U.S.Department 1200 New Jersey Ave., SE 

· of Transportation Washington, D.C. 20590 

Federal Highway 


Administration October 3, 2016 


In Reply Refer To: 


HSST-1/CC-130 


Mr. Kaddo Kotlunann 


Road Systems, Inc. 


3616 Howard County Airport 


Big Spring, Texas 79720 


Dear Mr. Kothmann: 

This letter is in response to your July 29, 2016 request for the Federal Highway Administration 


(FHWA) to review a roadside safety device, hardware, or system for eligibility for 


reimbursement under the Federal-aid highway program. This FHWA Jetter of eligibility is 


assigned FHW A control number CC-130 and is valid until a subsequent letter is issued by 


FHW A that expressly references this device. 


Decision 

The following devices are eligible, with details provided in the form which is attached as an 


integral part of this letter: 


• 350 SKT Terminal with MASH SKT Impact Head 

Scope of this Letter 

To be found eligible for Federal-aid funding, new roadside safety devices should meet the crash 


test and evaluation criteria contained in the American Association of State Highway and 


Transportation Officials' Manual for Assessing Safety Hardware (MASH) or the National 


Cooperative Highway Research Program (NCHRP) Repo1i 350. However, the FHWA, the 


Department of Transpo1iation, and the United States Goverrunent do not regulate the 


manufacture ofroadside safety devices. Eligibility for reimbursement under the Federal-aid 


highway program does not establish approval, certification or endorsement of the device for any 


paiiicular purpose or use. 


This letter is not a determination by the FHWA, the Department of Transportation, or the United 


States Govermnent that a vehicle crash involving the device will result in any particular outcome, 


nor is it a guarantee of the in-service performance of this device. Proper manufacturing, 


installation, and maintenance are required in order for this device to function as tested. 


Archived 

For 

Research 

and 

Historical 

Purposes 

Only
2 

This finding of eligibility is limited to the crash worthiness of the system and does not cover other 

structural features, nor conformity with the Manual on Uniform Traffic Control Devices. 

Eligibility for Reimbursement 

Based solely on a review of crash test results and certifications submitted by the manufacturer, 

and the crash test laboratory, FHWA agrees that the device described herein meets the crash test 

and evaluation criteria of the NCHRP Report 350. Therefore, the device is eligible for 

reimbursement under the Federal-aid highway program if installed under the range of tested 

conditions. 

Name of system: 350 SKT Terminal with MASH SKT Impact Head 

Type of system: W-Bearn Guardrail extruder terminal 

Test Level: 	 NCHRP Report 350 Test Level 3 (TL3) 

Testing conducted by: KARCO, Inc. 

Dates ofrequest: December 22, 2015, revised July 29, 2016 

Date initially acknowledged: December 31 , 2015 and August 23, 20 16 

Date of completed package: September 1, 2016 

FHWA concurs with the recommendation of the accredited crash testing laboratory as stated 

within the attached form. 

Full Description of the Eligible Device 

The device and supporting documentation, including reports of the crash tests or other testing 

done, videos of any crash testing, and/or drawings of the device, are described in the attached 

form. 

Notice 

If a manufacturer makes any modification to any of their roadside safety hardware that has an 

existing eligibility letter from FHWA, the manufacturer must notify FHWA of such modification 

with a request for continued eligibility for reimbursement. The notice of all modifications to a 

device must be accompanied by: 

o 	 Significant modifications - For these modifications, crash test results must be 

submitted with accompanying documentation and videos. 

o 	 Non-signification modifications - For these modifications, a statement from the 

crash test laboratory on the potential effect of the modification on the ability of 

the device to meet the relevant crash test criteria. 

FHWA's determination of continued eligibility for the modified hardware will be based on 

whether the modified hardware will continue to meet the relevant crash test criteria. 

You are expected to supply potential users with sufficient information on design, installation and 

maintenance requirements to ensure proper performance. 

