USA Banner
  U.S. flag
              An official website of the United States government Here's how you knowOfficial 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** ( A locked padlock ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites. 
 U.S. Department of Transportation Icon United States Department of Transportation
 Search DOT
            Search
                    About FHWAFHWA Organization
                Headquarters Offices
                Field Offices
                Strategic Plan
                Business Opportunities
                Staff Directories
                Careers
                Highway History
                Contact UsProgramsAcquisition Management
                Civil Rights
                Federal Lands Highway
                Infrastructure
                Innovative Program Delivery
                Operations
                Planning, Environment, and Realty
                Policy
                Research, Development, and Technology
                Safety
                Browse by TopicsResourcesCore Highway Topics
                Federal Aid Essentials
                Automation
                Complete Streets
                Laws and Regulations
                Policy & Guidance Center
                Section 508
                Publications and Statistics
                Professional Development
                National Highway Institute
                Resource Center
                Accessibility Resource Library
                FHWA Research LibraryNewsroomPress Releases
                Speeches & Testimony
                Photos
                Videos
                Media ContactsMenu FHWA Highway Safety Programs Home
                        Safety
                        Roadway Departure Safety
                        Reduce Crash Severity
                        Hardware Eligibility Letters


            
            In This Section
        Roadway Departure Safety
                Strategic Approach
                                Strategic Plan
                Crash Emphasis Brochures
                Focused Approach
                Noteworthy Practices
                Partner Resources
                Keep Vehicles on the Road
                                Pavement Friction
                Horizontal Curve Safety
                Rumble Strips and Rumble Stripes
                Nighttime Visibility
                Provide for a Safe Recovery
                                SafetyEdge
                Clear Zones
                Reduce Crash Severity
                                Overview
                Hardware Eligibility Letters
                Focus on Reducing Rural Roadway Departures (FoRRRwD)
                                Overview
                All Public Roads
                Proven Countermeasures
                Systemic Approach
                Safety Action Plans
                FoRRRwD Resources
                
                Safety Eligibility Letter SS-07
  
  **Hardware Type:**
            Sign Supports, Mailboxes, and Delineator Posts
                          **Code:**
            SS-07
                          **Date:**
            09/01/1988
                          **Testing Criteria:**
            NCHRP 350
                                  **Device Description:**
            Wisconsin Large Sign Support System - slip base w/no upper hinge, sign  attachment clips provide for release, W12x22 posts tested
                          **View PDF:**
            ss07.pdf (82.61 KB)
    
    United States Department of Transportation - Federal Highway Administration

September 1, 1988

Mr. Frank M. Mayer
Madison, Wisconsin

Your office received direct a copy of Mr. Betsold's August 2, 1988 submittal, which transmitted results from recent crash testing of two large sign assemblies. Tested as 20 and 60 MPH with an 1800 lb. Vehicle were a 15' x 11' sign supported by a pair of W12 x 16 steel supports (Wis Type B) and a 22' x 14' sign on W12 x 22 steel supports (Wis Type D). Signss and supports were of conventional breakaway design with the significant exception of having no fuse plates.

As Mr. Betsold's memorandum notes, the testing shows these supports to meet all of the requirements of the 1985 specifications. In the absence of the fuse plate, failure at acceptable force levels was achieved through separation of the clip system holding the extruded sign panels to the W beam supports. Given developments in sign design over time, the torsional resistance of an extruded aluminum panel is significantly different that the wood or composite sign panels likely used in the earlier testing that led to the incorporation of a fuse plate. Blow over problems led Wisconsin to eliminate the fuse plate but test results would indicate greater sign damage can then be expected from actual roadside collisions.

These test results have been discussed with Mr. Hatton (HNG-14). Both of our offices see no problems in Wisconsin's use (or that by other States) of sign designs within the size parameters of the tested configurations. Important to the overall design of such sign systems is also replicating the tested clip and extruded panel fixation system.

We see no questions as to the Federal-aid eligibility for such sign support systems. Wisconsin (without Federal-aid) over the past 10 years has acquired some actual field experience with this system. Given that the controlled testing is limited to four tests, some States may wish to initially approach application of this design through experimental projects. Such an approach would seem reasonable but is not mandatory. Further, we see no reason for States experiencing satisfactory performance with fuse plates to alter their designs.

We appreciate the professional approach of WisDOT in proceeding to acquire these test results as well as the close cooperation by your office in assisting them. In the long term we expect researchers will build upon these findings to perfect multi-directional breakaway assemblies. State contributions from such efforts as the WisDOT funded testing and through pooled-fund studies will speed this process.

Signed,

Lionel H. Wood, Director
Office of Engineering & Operations

cc:
HNG-14
HSR-20

FHWA Safety Home| FHWA Home | Feedback

FHWA

United States Department of Transportation - Federal Highway Administration U.S. DEPARTMENT OF TRANSPORTATION

**Federal Highway Administration**

1200 NEW JERSEY AVENUE, SE

WASHINGTON, DC 20590

202-366-4000Subscribe to email updates
                    About
  

        
              About FHWA
                Careers
                Org Chart
                Staff Directories
                Work with UsPrograms
  

        
              Acquisition Management
                Civil Rights
                Federal Lands Highway
                Infrastructure
                Innovative Program Delivery
                Operations
                Planning, Environment, and Realty
                Policy
                Research, Development, and Technology
                SafetyPolicies, Rights, Legal
  

        
              About DOT
                Accessibility
                Budget and Performance
                Civil Rights
                FOIA
                Information Quality
                No FEAR Act
                Office of Inspector General
                Privacy Policy
                USA.gov
                Web Policies and Notices
                Web StandardsNews & Events
  

        
              Newsroom
                Press Releases
                Speeches & Testimony
                Media Contacts
                Connect with Us