US.Deportme-1t 

of lrcnsportotioo 

Federal Highway 

Administration 

Subj ect: ACTION: E- Plus W- am 

From: Tony Furst 

Associate A 

I 

To: Division Admimstrators 

Director of Field Services 

Memorandum 

Date: OCT I 0 LIJ ~~ 

fn Reply Refer To: 

HSA 

In June 20 14, in response to several inquiries from State Departments ofTransportation, 

the Federal Highway Administration's Office of Safety issued a memorandum regarding 

the Federal-aid eligibility of the ET-Pius w-beam guardrail end terminal manufactured by 

Trinity Highway Products (Trinity). This memorandum updates the 20 14 memorandum 

to advise you about several recent developments. 

Background 

In general, FHWA's eligibility letters confmn that roadside safety hardware was crash 

tested to the relevant criteria, that those crash test results were presented to FHW A, and 

that FHW A confirmed that the device met the relevant crash test criteria. 

Each Highway Agency must make its own determination regarding the installation and 

continued use of any roadside safety hardware based on fie ld conditions and may place 

limits on use based on its interpretation oftest results, additional testing, in-service 

evaluations, or other reasons. Highway Agency detenninations regarding the installation 

of roadside safety hardware and conduct of in-service perfom1ance evaluations are 

addressed in the two attached memoranda from FHWA's Office of Safety. 

Recent Developments 

The Missouri and Massachusetts Departments of Transportation suspended the ET-Pius 

from their qualified products lists pending further examination of the field performance of 

these end terminals. These suspensions are local decisions and not the result of 

instructions from the FHW A. 

Ongoing Activity 

The FHW A is working with the American Association of State Highway and 

Transportation Officials and the Transportation Research Board to develop and conduct a 

comprehensive evaluation of diffe rent categories of roadside safety hardware end 

treatments through the National Cooperative Highway Resea rch Program. 
2 

Action and Request for Information 

FHWA requests information from State DOTs regarding the performance of the ET-Plus 

in the field. Please immediately contact your State DOTs and advise them of these recent 

developments, ask that they pay particular attention to all crashes involving these devices, 

and request that any findings from their investigations be shared with the FHW A Office of 

Safety. As more information becomes available, it will be shared with you and with all 

States. 

Attachments 
Memorandum - FHW A Safety Program Page 1 of 1 

Memorandum 

US Department of Transportation 

Federal Highway Administration 

Subject: INFORMATION: In-service Performance Evaluation and Continuous Monitoring of Roadside Safety Features 

Date: November 17,2005 

From:John R. Baxter, P.E. 

Director, Office of Safety Design 

In Reply Refer To: HSA-10 

To: Safety Field 

Ideally, all highway agencies should know precisely what has been incorporated into its roadway/roadside infrastructure and be 

able to monitor the performance of individual components of its highway system. Asset management has become a primary 

means of accomplishing this goal in many states. However, there remains one area where in-service evaluation or 

performance monitoring seems to be minimal at best, and that is the area of roadside safety features. 

As some of you may recall, when the FHWA began formal acknowledgement of successfully crash tested safety 

appurtenances in the late 1980's, we first accepted a device as an experimental feature, and later upgraded it to operational 

status when enough crash data had been gathered to show that it was, in fact, performing as desired under varied field 

conditions. Several State transportation agencies were reluctant, however, to install a safety device that was labeled 

experimental and many believed the evaluation process itself to be both time-consuming and expensive, so our two-phase 

acceptance procedure was dropped. Unfortunately, formal in-service evaluations of safety devices were dropped as well by 

most States. 

Because the crash tests by which safety features are deemed acceptable for use on the NHS are conducted under ideal 

conditions, are limited in number, and use only two vehicle types, this testing may not reveal longer term operational, 

maintenance, or repair problems that do not become apparent under short-term certification testing. Actual field experience 

must be monitored to assure that a safety device is working as intended. In fact, Chapter 7 of the NCHRP Report 350 outlines 

a simplified procedure for conducting in-service performance evaluations on devices deemed crashworthy through standard 

testing procedures. The NCHRP Report 490, "In-Service Performance ofTraffic Barriers", published in 2003, summarized the 

results of field evaluations of barrier terminals conducted in three states and provided a model methodology that can be used 

by hardware manufacturers and transportation agencies to monitor the performance of their hardware. 