Archived 

For 

Research 

and 

Historical 

Purposes 

Only
3 

You are expected to certify to potential users that the hardware furnished has the same chemistry, 

mechanical properties, and geometry as that submitted for review, and that it will meet the test 

and evaluation criteria of the MASH. 

Issuance of this letter does not convey property rights of any sort or any exclusive privilege. This 

letter is based on the premise that information and reports submitted by you are accurate and 

correct. We reserve the right to modify or revoke this letter if: (1) there are any inaccuracies in 

the information submitted in support of your request for this letter, (2) the qualification testing 

was flawed, (3) in-service performance or other information reveals safety problems, ( 4) the 

system is significantly different from the version that was crash tested, or (5) any other 

information indicates that the letter was issued in error or otherwise does not reflect full and 

complete information about the crash worthiness of the system. 

Standard Provisions 

• 	 To prevent misunderstanding by others, this letter of eligibility designated as FHW A 

control number CC-130 shall not be reproduced except in full. This letter and the test 

documentation upon which it is based are public information. All such letters and 

documentation may be reviewed upon request. 

• 	 This letter shall not be construed as authorization or consent by the FHW A to use, 

manufacture, or sell any patented system for which the applicant is not the patent holder. 

• 	 Ifthe subject device is a patented product it may be considered to be proprietary. If 

proprietary systems are specified by a highway agency for use on Federal-aid projects: 

(a) they must be supplied tlu·ough competitive bidding with equally suitable unpatented 

items; (b) the highway agency must certify that they are essential for synchronization 

with the existing highway facilities or that no equally suitable alternative exists; or ( c) 

they must be used for research or for a distinctive type of construction on relatively short 

sections of road for experimental purposes. Our regulations concerning proprietary 

products are contained in Title 23, Code of Federal Regulations, Section 635.411. 

Sincerely yours, 

Michael S. Griffith 

Director, Office of Safety Technologies 

Office of Safety 

Enclosures 

Archived 

For 

Research 

and 

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Only
Date of Request: July 29, 2016 

Name: Balbino A. Beltran 

I le New ('Resubmission

... 

QI Company: KARCO Engineering, LLC. ..... 

..... ·e 
 Address: 
 9270 Holly Road, Adelanto, CA. 92301 ..0 

:I Country: V) United States 


Michael S. Griffith, Director 
 To: FHWA, Office of Safety Technologies 

Version 10.0 (05/16) 

Page 1 of 8 

Request for Federal Aid Reimbursement Eligibility 

of Highway Safety Hardware 

I request the following devices be considered eligible for reimbursement under the Federal-aid 

highway program. 

Device & Testing Criterion - Enter from right to left starting with Test Level I ' -' -' I 

System Type Submission Type Device Name I Variant Testing Criterion Test 

Level 

'CC': Crash Cushions, 

Attenuators, & Terminals 

('Physical Crash Testing 

le Engineering Analysis 

350 SKT Terminal with 

MASH SKT Impact Head 

NCHRP Report 350 TL3 

By submitting this request for review and evaluation by the Federal Highway Administration, I certify 

that the product(s) was (were) tested in conformity with the NCH RP Report 350 (Report 350) and that 

th e evaluation results meet the appropriate evaluation criteria in the Report 350. 

Individual or Organization responsible for the product: 

Contact Name: Kaddo Kothmann Same as Submitter 0 

Company Name: Road Systems, Inc. Same as Submitter 0 

Address: 3616 Howard County Airport Big Spring, TX 79720 Same as Submitter 0 

Country: United States Same as Submitter 0 

Enter below all disclosures of financial interests as required by the FHWA ' Federal-Aid Reimbursement 

Eligibility Process for Safety Hardware Devices' document. 

Road Systems is the manufacturer and marketer of device. 

KARCO Engineering, LLC is an independent research and testing laboratory having no 

affiliation with any other entity. The company is solely-owned and operated by Mr. Frank D. 

Richardson and Ms. Jennifer W. Peng (husband and wife) and was established on September 

2, 1994. KARCO is actively involved in data acquisition and compliance/certification testing for a 

variety of government agencies and equipment manufacturers. 

