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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-163

Hardware Type:
Sign Supports, Mailboxes, and Delineator Posts
Code:
SS-163
Date:
Testing Criteria:
NCHRP 350
Manufacturer:
Information Display Company
Device Description:
IDC Speed Check Radar Speed Display Devices
View PDF:
ss163.pdf (2.41 MB)
Download Version
PDF [2,543 KB]

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

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

April 2, 2010

In Reply Refer To: HSSD/SS-163

Mr. Gary ODell, President
Information Display Company
10950 SW 5th Street, Suite 330
Beaverton, OR 97005

Dear Mr. ODell:

Thank you for your letter of September 14, 2009, requesting the Federal Highway Administration’s (FHWA) acceptance of your company’s Speed Check models VSC-1520 and VSC-1820 radar speed displays mounted to a breakaway pole as a crashworthy sign support system for use on the National Highway System (NHS). Accompanying your letter was an engineering analysis report that included calculations verifying the display connection strength, reference to previous crash tests of similar devices, and drawings of the system. You requested that we find the Speed Check systems acceptable for use on the NHS under the provisions of the National Cooperative Highway Research Program (NCHRP) Report 350 “Recommended Procedures for the Safety Performance Evaluation of Highway Features.”

The Speed Check VSC-1520, is a radar speed display with 15 inch digit height, and the VSC-1820 has a display with 18 inch digit height. The VSC-1520 weighs 51 pounds and the VSC-1820 weighs 62 pounds. The models are described in further detail in the enclosed engineering analysis report. Each radar speed display is attached to a 4-inch diameter pole and the bottom of the unit is mounted at least 84 inches from the ground using a minimum of 3/8-inch diameter U bolts made of A307 steel as shown in the enclosed report.

You referenced FHWA Acceptance Letters, SS-84, dated July 26, 1999, and SS-121, dated December 30, 2003, in which motorist aid call boxes were tested on poles mounted on 4-bolt slip bases. The call boxes were of weights slightly heavier than the Speed Check devices but mounted closer to the ground, near windshield height. In these test programs the occupant impact speeds and decelerations were well within limits, as was occupant compartment deformation (roof crush). However, in SS-84 the call boxes were mounted on the side of the support post and in SS-121 they were located on the backside of the post. The Speed Check sign units will be mounted on the post facing oncoming traffic and are therefore more likely to break free from the support post upon impact. The enclosed report with calculations shows the strength of the bolts is adequate to absorb the anticipated impact.

Based on the results of your calculations and the previous testing referenced above, the Speed Check installations are comparable and likely to meet the breakaway criteria under the NCHRP Report 350. Therefore, the devices described above and shown in the enclosed drawings for reference are acceptable for use as test level 3 devices on the NHS under the range of conditions tested, when proposed by a State. This acceptance will be limited to a generic four-bolt slip base or a comparable breakaway base using crashworthy, frangible couplings or frangible bases.

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

  • Our acceptance is limited to the crashworthiness characteristics of the devices and does not cover their structural features, nor conformity with the Manual on Uniform Traffic Control Devices.
  • Any changes that may adversely influence the crashworthiness of the device will require a new acceptance letter.
  • Should the FHWA discover that the qualification testing was flawed, that in-service performance reveals unacceptable safety problems, or that the device being marketed is significantly different from the version that was crash tested, it reserves the right to modify or revoke its acceptance.
  • You will be expected to supply potential users with sufficient information on design and installation requirements to ensure proper performance.
  • You will be expected to certify to potential users that the hardware furnished has essentially the same chemistry, mechanical properties, and geometry as that submitted for acceptance, and that they will meet the crashworthiness requirements of the FHWA and the NCHRP Report 350.
  • To prevent misunderstanding by others, this letter of acceptance, designated as number SS-163, shall not be reproduced except in full. As this letter and the supporting documentation which support it become public information, it will be available for inspection at our office by interested parties.
  • The Speed Check speed displays are patented devices and considered “proprietary.” When proprietary devices are specified by a highway agency for use on Federal-aid projects they: (a) must be supplied through competitive bidding with equally suitable unpatented items; (b) the highway agency must certify that they are essential for synchronization with 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, a copy of which is enclosed.
  • This acceptance letter shall not be construed as authorization or consent by the FHWA to use, manufacture, or sell any patented device for which the applicant is not the patent holder. The acceptance letter is limited to the crashworthiness characteristics of the candidate device, and the FHWA is neither prepared nor required to become involved in issues concerning patent law. Patent issues, if any, are to be resolved by the applicant.
 

Sincerely yours,

/* Signature of David A. Nicol */

David A. Nicol, P.E.
Director, Office of Safety Design
Office of Safety

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