1200 New Jersey Ave., SE

 Washington, D.C. 20590

May 4, 2012 

FHWA: HSST: NArtimovicht: sf: x61331:3/27/12: Revised 5/3/12

File: s: //directory folder/HSST/Artimovich/SS-175

cc: HSST (NArtimovich; JDewar) 

In Reply Refer To:

SS-175

Greg Kirchgesner

Xcessories Squared

P.O. Box 135

Auburn, Illinois 62615

Dear Mr. Kirchgesner:

This letter is in response to your request for the Federal Highway Administration (FHWA) to 

review a roadside safety system for eligibility for reimbursement under the Federal-aid highway 

program. 

Name of system: Surface Mount Slip Bases SMSB10-10-G and SMSB8-10-G 

Type of system: Triangular Slip Base Small Sign Support for Perforated 

Square Steel Tube (PSST) posts

Test Level: NCHRP Report 350 Test Level 3

Testing conducted by:N/A 

Date of request: June 28, 2011

Decision:

The following devices are eligible, with details provided below

• Surface Mount Slip Bases SMSB10-10-G and SMSB8-10-G 

Based on a review of the information and calculations submitted by the manufacturer certifying 

the device described herein meets the crash test and evaluation criteria of the National 

Cooperative Highway Research Program (NCHRP) Report 350, the device is eligible for 

reimbursement under the Federal-aid highway program. Eligibility for reimbursement under the 

Federal-aid highway program does not establish approval or endorsement by the FHWA for any 

particular purpose or use. 

The FHWA, the Department of Transportation, and the United States Government do not 

endorse products or services and the issuance of a reimbursement eligibility letter is not an 

endorsement of any product or service.

Requirements

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

and evaluation criteria contained in the National Cooperative Highway Research Program 

(NCHRP) Report 350 or the American Association of State Highway and Transportation 

Officials’ Manual for Assessing Safety Hardware (MASH). 
2

Description

You requested our review of two new slip base components that would work with your NCHRP 

Report 350 compliant Slip Base Tops and would use your Redi-Torque Hardware. The 8-inch 

version has the same geometry as your existing 8-inch Slip Base Tops, and the 10 3/8-inch 

version that has the same geometry as your existing 10 3/8-inch Slip Base Tops. You provided

calculations (enclosed for reference) that show that both of the Surface Mount Slip Bases are 

stronger than the posts that they would support. They would be secured to flat concrete surfaces 

using standard concrete anchors that would be required to exceed the load capacities of the slip 

base & sign assembly to ensure proper functionality of the slip bases. The surface mount allows 

for installations on top of concrete medians instead of coring a large hole into them, when a slip 

base is desired in place of other sign post mounting devices. This mounting system is similar to 

the rigid foundations used when larger sized slip bases are crash tested.

Summary and Standard Provisions

Therefore, the systems described above and detailed in the enclosed drawings are eligible for 

reimbursement and may be installed under the range of conditions tested. 

Please note the following standard provisions that apply to FHWA eligibility letters:

• This finding of eligibility does not cover other structural features of the systems, nor 

conformity with the Manual on Uniform Traffic Control Devices.

• Any changes that may influence system conformance with NCHRP Report 350 criteria 

will require a new reimbursement eligibility letter.

• Should the FHWA discover that the qualification testing was flawed, that in-service 

performance reveals safety problems, or that the system is significantly different from the 

version that was crash tested, we reserve the right to modify or revoke this letter.

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

installation requirements to ensure proper performance.

• 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 crash test and evaluation criteria of the NCHRP Report 350.

• To prevent misunderstanding by others, this letter of eligibility is designated as number 

SS-175 and 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 at our office upon request. 
3

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

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

The FHWA does not become involved in issues concerning patent law. Patent issues, if 

any, are to be resolved by the applicant.

Sincerely yours,

Michael S. Griffith

Director, Office of Safety Technologies

Office of Safety

Enclosures