The principals and staff of KARCO Engineering have no past or present financial, contractual or 

organizational interest in any company or entity directly or indirectly related to the products that 

KARCO tests. If any financial interest should arise, other than receiving fees for testing, 

reporting, etc., with respect to any project, the company will provide, in writing, a full and 

immediate disclosure to the FHWA. 

Archived 

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Page 2 of 8 

PRODUCT DESCRIPTION 

(' New Hardware or (9 Modification to Non-Significant Significant Modification • Existing Hardware 

The modification under evaluation is the replacement of the existing 350-SKT impact head by the new MSKT 

impact head on existing 350-SKT terminal systems. Given the continuing use of the 350 SKT systems for the 

foreseeable future and the need for repair parts into the future, having a single impact head that is approved 

for all systems will minimize maintenance inventory and potential liability for the States. Refer to Appendix B 

for engineering analysis and component testing. 

CRASH TESTING 

By signature below, the Engineer affi liated with the testing laboratory, agrees in support of this submission that 

the Modification to Existing Hardware is deemed Non-significant for the device listed above to meet the MASH 

criteria. 

Engineer Name: Balbino A. Be ltran 

Digitally signed by Balbino A. Beltran Engineer Signature: BaIbin 0 A Beltran DN,rn=B,lbiooA. BolHoo,o=KARCO Eogio..dog.LLC.,oc, • erna1l=abeltran@karco.com, c=US 

"· -"'" ' n'!n11J':l·di.-.iR .n7'nl'I' 

Address: 9270 Holly Road, Adelanto, CA. 92301 Same as Submitter 

Country: United States Same as Submitter 

A brief description of each crash test and its result: 

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Page 3 of 8 

Required Test Narrative Evaluation 

Number Description Results 

KARCO Test No. P35127-01. An 820C (1,800 

lb) passenger car impacting the terminal 

end-on at a nominal impact speed and 

angle of 100 km/h (62.2 mph) and 0 degree, 

respectively, with the quarter point of t he 

vehicle aligned with the center line of the 

nose of the terminal. This test is primarily 

intended to evaluate occupant risk and 

vehicle trajectory criteria. 

This 3-30 test was conducted with a 350 

SKT-SP MGS steel-post guardrail system, 

SKT-SP-MGS-MS3000, with a MASH SKT 

impact head at a mounting height of 32 in. 

(8 13 mm). 

The test vehicle, a 2000 Chevrolet Metro 3­

door hat chback weighing 1,819.9 lb (825.5 

kg), impacted the 350 SKT terminal head-on 

at an impact speed and angle of 60.64 mph 

(97.59 km/ h) and 0.5 deg ree, respectively. 

3-30 (820C) The vehicle pushed the impact head dow n Modification has no effect on crashworthiness 

the length of the guardra il past Post 4, at 

which point the kinking process stopped 

and the rail began to buckle between posts 

4 and 5. The vehicle rotated counterclockwise before separating from the article 

towards the traffic side at an exit angle of 

21 .0 degrees. The vehicle came to rest 49.9 

ft (15.2 m) forward and 22.5 ft (6.9 m) right 

of the point of initial impact. The test 

vehicle sustained mod erate damage to the 

front end with no occupant compartment 

penetration or deformation. The vehicle 

remained upright during and after the 

impact event. The test article received 

extensive damage from post 1 through post 

4. The Occupant Impact Velocities (OIV) and 

ridedown accelerations are within the 

recommended limits. In summary, the 350 

SKT terminal with a MASH SKT impact head 

passed all evaluation criteria for Test 3-30. 

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Version 10.0 (05/16) 

Page 4 of 8 

Required Test 

Number 


Narrative 

Description 

Evaluation 


Resu lts 

3-30 (820C) 

KARCO Test No. P35226-01. An 820C (1,800 

lb) passenger car impacting the terminal 

end-on at a nominal impact speed and 

angle of 100 km/h (62.2 mph) and 0 degree, 

respectively, with the quarter point of the 

vehicle aligned with the center line of the 

nose of the terminal. This test is primarily 

intended to evaluate occupant risk and 

vehicle trajectory criteria. 