Several States routinely conduct in-depth evaluations at locations where fatal or otherwise severe crashes have occurred in 

order to assess potential liability firsthand, but also to determine if roadway or roadside design contributed in any way to the 

severity of the crash. This specific activity should be conducted by those in the highway agency who are responsible for the 

design and maintenance of the roadside safety hardware and may be reported as part of each State's HSIP as it will provide 

valuable input into the report required under 23 U.S.C. 148 (g). 

I am enclosing an evaluation study recently completed by a manufacturer on a unique crash cushion that had been developed, 

tested, and accepted for use on the NHS. In this case, our formal acceptance letter (CC-85) requested that an evaluation be 

conducted since the product was different from others on the market. One can readily see that the report is very 

straightforward, primarily requiring notification when a crash occurs and follow-up on site to obtain as much information on the 

consequences of the crash - to the vehicle involved, its occupants, and the device itself. 

Both types of assessments should be an ongoing effort at all levels and for all roadside safety features to verify expected 

impact performance and, as suggested above, can be used as input to assess the effectiveness of the roadway departure 

elements of each State's overall HSIP. 

Attachment 

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Memorandum - FHWA Safety Program Page 1 of8 

Memorandum 

US Department of Transportation 

Federal Highway Administration 

Subject: ACTION: Application and Installation of Roadside Hardware (REVISED November 3, 2010) 

Date: November 3, 2010 

From: MichaelS. Griffith 

Director, Office of Safety Technologies 

In Reply Refer To: HSSI 

To: Division Administrators 

Summarv of Action Required 

This memorandum addresses the proper application and installation of roadside safety hardware, and supersedes 

the memorandum of the same subject dated October 1, 2010. Each Division Office should ensure that its State 

highway agency includes safety hardware design, selection, construction, and maintenance in their oversight reviews 

of projects on the National Highway System (NHS). 

Background 

While many devices have been developed to improve roadside safety, it is imperative that their effectiveness be 

maintained through proper application and installation. In other words, we must assure that the correct device is 

used for a particular situation, and that it is installed correctly. 

It is the responsibility of the owner agency to verify proper hardware selection and installation for the intended use. 

Misapplication of safety hardware can result from misinterpretation of details of the crash tested hardware in the 

design, construction, and maintenance phases. As a service to the roadside safety community, the FHWA has been 

writing formal Acceptance Letters for roadside hardware since 1976. Letters are issued for devices that have been 

successfully crash tested, or have been evaluated by FHWA and judged to be equivalent to crash tested devices 

because of their similarity to the original device. These letters acknowledge that the devices meet the requirements 

of NCHRP Report 350 or the AASHTO Manual for Assessing Safety Hardware (MASH) and often include detailed 

information on proper installation or cautions on improper usage. 

For example, our acceptance letter for a crash cushion included the following: 

"Non-redirective, gating systems are designed to allow penetration into the area behind the system 

when struck at an angle on the side by an errant motorist. Furthermore, as seen in [the crash testing] 

some high-angle, high-speed impacts into the side of the ... attenuator can result in vehicular vaulting 

and subsequent intrusion over 100 feet into the area behind the barrier, thus requiring a significant 

clear runout area. This fact must continue to be stressed in your product literature and to your 

customers to ensure proper barrier design and layouts in the field.· 

Each Division Office should ensure that its State highway agency includes safety hardware design, selection, 

construction, and maintenance in their oversight reviews of projects on the NHS. State personnel should be made 

aware of the resources available on the FHWA Safety Web site where details of each federally-accepted roadside 

safety device are linked: http://safety.fhwa.dot.qoy/roadway dept/policy guide/road hardware. 

Attachment A consists of frequently asked questions regarding the proper installation of accepted roadside safety 

hardware and its intended use. Attachment B consists of errata to the AASHTO MASH courtesy of the Midwest 

Roadside Safety Facility. 

