Development of a Flared Energy-Absorbing Terminal for W-Beam Guardrails

Abstract

A new flared W-beam guardrail terminal that incorporates energy-absorbing technology has been developed and successfully crash tested to meet the criteria presented in NCHRP Report 350. The terminal, designated FLEAT-350, incorporates an impact head designed to dissipate impact energy by producing a series of plastic hinges in the W-beam as the impact head is pushed down the guardrail. The energy-absorption mechanism allows the flared terminal to absorb large amounts of kinetic energy before the vehicle is allowed to gate through the system. Most components of the new terminal are similar to those incorporated in the SKT-350 terminal. The terminal system is 11.4 m (37.5 ft) long and incorporates a straight flare with a final end offset of between 0.76 m (2.5 ft) and 1.2 m (4 ft). The terminal uses two breakaway posts in foundation tubes and five rough-cut controlled-release terminal posts of 150 by 200 mm (6 by 8 in.). The energy-absorbing design minimizes problems associated with vehicles that penetrate the terminal and strike slopes, ditches, or other hazards behind the guardrail while still traveling at a high rate of speed. Furthermore the new design has fewer components and is less sensitive to post location and installation details than some other flared systems.

Get full access to this article

View all access options for this article.

References

Ross

H. E.

, Sicking

D. L.

, Zimmer

R. A.

, and Michie

J. D.

. NCHRP Report 350: Recommended Procedures for the Safety Performance Evaluation of Highway Features. TRB, National Research Council, Washington, D.C., 1993.

Hutchinson

J. W.

, and Kennedy

T. W.

. Medians of Divided Highways—Frequency and Nature of Vehicle Encroachments. Engineering Experiment Station Bulletin 487. University of Illinois, Champaign, June 1966.

Cooper

Analysis of Roadside Enchroachments—Single Vehicle Run-off-the Road Accident Data Analysis for Five Provinces. British Columbia Research Council, Vancouver, British Columbia, Canada, March 1980.

Miaou

S. P.

Measuring the Goodness of Fit of Accident Prediction Models. Report FHWA-RD-96-040. FHWA, U.S. Department of Transportation, Washington, D.C., Dec. 1996.

Griffin

L. I.

III. , Analysis of Accidents on Turned Down Guardrail Ends in the State of Texas. Report 9901-H. Texas Transportation Institute, Texas A&M University System, College Station, 1991.

Gattis

J. L.

, Varghese

J. P.

, and Toothaker

L. E.

. Analysis of Guardrail-End Accidents in Oklahoma. In Transportation Research Record 1419, TRB, National Research Council, Washington, D.C., 1993, pp. 52–62.

Bronstad

M. E.

, and Michie

J. D.

. NCHRP Research Results Digest 102: Modified Breakaway Cable Terminals for Guardrails and Median Barrier. TRB, National Research Council, Washington, D.C., 1978.

Meczkowski

L. C.

Evaluation of Improvements to Breakaway Cable Terminals. Report FHWA-RD-91-065. FHWA, U.S. Department of Transportation, Washington, D.C., 1991.

Sicking

D. L.

, Qureshy

A. B.

, and Ross

H. E.

Jr. Development of Guardrail Extruder Terminal. In Transportation Research Record 1233, TRB, National Research Council, Washington, D.C., 1989, pp. 34–42.

10.

Pfeiffer

B. G.

, and Sicking

D. L.

. Development of a Metal Cutting Guardrail Terminal. Final Report to Interstate Steel Co., Report TRP-03-43-94. Midwest Roadside Safety Facility, University of Nebraska-Lincoln, Sept. 1994.

11.

Sicking

D. L.

, Reid

J. D.

, and Rohde

J. R.

. Development of a Sequential Kinking Terminal for W-Beam Guardrails. In Transportation Research Record 1647, TRB, National Research Council, Washington, D.C., 1998, pp. 89–96.

12.

ET-2000 Accident Data, Ohio Department of Transportation, Columbus, Ohio, 1994.

13.

Kimball

C. E.

, and Mayer

J. B.

. Full-Scale Crash Evaluation of Flared Energy Absorbing Terminal. Southwest Research Project 06-1433, Final Report. Southwest Research Institute, San Antonio, Tex., March 1998.

14.

Sicking

D. L.

, and Keller

E. A.

. Full-Scale Crash Evaluation of a Flared Energy Absorbing Terminal (FLEAT-350). Final Report on NCHRP Test 3-31. Midwest Roadside Safety Facility, Lincoln, Nebr., March 1998.

15.

Sicking

D. L.

, and Keller

E. A.

. Full-Scale Crash Evaluation of a Flared Energy Absorbing Terminal (FLEAT-350). MwRSF Research Report TRP-03-76-98. University of Nebraska, July 1998.

16.

Pfeiffer

B. G.

, Sicking

D. L.

, and Rohde

J. R.

. NCHRP Report 350 Compliance Testing of the BEST System. Final Report to Interstate Steel Company, Report TRP-03-63-96. Midwest Roadside Safety Facility, University of Nebraska-Lincoln, Dec. 1996.

17.

Mak

K. K.

, et al. Appendix K: Crash Testing and Evaluation of the MELT Terminal. Final Report. In Testing of State Roadside Safety Systems, Vol. 12, Texas Transportation Institute, Texas A&M Research Foundation, College Station, Dec. 1995.

18.

Mak

K. K.

, Ross

H. E.

Jr. , Bligh

R. P.

, and Menges

W. L.

. NCHRP Report 350 Testing of W-Beam Slotted-Rail Terminal. In Transportation Research Record 1599, TRB, National Research Council, Washington, D.C., 1997, pp. 22–31.

19.

Rohde

J. R.

, and Reid

J. D.

. Evaluation of the Performance Criteria for Wood Posts in Strong-Post W-Beam Guardrail. Presented at 76th Annual Meeting of the Transportation Research Board, Washington, D.C., 1997.