This 3-30 test was conducted with a 350 SKT 


MGS wood-post guardrail system, SKT-WMGS8-MS3000, with a MASH SKT impact 


head at a mounting height of 32 in. (813 


mm). 


The test veh icle, a 1997 Geo Metro 3-door 

hatchback weighing 1,795.8 lb (814.5 kg), 

impacted the SKT terminal head-on at 

impact speed and angle of 60.53 mph 

(97.42 km/h) and 0.2 degree, respectively. 

The vehicle pushed the impact head down 

the length of the guardrail past Post 4 and 

the extruded section of the rail contacted 

Post 5. The kinking process stopped at 

about Post 5 and the vehicle rotated 

counter-clockwise before separating from 

the article toward the traffic side. The 

vehicle came to rest 33.1 ft (10.1 m) forward 

and 4.1 ft (1.2 m) right of its position at the 

point of initial impact. The test vehicle 

sustained moderate damage to the front 

end with no occupant compartment 

penetration or deformation. The vehicle 

remained upright and did not leave its lane. 

The test article received extensive damage 

from post 1 through post 5. The Occupant 

Impact Velocities (OIV) and ridedown 

accelerations are within the recommended 

limits. In summary, the 350 SKT terminal 

with the MASH SKT impact head passed all 

evaluation criteria for Test 3-30. 

Modification has no effect on crashworthiness 

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KARCO Test No. P35225-01. A 2000P (4,400 

lb) pickup truck impacting the terminal endon at a nominal impact speed and angle of 

100 km/h (62.2 mph) and 0 degree, 

respectively, with the center line of the 

vehicle aligned with the center line of the 

nose of the terminal. This test is primarily 

intended to evaluate occupant risk and 

vehicle trajectory criteria. 

This test was conducted with a 350 SKT-SP 


Metric steel-post guardrail system, SKT-SPS-MS3000, with a MASH SKT impact head at 


a mounting height of 27-5/8 in. (702 mm). 


3-31 (2000P) 

The test vehicle, a 2000 Chevrolet Silverado 


2500 2-door pickup truck weighing 4,460.9 


lbs (2,023.5 kg), impacted the 350 SKT 


terminal head-on at impact speed and 


angle of 62.00 mph (99.78 km/h) and 0.5 

degree, respectively. The vehicle pushed 

the impact head down the length of the 

guardrail past Post 8. The kinking process 

stopped some time between Post 7 and 8. 

The vehicle remained in contact with the 

impact head until the vehicle came to rest 

41.4 ft (12.6 m) forward and 0.3 ft (0.1 m) 


left of the point of initial impact. The test 


vehicle sustained moderate damage to the 


front end with no occupant compartment 


penetration or deformation. The vehicle 


remained upright and did not leave its lane. 


The test article received extensive damage 


from Post 1 through Post 8.The Occupant 


Impact Velocities (OIV) and ridedown 


accelerations are within the recommended 


limits. In summary, the 350 SKT terminal 


with a MASH SKT impact head passed all 


evaluation criteria for Test 3-31. 


Modification has no effect on crashworthiness 

3-32 (820() 

NCHRP 350 Test Designation No. 3-32. An 


820( (1,800 lb) passenger car impacting the 


terminal end-on at a nominal impact speed 


and angle of 100 km/h (62.2 mph) and 15 


degrees, respectively, with the center line of 


the vehicle aligned with the center line of 


the nose of the terminal. 


For the evaluation of replacing the 350 

impact head with the MASH impact head, 

this head-on angle crash test (Test 3-32) is, 

in our opinion, non-critical and not 

necessary for this specific evaluation. The 

rationale for our opinion is presented in 

Attachment B. 

