Report Result

TRP-03-439b-25

Scott Rosenbaugh, Ryan Bickhaus, Ronald Faller, Jennifer Rasmussen (Schmidt), Bob Bielenberg, John Reid

2025-05-16

Approach guardrail transitions (AGTs) are used to safely connect guardrail to rigid parapets, such as bridge rails. Ideally, AGTs are installed tangent to the roadway and the bridge rail. However, there was a desire to install AGTs flared away from the roadway to satisfy geometry constraints or to shorten system lengths. Phase I of this study used LS-DYNA simulation to explore the performance of AGTs flared away from the roadway. Ultimately, a 15:1 flare rate was identified as the critical maximum flare rate for AGTs that would remain crashworthy. Phase II of this project consisted of full-scale crash testing in accordance with Test Level 3 (TL-3) criteria of the American Association of State and Highway and Transportation Officials’ (AASHTO) Manual for Assessing Safety Hardware (MASH). In test no. FLAGT-1, the 2270P vehicle impacted the system at an angle 25.4 degrees relative to the roadway and a speed of 63.3 mph. The 2270P pickup truck was contained and redirected by the flared AGT. However, the vehicle snagged on the system at the upstream edge of the concrete buttress, which resulted in excessive occupant compartment deformations to the toe pan and wheel well, as well as an excessive longitudinal acceleration of -24.2 g’s. Thus, test no. FLAGT-1 failed to satisfy the safety performance criteria of MASH test designation no. 3-11.

Highway Safety, Crash Test, Roadside Appurtenances, Compliance Test, MASH 2016, Test Level 3, Approach Guardrail Transition, AGT, Flare, Flared Guardrail

TRP-03-439b-25.pdf