MASH TL-3 Development and Evaluation of the Thrie-Beam Bullnose Attenuator

Robert Bielenberg, Ron Faller, Cody Stolle

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The thrie-beam bullnose system is a non-gating, redirective crash cushion that provides a safe, cost effective, non-proprietary option for shielding median piers and other median hazards. It consists of a guardrail envelope comprised of thrie-beam panels mounted at a height of 803 mm and supported by breakaway steel posts. The nose rail section and the first two adjacent rail sections are radiused and slotted, and the fourth and fifth rail sections are slotted. The combination of the radiused and slotted rail segments along with the breakaway posts allow the system to safely capture and decelerate vehicles impacting near the end or nose of the system, while redirecting vehicles impacting along the side. The barrier system was originally developed and evaluated under National Cooperative Highway Research Program (NCHRP) Report 350. In 2009, the American Association of State Highway and Transportation Officials (AASHTO) implemented an updated standard for the evaluation of roadside hardware. The new standard, the Manual for Assessing Safety Hardware (MASH), improved the criteria for evaluating roadside hardware beyond the previous NCHRP Report 350 standard through updates to test vehicles, test matrices, and impact conditions. A research effort was undertaken to evaluate the thrie-beam bullnose to MASH Test Level 3 through full-scale crash testing and modify the design as needed to meet the revised safety criteria. This paper details the evaluation of the thrie-beam bullnose through MASH TL-3 full-scale crash tests, modification of the original design to meet MASH criteria, and recommendations for implementation of the system.

Original languageEnglish (US)
Title of host publicationAdvances in Road Infrastructure and Mobility - Proceedings of the 18th International Road Federation World Meeting and Exhibition, 2021
EditorsAmin Akhnoukh, Kamil Kaloush, Magid Elabyad, Brendan Halleman, Nihal Erian, Samuel Enmon II, Cherylyn Henry
PublisherSpringer Science and Business Media B.V.
Number of pages17
ISBN (Print)9783030798000
StatePublished - 2022
Event18th International Road Federation World Meeting and Exhibition, 2021 - Dubai, United Arab Emirates
Duration: Nov 7 2021Nov 10 2021

Publication series

NameSustainable Civil Infrastructures
ISSN (Print)2366-3405
ISSN (Electronic)2366-3413


Conference18th International Road Federation World Meeting and Exhibition, 2021
Country/TerritoryUnited Arab Emirates


  • Breakaway posts
  • Bullnose
  • Compliance test
  • Crash test
  • Highway safety
  • MASH 2016
  • Roadside appurtenances
  • Thrie beam

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Computational Mechanics
  • Geotechnical Engineering and Engineering Geology
  • Environmental Engineering


Dive into the research topics of 'MASH TL-3 Development and Evaluation of the Thrie-Beam Bullnose Attenuator'. Together they form a unique fingerprint.

Cite this