Non-Relevant Test, not conducted 

S3-32 (700() Test not necessary for component testing. Non-Relevant Test, not conducted 

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Version 10.0 (05/16) 

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3-33 (2000P) 

NCH RP 350 Test Designation 3-33. A 2000P 

(4,400 lb) pickup truck impacting the 

terminal end-on at a nominal impact speed 

and angle of 100 km/h (62.2 mph) and 15 

degrees, respectively, with the center line of 

the vehicle aligned with the center line of 

the nose of the terminal. 

For the evaluation of replacing the 350 

impact head with the MASH impact head, 

this head-on angle crash test (Test 3-33) is, 

in our opinion, non-critical and not 

necessary for this specific evaluation. The 

rationale for our opinion is presented in 

Attachment B. 

Non-Relevant Test, not conducted 

3-34 (820() 

NCH RP 350 Test Designation No. 3-34. An 

820( (1,800 lb) passenger car impacting the 

terminal at a nominal impact speed and 

ang le of 100 km/ h (62.2 mph) and 15 

degrees, respectively, with the corner of the 

vehicle bumper aligned with the critical 

impact point (CIP) of the length of need 

(LON) of the terminal. This test is primarily 

intended to evaluate occupant risk and 

vehicle trajectory criteria. 

Since the modification under evaluation 

involves only the replacement of the impact 

head, it would have no effect on this CIP 

redirection test 3-34. Thus, this test is 

considered irrelevant and excluded from 

the crash test matrix. 

Non-Relevant Test, not conducted 

S3-34 (700() Test not necessary for component testing. Non-Relevant Test, not conducted 

3-35 (2000P) 

NCH RP 350 Test designation No. 3-35. A 

2000P (4,400 lb) pickup truck impacting the 

terminal at a nominal impact speed and 

angle of 100 km/h (62.2 mph) and 20 

degrees, respectively, with the corner of the 

vehicle bumper aligned with the beginning 

of the length-of-need (LON) of the terminal. 

This test is primarily intended to evaluate 

structural adequacy and vehicle trajectory 

criteria. 

Since the modification under evaluation 

involves only the replacement of the impact 

head, it would have no effect on this LON 

redirection test 3-35. Thus, this test is 

considered irrelevant and excluded from 

the crash test matrix. 

Non-Relevant Test, not conducted 

3-36 (820() Test not relevant for component testing. Non-Relevant Test, not conducted 

S3-36 (700() Test not relevant for component testing. Non-Relevant Test, not conducted 

3-37 (2000P) Test not relevant for component testing. Non-Relevant Test, not conducted 

3-38 (2000P) Test not relevant for component testing. Non-Relevant Test, not conducted 

Archived 

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Version 10.0 (05/16) 

Page 7 of 8 

3-39 (2000P) 

NCH RP 350 Test Designation 3-39. A 2000P 

(4,400 lb) pickup truck impacting the 

terminal at a nominal impact speed and 

angle of 62.2 mph (100 km/ h) and 20 

degrees, respectively, at the midpoint 

between the nose and the end of the 

terminal in the reverse direction. This test is 

intended to evaluate the performance of a 

terminal for a "reverse" hit. Non-Relevant Test, not conducted 

Since the modification under evaluation 

involves only the replacement of the impact 

head, it would have no effect on this reverse 

direction test 3-39. Thus, thi s test is 

considered irreleva nt and excluded from 

the crash test matrix. 

3-40 (2000P) Test not relevant for component testing. Non-Relevant Test, not conducted 

53-40 (700C) Test not relevant for component testing. Non-Relevant Test, not conducted 

3-41 (2000P) Test not relevant for component testing. Non-Relevant Test, not conducted 

3-42 (820C) Test not relevant for component testing. Non-Relevant Test, not conducted 

S3-42 (700C) Test not relevant for component testing. Non-Relevant Test, not conducted 

3-43 (2000P) Test not relevant for component testing. Non-Relevant Test, not conducted 

3-44 (2000P) Test not relevant for component testing. Non-Relevant Test, not conducted 

Testing Laboratory's signature concurs that these modifications are considered Non-Significant . 