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Memorandum - FHW A Safety Program 

2 Attachments 

cc: Mr. John R. Baxter, Associate Administrator for Federal Lands 

Mr. King W. Gee, Associate Administrator for Infrastructure 

Mr. Jeffrey A Lindley, Associate Administrator for Operations 

Federal Land Engineers 

Mr. Pat Hasson, RC Safety and Design Technical Service Team 

Mr. Rob Elliott, RC Construction and Project Management Technical Service 

Mr. Grant Zammit, RC Operations Technical Service Team 

Mr. Shay Burrows, RC Structures Technical Service Team 

Safetyfield 

More Frequently Asked Questions 

(The first series of frequently asked questions (FAQs) are on line at: 

http://safetv.fhwa.dot.gov/roadway dept/policy guide/road hardware/ga bttabr.cfm) 

Page 2 of8 

Attachment A 

The FHWA barrier guidance is contained in the AASHTO Roadside Design Guide. However, FHWA field offices 

raise numerous issues that involve interpretations, extrapolations, device selection, hardware deployment, or simply 

trying to fit safety devices into real world conditions. These questions and answers offer clarification on the use of 

roadside hardware for issues not covered by FHWA policy or topics that simply need additional explanation. These 

answers represent the professional opinions of engineers in the FHWA Office of Safety. Please refer to these FAQs 

before contacting FHWA Headquarters or Resource Center experts. 

The Division Office is in the best position to know if any of these concerns apply in its State. Please discuss them 

with your State and express our mutual interest in seeing that roadside safety hardware is selected, designed, 

installed, and maintained in a manner that will achieve the greatest probability of saving lives. 

CRASH CUSHIONS 

Q: WHEN CAN I USE A NON-REDIRECTIVE CRASH CUSHION? 

A: Care must be used in applying a non-redirecting, gating crash cushion. They are designed to decelerate a vehicle 

impacting head-on on the nose. Vehicle penetration is likely to occur for angle hits from the nose to near the midpoint of the array. Vehicle penetration I override of the system is possible for high speed, high angle impacts near the 

rear of the device. 

All gating, non-redirective crash cushions should be applied to hazards that are not likely to be impacted at an angle 

on the side at any significant velocity. They are appropriate on low speed facilities, and in work zones with higher 

speeds where lane widths are constrained and the potential for high angle hits is limited. Potential problems with 

these non-redirecting attenuators include vaulting over the nose of the attenuator into the work area, and inadequate 

clear run out areas behind the devices. Side redirect impacts into these devices are known to push acceptable safety 

limits and as such, their use in the field requires scrutiny to ensure adequate safety for both vehicle occupants as 

well as workers in downstream construction areas. Typical examples of non-redirecting/gating attenuators installed in 

a manner that increases the likelihood of compromised impact performance include: 1) not providing adequate clear 

run-out areas behind these units and 2) positioning them at sites where the probability of high-speed, severe-angle 

(i.e. - high energy) impacts is high. 

All users of these devices should be made aware of the factors that contribute to proper performance as outlined in 

the crash test report. Examples of 

non-redirecting, gating crash cushions include all sand barrel arrays, the Triton CET (Concrete End Treatment), 

ACZ350, NEAT, and the ABSORB 350. 

Please note that adequate clear run out areas are required for both non-redirective and redirective devices. The run 

out areas are longer for non-redirective devices. The additional length is typically the length of the non-redirective 

device. 

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It should also be noted that non-redirective crash cushions such as sand barrel arrays can pose a hazard if impacted 

in the reverse direction on the heavy barrels adjacent to the rigid hazard. Impact in the reverse direction at this point 

in the array is untested and the large mass of the final barrels could cause rapid and violent deceleration of the 

impacting vehicle that would exceed our occupant risk limits. 

Q: WHAT TYPE OF CRASH CUSHION SHOULD I USE? 

A: When more than one crash cushion I impact attenuator system is approved for use in your State, carefully 

evaluate the structural and safety characteristics of each candidate system for the site in question. These include 

such factors as impact decelerations (as indicated by the Test Level to which the device was tested), redirection 

capabilities, anchorage and back-up structure requirements, and debris produced by impact. All of the systems 

described in the Roadside Design Guide as meeting MASH or NCHRP Report 350, TL-3 evaluation criteria have the 

capability to stop compact cars and pickup trucks impacting head-on at 1 00 km/h [62 mph) within tolerable 

deceleration levels, and to redirect or contain those vehicles impacting on the sides of the units within the system's 

length-of-need. However, the costs of initial installation and maintenance, the ease of repair, and the system's 

durability (to environmental conditions and impacts) vary greatly. In addition, the contract plans need to include 

enough details showing the type of system desired, the hazard needing protection, and/or how the specifying agency 

intends to have the device attached to the hazard. 

