photo shows a case where the

terminal of the head is not properly attached to the rail and will,

therefore, not perform properly, and should be repa ired 

immediately. This situation can also occur if the barrier is 

impacted upstream with sufficient force and d efl ecti on that the 

rail pulls out of the head. 

s 

Cable attachments 

Routine Ma intenance: The cable is criti cal in providing tensile 

strength in the rail. r:or some designs, the cable must be able to 

detach from the rail during an impact. The photo shows a location

where the cable is not attached and where the bolts holding the 

cable were installed backwards. 

Cable anchorage 

Routine Maintenance: The photo s hows a locati on where the 

s houlder bolts holding the cable were installed backwards and a 

metalli c butterfly refl ector was placed within the end treatment 

performance area, which may adversely affect the separation of 

rail from the post Attachments to the guardrail within this 

performance area should not be made. 

Mismatched Pa rts 

Material and Storage Requirements: The photo shows an inservice insta llation using components from two diffe rent 

syst ems. This is likely due to imprope r maintenance 

decisions being made after an impact. Parts from one 

system to another system are not interchangeable unless 

specifi ed by the manufacturer. 
In efforts to effectively address the highlighted concerns, the following existing resources and noteworthy 

practices are provided for consideration by State Departments of Transportation and other highway 

agencies. 

• Inspector /Maintenance & Designer Mentoring Training 

State and local agencies should conduct training at regular intervals for DOT personnel, consultants, 

and contractors to ensure the optimal barrier design and installation of new roadside safety devices, 

and the inspection and maintenance of existing devices. This noteworthy practice would serve to 

eliminate common installation and maintenance errors that adversely affect the intended 

performance of the roadside safety device. 

• Installer Certification 

Installer Certification is training for the roadside safety system installers that may be offered at 

regular intervals to maintain a specific knowledge base of both existing and new systems. Agencies 

that offer this training may also make this a requirement for installation of roadside safety systems in 

their jurisdiction. This noteworthy practice also may serve to eliminate common installation errors 

that may adversely affect the intended performance of the roadside safety device. 

• Engineered earthwork design in construction plans 

Crash testing for end treatments is performed on flat or near flat terrain. In real world applications, 

this type of terrain is fairly rare and some grading is likely needed. Therefore, end treatments may 

require individual construction details and cross sections with regard to earthwork analysis. If this 

information is not included in the plan, the end treatment may not fit or function as intended when 

installed in the field. In some cases, improperly installed end treatments can degrade the strength or 

performance of an entire barrier system. 

• Use of Roadside Safety Systems Pre-Installation Field Review Checklist 

When roadside safety systems such as traffic barriers and terminals are installed exactly as 

shown on project plans or replaced in-kind after a crash, the end result can be an installation 

that may not effectively shield the primary hazard, may be too short or too long, may not shield 

obvious "secondary" hazards in its immediate vicinity, or may not be needed at all. A pre-installation 

review checklist can be used to recognize field adjustments to a design that are needed to ensure an 

optimal installation.