Laboratory Name : KARCO Engineering, INC 

Laboratory Signature: Balbino A. Beltran .., DN: cn=Ba lbinu A Beltran, o=KARCO Engi neering, LL(., ou. 

email =abeltran@karco.co m,c=US 

Da te: 201 6.08.01 18:47: 16 -07'00' 

··­

Address: 9270 Holly Road, Adelanto, CA. 92301 Same as Submitter 1:8:1 

Country: United States Same as Submitter 1:8:1 

Accreditation Certificate 

Number and Dates of current 

Accreditation period : 

TL-371 , December 18, 2015 through December 18, 2017 

OigltaHy§lgn~byBalb noA. Beltran 

Submitter Signature*: Ba Ibi n0 A. BeItr a n N~.~:: ~:! ~!~ ~~;· ~~'~,:~ ~l~eerlng, Date:2016.0S.011 8:47:S3·07'00' 

Submit Form 

ATTACHMENTS 


Archived 

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Only
Version 10.0 (05/16) 

Page 8 of 8 

Attach to this form: 

1) Additional disclosures ofrelated financial interest as indicated above. 

2) A copy of the full test report, video, and a Test Data Summary Sheet for each test conducted in 

support ofthis request. 

3) A drawing or drawings ofthe device(s) that conform to the Task Force-13 Drawing Specifications 

[Hardware Guide Drawing Standards]. For proprietary products, a single isometric line drawing is 

usually acceptable to illustrate the product, with detailed specifications, intended use, and contact 

information provided on the reverse. Additional drawings (not in TF-13 format) showing details that 

are relevant to understanding the dimensions and performance ofthe device should also be submitted 

to facilitate our review. 

FHWA Official Business Only: 

Eligibility Letter 

Number Date Key Words 

Archived 

For 

Research 

and 

Historical 

Purposes 

Only
Tl-3 

TL-2 

Wood Post Systems 

(2, 4, or 8 Tubes) 

Rail Height 28" - *31" 

*Blocks may be 8" or 12" Deep 

= 

TL-3 


TL-2 


Hinged/Plug Welded System 

Posts 3-8 May be Hinged or 

Plug Welded 

Rail Height 28" - *31" 

*Blocks may be 8" or 12" Deep 

= 

= 

Tl - 3 

TL-2 

Plug Welded System 

(2, 4, or 8 Tubes) 

Rail Height 28" - *31" 

•Blocks may be 8" or 12" Deep 

TL-3 


TL-2 


SP Steel Post 


Rail Height 28" - *31" 


= 

* Blocks may be 8" or 12" Deep 

END PANELS SECOND RAIL 

12'-6" for 28" through 30" rail heights 12'-6" for 28" through 30" rail heights 

25' for 28" through 30" rail heights 

12'-6" for 31" ra il heights (a ) 

15'-7 1/2" for 31" rail heights (b) 

25' for 28" through 30" rail heights 

(a) 9'-4 1/2" for 31" rail heights 

(a) 15'-7 1/2" for 31" rail heights 

(b) 12'-6" for 31" rail heights -~S-I=-

Road Systems, Inc. 

MSKT Impact Head 

Applicability for 

NCHRP 350 Terminals 

Sheet: 

Date: 

08/30/16 

By: 

JRR 

Bfi Sprfn&, TI Drawi ng Name: Scale: Rev: 

Phone: 432-263-2435 MSKT Replacement None 0 

Archived 

For 

Research 

and 

Historical 

Purposes 

Only
I I 

o =-t11t---+--If'F 

11 i I i 

!L. - ­ ___L_J

0

,_, ~ c=) TRAFFIC SIDE

' e&J 

/ 0/~I

I 
rA

! [ 

0 

0 

'[<I 

I 11 

1 ­ it=::::­

' 

I 

' 

D 

~ 

I I Road Systems, Inc. 

Big Spring, TX Drawing Name: Phone: 432-263-2435 

or Phone: 330-346-0721 

' 

v .