Attenuators that are categorized as self-restoring or low maintenance are premium systems that are designed for 

high traffic areas where impacts can be expected to be frequent. The high initial cost can be offset by the long-term 

savings in maintenance and repair costs. 

Traffic speeds, geometric constraints, weaving maneuvers, congestion, worker exposure, space available to repair, 

potential for secondary impacts, and sight distance are just a few of the factors that should be considered at potential 

locations for redirective crash cushions. They have demonstrated the ability to redirect vehicles away from the corner 

of the hazard, as well as safely decelerate vehicles hitting the nose of the attenuator head-on. 

Sand barrel arrays are most appropriate for hazards that are located well off of the traveled way where impacts are 

expected to be infrequent, yet very serious when they do occur. The relatively low initial cost of these sacrificial crash 

cushions is a good investment to prevent serious injury when a crash does occur. 

W-BEAM GUARDRAIL 

Q: WHERE DO I MEASURE THE HEIGHT OF THE GUARDRAIL FROM? 

A: There are a number of different scenarios for guardrail height measurement. Only the first one is easy: 

1) Guardrail is located above pavement: Measure the height from the pavement to the top of thew-beam rail. 

2) Guardrail is located 2 feet off of the edge of the pavement: Use a 1 0-foot straightedge to extend the 

pavement/shoulder slope to the back of the rail. Measure from the bottom of the straightedge to the top of the rail. 

3) Guardrail is located 2 feet off a recent pavement overlay: Follow the guidance in #2 above. You may have to reset the barrier to achieve proper height. The gap between the pavement edge and the guardrail posts should be 

backed up with fill material to accommodate low-speed or shallow angle incursions. 

4) Guardrail is located down a 1V:10H slope: Measure from the nominal terrain. Good contractors can get fairly even 

grading, but it will rarely be perfect enough to always be spot on the design height. Use a string line or straight edge 

to even out terrain variations. 

5) Guardrail is located down a 1V:4H slope: If located more than 2 feet beyond the slope break point, remove the 

guardrail. Guardrail may not be placed on a steep slope. The Roadside Design Guide specifies where you may place 

guardrail on slopes as steep as 1 V:6H, but guardrail must remain about two feet off the edge of the shoulder when 

there is a 1 :4 slope behind it. (If steeper than 1 :3 you may need longer posts, or additional posts, but that is yet 

another forthcoming FAQ pending the completion of ongoing research.) 

Q: WHY IS THE W-BEAM CONSTRUCTION TOLERANCE NOW ONLY ONE INCH? 

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A: Crash testing has shown that the standard strong post w-beam guardrail without rub rail is acceptable in the range 

from 27-3/4 inches to 30 inches above the ground. When the rail was tested at a lower height the pickup truck 

vaulted over the rail. A taller rail without rub rail can cause significant wheel snagging on small cars. This leaves a 

very narrow range of installation heights, and FHWA recommended 29 inches +/- one inch. 

The Midwest Guardrail System (MGS} tolerance is greater at plus one to minus three inches. The MGS was initially 

tested at its design height of 31 inches with 12-inch blackout with no rub rail. It was known that the performance 

would be acceptable down to 27-3/4 inch just like the G4(1S} but we wanted to encourage the taller initial height so 

we recommended a construction tolerance of just one inch from the design height of 31 inches. A subsequent crash 

test (in July 2010} of the MGS at a height of 34 inches using the small passenger car was successful (which is 

generally considered the worst case scenario for tall guardrail}, and now testing with the MASH pickup truck at 34 

inches (or above} is pending to confirm an installation tolerance of+/- 3 inches. 

Q: HOW DO WE HANDLE THE HEIGHT TRANSITION BETWEEN G4(1S) AND MGS AND THEIR TERMINALS? 

