USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation
FHWA Highway Safety Programs

Safety Eligibility Letter SS-175

Hardware Type:
Sign Supports, Mailboxes, and Delineator Posts
Code:
SS-175
Date:
Testing Criteria:
NCHRP 350
Manufacturer:
Xcessories Squared
Device Description:
Surface Mount Slip Bases SMSB10-10-G and SMSB8-10-G
View PDF:
ss175.pdf (417.38 KB)

Safety Eligibility Letter SS-175 - Safety

Download Version
PDF [417 KB]

DOT logo
U.S. Department of Transportation
Federal Highway Administration

1200 New Jersey Ave. S.E.
Washington, D.C. 20590

May 4, 2012

In Reply Refer To:
HSST/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).

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. 
  • 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,

/* Signature of Michael S. Griffith */

Michael S. Griffith
Director, Office of Safety Technologies
Office of Safety

Enclosures