-,

t 

~ 

~--------J ' 

i 

I ~ ~ 

I 

' A c=) I ~ 

\ __,! [)=

I -------- --:::: 'fl 

TRAFFIC SIDE 

r 

I 

, l BACKSIDE 

BACKSIDE 

MASH SKT 


IMPACT HEAD 


"'1•· 

MS3000 NONE 

Sheet: 

1 

Date: 

02/15/15 

B~R R I"&, 

Archived 

For 

Research 

and 

Historical 

Purposes 

Only
ATTACHMENT B 

350 SKT TERMINAL SYSTEMS WITH MASH SKT IMPACT HEAD 

CRASH TEST MATRIX 

INTRODUCTION 


A new MSKT terminal has been successfully crash tested under the MASH guidelines and will be 

submitted to FHWA for review within the next few weeks. With the introduction ofthe MSKT tem1inal, 

the State DOTs will be faced with the problem of maintaining inventory oftwo different impact heads 

and training their personnel to use one impact head for installation and a differing one for 

maintenance/repair operations. Given that there are in excess of200,000 350-SKT terminals in service it 

would be ideal if all future installations, as we! 1as repairs of 350-SKT terminals, could use the same 

MSKT impact head . The objective of this series of full-scale crash tests is to demonstrate the satisfactory 

impact performance of replacing the current 350-SKT impact head with the MSKT impact head for all 

new and repaired 350-SKT terminal systems. 

While the new MSKT impact head offers significant safety improvements, having met all MASH 

testing criteria, it is very similar to the 350-SKT impact head in terms ofthe dimensions of the deflector 

plate and layout ofthe feed chute. While these changes could be considered minor in terms of 

performance, Road Systems, Inc., citing the significance of this change to the market, asked that the 

performance of MSKT heads on existing 350-SKT systems be confirmed with full-scale testing. 

Selection of Test System 

There are numerous approved configurations of 350-SKT terminal system, thus it is necessary to 

select the most critical systems for use in evaluation ofthe performance of the MSKT impact head. To 

evaluate the broadest range of conditions there are four primary factors: 1) post configuration, 2) system 

height, 3) rail configuration and 4) block out depth. 

I) Post Configuration: 

Road Systems, lnc. offers several steel hinged post systems along with a system utilizing standard 

W6x9 line posts at and downstream of Post #3. Breakaway or hinged posts are designed to break away at 

given force levels for predictable breakaway behavior, thus it is well understood that standard steel line 

posts pose more of a risk. Since standard steel line posts do not break away, there is greater potential for 

adverse effects on occupant safety and vehicle kinematics. The fewer breakaway posts a terminal system 

has, the more critical it is from a performance standpoint. The steel-post 350-SKT standard post (SP) 

system has only two breakaway posts followed by standard steel line posts from Post #3 on and therefore 

it is considered the most critical among the approved steel-post systems. 

There are also approved wood-post 350-SKT systems with differing numbers ofBCT and CRT 

posts. These systems are comprised of two foundation tube anchors connected with a strut followed by a 

series of either BCT or CRT posts downstream. Downstream ofthe anchor, CRT posts that are directly 

embedded in soil have a higher propensity to rotate than a BCT posts in foundation tubes. This rotation of 

the CRT posts upon impact may destabilize a small passenger car (820C) and adversely affect the 

Archived 

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Purposes 

Only
resulting vehicle trajectory. Therefore a system with CRT posts from Post #3 on was considered to be the 

most critical case. 

2) 	 System Height: 

Existing 350-SKT systems have been approved for system heights ranging from 27-5/8 in. (702 

mm) to 32 in. (813 mm). The highest and lowest extremes were selected to demonstrate the effectiveness 

of using MSKT impact heads on existing 350-SKT systems for all rail heights. Systems with the 27-5/8 in. 