A: You should transition from a 27-3/4 inch tall barrier or terminal to a 31-inch tall barrier over the span of two 12-

foot, 6-inch pieces of w-beam rail. When replacing or repairing long portions of a damaged rail the new rail should be 

installed at the proper design height, transitioning down to the existing rail over the length of two 12 foot, six inch, 

pieces of rail at either end. W-Beam to Thrie-Beam bridge transitions may need to use the non-symmetric W-to-Thrie 

connector that keeps the top height of the entire rail at approximately 31 inches. In addition, there is no need to 

transition in height to many 27 %-inch high terminals. The SKT, FLEAT, and ET end terminals have all been tested 

and accepted at the 31-inch rail height and provide the benefits of 31" guardrail without transitioning in height down 

to a lower system 

Q: OUR GUARDRAIL CROSSES A CULVERT AND WE CAN'T DRIVE A POST. CAN WE OMIT THE POST? 

A: The Midwest Guardrail System (31-inch rail height} has been successfully tested with three posts omitted, leaving 

a span of 25 feet. Special posts (CRT, or Controlled Releasing Terminal posts} are used at either end of the gap but 

the rail does not have to be doubled up, or unested" over the gap. Standard strong-post w-beam rail (minimum 27-3/4 

inch rail height) can also be installed with three CRT posts at either side of a three- post gap, but the rail needs to be 

nested across the gap as well as up- and down-stream from the gap, for a total length of 100 feet. In addition, the 

MGS system is allowed to be placed closer to the headwall than the nested W-beam long span system. 

Q: CAN WE PAVE A MOW STRIP UNDER OUR GUARDRAIL? 

Q: CAN WE PLACE GUARDRAIL POSTS IN A CONCRETE SIDEWALK OR MEDIAN? 

A: Concrete or asphalt pavement under the guardrail would have to be constructed with a gap behind the post and 

backfilled with a loose material to allow the post to move when the rail is struck. An asphalt spray surface treatment 

would be acceptable as it would not prevent post movement through the soil. There are also various commercial 

products that can be placed under the W-beam to block weeds. Check with the manufacturer to see that they have 

designed the product with post deflection in mind. The FHWA also provided guidance on this issue in 2004 in our 

memorandum "W-Beam Guardrail Installations in Rock and in Mowing strips," 

http://safety.fhwa.dot.gov/roadway dept/policy guide/road hardware/barriers/pdf/b64b.pdf 

Q: HOW CAN WE DESIGN OUR BARRIERS TO BE "MOTORCYCLE-FRIENDLY?" 

A: Any time a motorcyclist leaves the roadway unintentionally there are likely to be severe consequences. Even the 

"safest" barriers can cause serious injury whether the motorcyclist is still on his/her bike or they are sliding/rolling on 

the pavement. Although there are many barrier modifications being used in Europe intended to moderate the 

severity of impact with guardrail posts, FHWA does not yet advocate the use of any such modifications on the NHS. 

As of Fall, 2010, there are two research projects underway that will analyze motorcycle crashes in depth. One is a 

general study of motorcycle crash causes, while the other is specifically targeting motorcycle impacts with roadside 

barriers. When these studies are completed, we hope to have information that will help us to determine the nature of 

motorcycle impacts with barriers, and whether or not the barriers can be redesigned without adversely affecting the 

good performance we have experienced with four-wheel passenger vehicle impacts to date. 

Q: MANY OF OUR GUARDRAIL TERMINALS HAVE A STEEL BEARING PLATE ON THE FIRST POST THAT 

SOMETIMES ROTATES UNTIL IT IS UPSIDE-DOWN. IS THIS OK? 

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A: No. This bearing plate (8 x 8-inch square with an off-center hole) must be installed with the longer dimension 

upright (5" dimension up and the 3" dimension down). If the cable slackens over time traffic vibrations may allow this 

plate to rotate downward due to gravity. If this happens the ability of post #1 to fracture in a head-on impact (thus 

preventing a snag point) is severely compromised. On wood posts, a nail can be driven to prevent this rotation. A 

solution that works on both wood and steel breakaway posts is to specify that this steel plate be fabricated with tabs 

on either side that will wrap around the side of the post an inch or so to prevent rotation. This is an acceptable 

modification to all crashworthy terminals that use this 8 x 8-inch bearing plate. Of course, it is still critical to install the 

bearing plate with the 5" dimension up and the 3" dimension down. (The function of the bearing plate is to transfer 

load from the cable to the end anchorage.) 

Q: HOW DO WE KNOW THAT DAMAGED BARRIER NEEDS REPAIR? 

