Citation

Reid JD. J. Transp. Saf. Secur. 2009; 1(1): 32-45.

Copyright

(Copyright © 2009, Southeastern Transportation Center, and Beijing Jiaotong University, Publisher Informa - Taylor and Francis Group)

DOI

10.1080/19439960902735212

PMID

unavailable

Abstract

The American Association of State Highway and Transportation Officials' Roadside Design Guide recommends that W-beam guardrails should not be placed on roadside slopes steeper than 10H:1V. With the development of the Midwest Guardrail System (MGS), the higher mounting height and deeper blockout may provide sufficiently improved performance to relax that recommendation. An LS-DYNA simulation study was conducted to determine that an 8:1 slope, with a barrier placement of 1.5 m down from the slope-break point, was the critical condition for determining the maximum allowable slope for the MGS. Subsequently, two full-scale vehicle crash tests were performed on the system according to Test Level 3 specified in the National Cooperative Highway Research Program Report (NCHRP) No. 350, Recommended Procedures for the Safety Performance Evaluation of Highway Features. The first test was with a pickup truck, impacting the system at a speed and angle of 100.4 km/h and 25.9 degrees, respectively. The second test was performed using a small car, impacting the system with a speed and angle of 99.6 km/h and 21.6 degrees, respectively. Both tests successfully passed all evaluation criteria. Therefore, the research has shown that the MGS may be placed anywhere on an 8:1 or shallower slope and meet NCHRP 350 safety recommendations.