(702 mm) rail height have been shown to be critical for pickup truck crash tests since they increase the 

potential for the pickup truck to override the impact head and rail. In contrast, 32 in. (813 mm) rail height 

systems have been shown to be more critical for small car crash tests since they increase the potential for 

the vehicle to underride the impact head and rail. Thus, a rail height of 32 in. (813 mm) was used for the 

small car crash tests while a rail height of 27-5/8 in. (702 mm) was used for the pickup truck crash test. 

3) 	 Rail Confi guration: 

The 350-SKT system has a variety of approved options for the location of the first splice. 

Increased force is required to feed spliced sections through the impact head. Therefore, the closer this 

location is to the upstream end of the system, the more critical its impact on performance is. Thus, all tests 

were conducted with the initial rail splice at Post #3, the most upstream location in the approved 350-SKT 

systems. 

4) 	 Block Depth: 

Both 8-in. (203-mm) and 12-in. (305-mm) blocks have been approved for specific 350-SK T 

systems. The depth of the blocks has been shown to have negligible impact in head-on and head-on angle 

tests; however, in redirection tests the 8-in. (203 mm) block has been shown to have a higher potential for 

tires of the vehicle to contact and snag on the posts. Thus, in keeping with the philosophy of testing the 

most critical systems, all tests were conducted with 8-in. (203-mm) blocks. 

Selection of Crash Test Matrix 

Three crash tests were conducted to evaluate the impact performance of the MSKT impact head when 

used with the 350-SKT terminal systems: 

1. 	 Test 3-30. An 820-kg (1800-lb) passenger car impacting the terminal head-on with a one-quarter 

offset at a speed and angle of 100 km/h (62.2 mph) and 0 degree. The test system was selected to 

be a steel-post 350-SKT standard post (SP) system with a rail height of 32 in. (813 mm). 

2. 	 Test 3-31. A 2000-kg ( 4400-lb) pickup truck impacting the terminal head-on at a speed and angle 

of 100 km/h (62.2 mph) and 0 degree. The test system is selected to be a steel-post 350-SKT 

standard post (SP) system with a rail height of27-5/8 in. (702 mm). 

3. 	 Test 3-30. An 820-kg (1800-lb) passenger car impacting the terminal head-on with a one-quarter 

offset at a speed and angle of I 00 km/h (62.2 mph) and 0 degree. The test system is selected to be 

a wood-post 350-SKT system with a rail height of32 in. (813 mm). 

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NCH RP 350 guidelines specify up to seven crash tests to evaluate a guardrail terminal system. 

Since the modification under evaluation involves only the replacement ofthe impact head, only those 

tests that are potentially affected by changing the impact head were considered (Tests 3-30, 3-31, 3-32 

and 3-33). 

Tests 3-32 and 3-33 were determined to be unnecessary, given the similarity ofthe MSKT and 

the 350-SKT impact heads. The geometry and force levels ofthe two impact heads are nearly identical 

and the original Test 3-32 ofthe 350 SKT terminal (Test SBD-5)(Jl, clearly demonstrates (Figures 1 &2) 

that because ofthe 15 degree initial impact angle, the vehicle gates behind the guardrail before the 

buckled rail or the elbow would pose a hazard to the vehicle. 

It is also to be noted that the MSKT terminal has successfull y passed Test 3-32 and 3-33 under 

MASH criteria with an impact angle of 5 degrees, cited in the repod2 

> by the AASHTO-FHWA .Joint 

Task Force on Guardrail Terminal Crash Analysis as a critical performance criteria for compression 

terminals. 

References 

I. 	 Strybos, J. W., and Mayer, J. B., "Full-Scale Crash Evaluation of A Sequential Kinking Terminal 

(SKT-350)," Southwest Research Institute, San Antonio, Texas, March 1997. 

2. 	 "Safety Analysis of Extruding W-Beam Guardrail Terminal Crashes," Report by .Joint AASHTOFHWA Task Force on Guardrail Terminal Crash Analysis, Washington, D. C., September 2015. 

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' , 


Figure I. Sequential Overhead Photographs 350 SKT Test 3-32. 

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; 

Figure 2. Sequential Photographs 350 SKT Test 3-32. 

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