A: Small dents and dings do not seriously affect the performance of guardrail. Vertical tears and bent posts are a 

different matter. A recent NCHRP study was completed and published as "Criteria for Restoration of Longitudinal 

Barriers" and it is available for download at hUp://onlinepubs,trb.org/onlinepubs/nchrp/nchro rpt 656.pdf. 

Also, the 2008 FHWA guide "W-Beam Guardrail Repair" is available for download at: 

http://safety. fhwa. dot. goy/local ru ra lltraining/fhwasa08002. 

Q: WHAT GUARDRAIL HARDWARE MUST BE REPLACED OR UPGRADED ON THE NHS? 

A: On September 29, 1994, the FHWA Executive Director signed a memorandum "ACTION: Traffic Barrier Safety 

Policy and Guidance" that identified various items that were to be inventoried and scheduled for replacement or 

upgrade if found within the clear zone. The FHWA Headquarters did not conduct a formal follow up to that memo. 

But now, more than 

15 years later, it is time all remaining examples of these devices/situations be scheduled for correction as soon as 

practical. Terminals meeting NCHRP Report 350 or MASH are to be used. 

The following terminals/transitions should be upgraded on the NHS: 

1. Blunt End Terminals* for W-beam guardrail or median barrier. 

2. Turned-down terminals* 

3. Bridge approach guardrail that is not connected to the bridge railing. 

The following device is to be upgraded whenever encountered within the limits of a project on the NHS: 

4. Breakaway Cable Terminal ... 

We are currently preparing a memorandum dealing with upgrading of length-of-need guardrail and will address 

height of the barrier that may remain in place, offset blocks, rectangular washers, post length relative to the hinge 

point, and other details. 

*Versions of these terminals may be used on the downstream end to anchor the rail jf they are outside the reverse 

direction clear zone and/or cannot be struck by vehicles crossing the centerline or median, impacting from the 

opposite direction. 

**The BCT may also remain as a downstream anchor if outside the clear zone. It is also acceptable for use within 

some cable-to-guardrail transition designs. A crash test of the BCT as a Test Level 2 device failed. 

Q: WHAT KIND OF FOUNDATION DO WE NEED FOR OUR CONCRETE MEDIAN BARRIER? 

A: Many variations exist between highway agencies regarding reinforcing and footing details for concrete median 

barriers; however, there have been few reported problems with any particular design and a need for a standard 

detail is not apparent Concrete median barriers develop loads as a function of the barrier capacity and the 

foundation capacity. While it is true that some median barrier designs have been show to work with minimal 

foundation design, this does not suggest that any median barrier design can be installed in this manner. Thus, it falls 

on the designer to consider the combination of barrier and foundation that meets the design impact loading safely. 

Breakaway oevices 

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Q: SHOULD WE USE BREAKAWAY BASES FOR SIGN AND LIGHT POLES MOUNTED ON CONCRETE 

MEDIAN BARRIERS? 

A: No, breakaway bases should not be used. Mounting any pole on top of a median barrier should be avoided 

because trucks will lean over the barrier upon impact and hit whatever is on top. A rigid pole may or may not break 

off, but there is no safety advantage in making it easier for the pole to break away and fly into the opposing travel 

lanes. 

The potential for a pole being struck by the box of the truck can be minimized by making the barrier wider. If you 

transition to a vertical face and/or taper the width of the barrier you can provide additional offset to the pole. The 

point is to minimize the potential for broken poles to fly into the opposite roadway. Larger passenger vehicles as well 

as their occupants may contact objects on top of barriers under severe impact conditions. 

Work zone signs may be mounted on barriers if you use roll up signs on fiberglass supports as they have less 

potential for causing serious damage. 

Q: Can we still use pendulum tests to assess breakaway performance of sign and lighting poles? 

A: The status of pendulum testing under MASH is undetermined - if the bases can be considered modifications of 

bases tested under Report 350 then we will agree to review pendulum testing done under 350 criteria (until1/1/11). 

If they are totally new designs, then they need to be tested under MASH. Whatever test method you use must 

evaluate the roof crush and windshield damage as required in MASH. Based on experience in reviewing both full 

scale testing and pendulum tests of breakaway supports, we do not see how pendulum testing can answer those 

questions. The old "rule of thumbn limiting luminaire supports to 1 000 pounds cannot be relied upon because vehicle 

structures have changed and MASH now requires the pickup truck be used. Crash tests of luminaire supports with 

pickups is very limited (we are not aware of any such tests) so we have no way to assess the potential for roof crush 

except through full-scale testing. 

