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Publication Number: FHWA-RD-99-065
Date: December 1999

NCHRP Report 350 Test 4-12 of the Modified Thrie Beam Guardrail




This report will be of interest to those State and local highway officials who select, locate, and design traffic barriers. It documents the results of a crash test of a Modified Thrie Beam guardrail with an 8000–kg single unit truck impacting at a nominal speed and angle of 80 km/h and 15 degrees. This is the strength test for Test Level Four (TL–4) in NCHRP Report 350. It was found that the test results met all of the evaluation criteria. The single unit truck was smoothly redirected and remained upright.

Detailed drawings are presented for documentation and to facilitate implementation.

Michael F. Trentacoste
Michael F. Trentacoste
Director, Office of Safety
Research and Development


NCHRP Report 350 Test 4-12 of the Modified Thrie Beam Guardrail

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1. Report No.


2. Government Accession No. 3. Recipient's Catalog No.
4. Title and Subtitle

NCHRP Report 350 Test 4-12 of the Modified Thrie Beam Guardrail

5. Report Date
6. Performing Organization Code
7. Author(s)

C. Eugene Buth and Wanda L. Menges

8. Performing Organization Report No.


9. Performing Organization Name and Address

Texas Transportation Institute
The Texas A&M University System
College Station, Texas 77843–3135

10. Work Unit No. (TRAIS)
11. Contract or Grant No.


12. Sponsoring Agency Name and Address

Office of Safety and Traffic Operations
Research and
Federal Highway Administration
6300 Georgetown Pike
McLean, Virginia 22101–2296

13. Type of Report and Period Covered

Test Report
July 1997 – July 1998

14. Sponsoring Agency Code
15. Supplementary Notes

Project conducted in cooperation with the Federal Highway Administration.
Research Study Title: Assessment of Existing Roadside Safety Hardware – II
Contracting Officer's Technical Representative (COTR): Charles F. McDevitt – HSR–20

16. Abstract

The modified thrie beam guardrail has been successfully tested at Test Level 3 (TL–3) of NCHRP Report 350.(3) FHWA decided that the guardrail should be tested to TL–4, which involves a crash test with the 8000S (single–unit truck) traveling at a nominal speed and angle of 80 km/h and 15 degrees, impacting the critical impact point. This test is intended to evaluate the strength of the section in containing and redirecting the pickup truck.

This report presents the details and results of NCHRP Report 350 test destination 4–12 for evaluation of the modified thrie beam to TL–4. The modified thrie beam guardrail met all requirements for NCHRP Report 350 test designation 4–12.

17. Key Words

Guardrail, heavy vehicles, single-unit truck, crash testing, roadside safety.

18. Distribution Statement

No restrictions. This document is available to the public through the National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161.

19. Security Classification (of this report)


20. Security Classification (of this page)


21. No. of Pages


22. Price

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized



United States Department of Transportation - Federal Highway Administration