FHWA Releases Results and Analysis of the Second Set of Crash Tests of ET-Plus Guardrail End Terminals |
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Federal Highway Administration
13 March 2015
FHWA 18-15
Friday, March 13, 2015
Contact: Neil Gaffney
Tel.: (202) 366-0660
WASHINGTON – The Federal Highway Administration (FHWA) today released its analysis of four crash tests recently conducted on the Trinity ET-Plus guardrail end terminal at a height of 31 inches. These four tests marked the end of eight planned tests required of Trinity Industries by the Federal Highway Administration.
The agency analyzed results of four crash tests conducted by the Southwest Research Institute's (SwRI) as well as findings reached by Dr. H. Clay Gabler, an independent expert tasked with reviewing the test results. Based on SwRI's results, Dr. Gabler's findings and FHWA's own analysis, FHWA concluded that the ET-Plus end terminal at the height of 31 inches meets the applicable crash test criteria followed by state DOTs.
"We're determined to protect travelers so we are leaving no stone unturned to determine the safety of these guardrails in question. The tests results we are sharing today are but one piece of our extensive review of the performance of this device," said FHWA Deputy Administrator Gregory Nadeau.
SwRI's results, the findings by Dr. Gabler and FHWA's complete analysis are available to the public on FHWA's website at https://www.fhwa.dot.gov/guardrailsafety/retesting.cfm.
Three of the four crash tests conducted by SwRI for the ET-Plus end terminal at a height of 31 inches were considered unremarkable. A fourth crash test resulted in damage to the exterior of the vehicle. FHWA worked with NHTSA to utilize data that enabled the comparison of hundreds of crashes with a comparable amount of door deformation at the same location on the door with the associated levels of injury.
In February, FHWA released results of four crash tests conducted by SwRI on the ET-Plus guardrail end terminal at the height of 27-¾ inches, along with an assessment by Dr. Gabler and the agency's own analysis and concluded the device at that height met the applicable crash test criteria.
The testing of the ET-Plus was the first step in FHWA's comprehensive plan to ensure the safety of roadside safety hardware and the ET-Plus. The results of the December 2014-January 2015 crash testing at Southwest Research Institute in Texas, along with the historical test data, show that the ET-Plus meets all applicable test criteria.
In December, 2014, FHWA commissioned a peer review of a study from the University of Alabama at Birmingham on "Relative Comparison of NCHRP 350 Accepted W-Beam Guardrail End Terminals." This report examined severe injury and death data involving five different guardrail end terminal designs and raised concerns about the ET-Plus. All four peer reviewers cited reasons to doubt assumptions made in the report, expressed concern about potential biases in the approach to selecting the crashes included or excluded from the analysis, and questioned the decision to consider only fatal and severe injury crashes. All four reviewers observed that the findings and conclusions are either questionable or invalid.
FHWA concurrently endeavored to collect measurements from more than 1000 ET-Plus devices from roadways to ensure that the devices tested in Texas were representative of those on the roads. A joint FHWA-AASHTO task force evaluated these measurements to reach two important conclusions:
FHWA's evaluation of the ET-Plus and of the process for assessing the safety of roadside safety hardware, however, is not concluded. A second joint FHWA-AASHTO task force is evaluating the crash data FHWA has collected to determine the in-service performance of the ET-Plus and whether the ET-Plus has vulnerabilities outside of the NCHRP 350 testing now being conducted. This includes analysis of:
FHWA, together with AASHTO, will objectively and thoroughly assess all of this information to reach a data-driven conclusion about the real-world performance of the ET-Plus and whether additional testing is needed.
"The crash test results we've received from Southwest Research Institute are one group of evidence we're using to answer the questions surrounding the ET-Plus," Nadeau added. "We will add them to the data we obtained from several other sources from around the country and continue to make informed decisions on the crashworthiness of the device."