Q: Should we use omni-directional breakaway bases everywhere? 

A: Crashworthy omni-directional bases are designed to meet NCHRP Report 350 criteria regardless of which 

direction they are struck. They are required when installing signs and other breakaway hardware near intersections 

(including expressway ramps ending on local roads and in roundabouts) and preferred on other undivided facilities. 

Uni-directional bases (i.e., 4-bolt slip bases) should only be used along divided highways where impacts are limited 

to the direction of travel of the roadway they are next to. 

Q: SHOULD TREES, POLES, OR OTHER FIXED OBJECTS BE ALLOWED IN A ROUNDABOUT? 

A: Typically it is desirable to have some type of streetscapellandscaping installed within the central island of the 

roundabout to increase conspicuity, break the headlight glare of oncoming vehicles, and promote lower speeds 

through the roundabout. However, care is needed when 

considering landscaping that introduces fixed objects that may pose a safety concern for errant vehicles. In most 

cases, fixed objects should be minimized in the perimeter area of the central island where there is a higher risk of the 

objects being struck. 

Small trees, structures and statues placed within the inner portion of the central island may offer the benefit of 

helping obscure the line of sight straight through the roundabout. The perimeter portion of the central island may be 

landscaped with low-level vegetation so that stopping sight distances are maintained for vehicles within the 

circulatory roadway and at the entrance lines of the roundabout. 

As for "clear zone", consideration of the roundabout context and expected operating speeds should be considered 

consistent with the principles outlined in the updated AASHTO Roadside Design Guide for urban conditions. 

Q: WHAT IS THE JANUARY 1, 2013 DEADLINE FOR BREAKAWAY SUPPORTS? 

A: All sign supports within the clear zone of highways signed at speeds of 50 mph or greater must be mounted on 

breakaway supports or be shielded with a barrier by January 1, 2013, per the M UTCD. 

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Breakaway supports meeting the current crash test criteria* have been required on all Federal-Aid Projects since 

1990. (Since the ISTEA of 1991 that requirement has applied to all projects on the NHS regardless offunding 

source.) The 2000 edition of the MUTCD made breakaway supports mandatory for signs within the clear zone Q!..2!! 

roads open to public trayel in the United States. This requires that all new sign installations be on breakaway 

supports. While shielding with guardrail is an option, use of breakaway supports is preferred. The 2003 edition of the 

MUTCD set a 1 0-year implementation period to retrofit sign supports on highways signed at 

50 mph or greater. 

* The 'current crash test criteria' were established in 1985 with the publication of the AASHTO Standard 

Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals. The 1993 NCHRP Report 

350 incorporated the same test and evaluation criteria in metric form. Because the metric conversion in Report 350 

resulted in tests that were slightly more liberal than the 1985 Specifications, all breakaway testing done between 

1985 and 1993 is considered acceptable under NCHRP Report 350. The 2009 MASH adds the pass/fail criteria for 

windshield damage and roof crush, and requires testing with the 5000# pickup truck, but maintains test and velocity 

change evaluation criteria for the small car equivalent to that adopted in 1985. 

Q: WE WANT TO ADD LIGHTS, A BATTERY, AND A SOLAR PANEL TO OUR SCHOOL ZONE SIGN. DOES 

THE COMBINATION HAVE TO BE CRASH TESTED? 

A: There are four factors that determine the acceptability of breakaway supports: 

1. Stub height (Must be 4 inches or less. As this will not change with the addition of auxiliary hardware it will not 

be discussed further.) 

2. Vehicle velocity change I occupant impact forces. The addition of flashing lights and solar panels or other 

auxiliary equipment will not likely affect the change in velocity experienced by the vehicle or its occupants 

unless it becomes substantial compared to the mass of the pole. Additional hardware attached at or above the 

sign will raise the center of gravity of the system slightly but since it is away from the base the breakaway 

features will still perform as intended. The overall mass of the pole, sign, and auxiliary equipment should not 

exceed 600 pounds. 

3. Windshield penetration. Windshield damage was not a formal pass/fail criterion under the 1985 AASHTO Sign 

and Luminaire spec and we did not change this when we adopted Report 350 in 1994. However, windshield 

damage will be pass/fail evaluation criteria under the AASHTO MASH. If the auxiliary hardware is at or above 

the sign, the effect should be minimal. 

4. Roof crush. Roof crush up to 5 inches was permitted under NCHRP Report 350, but very few sign installations 

even approached that amount. (Luminaire poles weighing 1000# or more could easily fail this test.) The 

addition of more hardware could increase the risk under low speed impacts, but roof crush can be controlled 

by following the 600 pound weight limit mentioned above. Under MASH, roof crush will be limited to 3 inches 

maximum. 

Safe placement of these types of devices on the sign also depends on the structure of the sign, the sign height, the 

type of vehicle impacting the sign, and the breakaway nature of the sign support when it is impacted. The conditions 

outlined above assume the sign pole is rigid and that the pole itself will not deform upon impact. Also the breakaway 

feature must be a slip base, frangible coupling system, or a cast aluminum transformer base - "base bending or 

yielding" systems such as u-channel posts, perforated square steel tube posts, or composite posts require full scale 

crash testing. 

Attachment B 

MASH ERRATA 

(Courtesy of the Midwest Roadside Safety Facility) 

This document contains all of the known corrections to the MASH 2009. The corrections are noted below. This 

document will be further updated over time as more corrections are identified. 

Corrections 

1. Appendix B - In the publishing of the final document, Appendix B was published using one of the early drafts of 

the section rather than the final version. As such, there are several discrepancies between the final version of 

Appendix B and the version in the published MASH document. These discrepancies include: 

http://safety .tbwa.dot.gov/roadway _dept/policy _guide/road_hardware/policy _memo/me ... 10/10/2014 
Memorandum - FHW A Safety Program Page 8 of8 

1. The soil test post size was changed from W6x15 to W6x16. A W6x16 was used in the test program to 

produce similar flange width to the standard W6x9 post. The W6x16 post was also used in order to prevent 

yielding of the post during deflection through the soil, thus allowing the testing to isolate the soil response. 

2. Changed the size of the soil fill hole on the drawings from 24" diameter to 36" diameter. We used a 36" hole 

in the 22-14 program and would recommend that labs use a similar size hole for their testing, however, it is 

not required to do so. There is some concern that a 24" hole may be too small to develop consistent post 

loading through 15" of post deflection. 

3. Some English to metric unit conversions were incorrect and were fixed. 

4. Some of the graph legends and formatting were modified for clarity. 

5. The unconfined compressive strength test noted in section 85 was changed from AASHTO T 208 to ASTM 

D2166. 

6. The final version of Appendix B is located on the AFB20 server with this document. 

1. \\129.93.15.147\public\AFB20\MASH Errata and Clarifications\ 

2. Table 5-1 of MASH: 

1. Criteria H should include Test Designation No. 82 

2. Criteria I should include Test Designation Nos. 45, 54, 60, 61, 62, 70, 71, 72, and 82. 

3. Test Designation No. 44 should be removed from Criteria I 

4. Criteria N should include Test Designation Nos. 37 and 38 for gating terminals as well as Test Designation 

Nos.40,41,45,62, 72,82,90, 91 

3. Table 2-1 of MASH: 

1. Table 2-1 of MASH is currently labeled as gross static mass for the MASH test vehicles. However, gross 

static mass includes the mass of a surrogate occupant by definition, and this has caused some confusion. 

Table 2-1 should be labeled "Vehicle Test Inertial Mass Upper and Lower Limits" in order to alleviate any 

confusion. 

4. Table 4-1 of MASH 

1. Table 4-1 of MASH currently lists the recommended masses and tolerances for the 1500A vehicle. The test 

inertial mass for the 1500A vehicle is listed a 3300 ± 220 lb (1500 ± 100 kg) while the gross static mass is 

listed as 3300 ± 75 lb (1500 ± 35 kg). The tolerances listed are incorrect on the 1500A vehicle for the test 

inertial mass. The test inertial mass should read 3300 ± 75 lb (1500 ± 35 kg). 

If further corrections are identified, we will continue to notify all of you. We would also request that the users of 

MASH contact us with other issues or discrepancies that they identify, so we can correct them and notify the group 

http:/ /safety .fhwa.dot.gov/roadway _dept/policy _guide/road_ hardware/policy_ memo/me ... 10/10/2014