Video from the eighth crash test of a Trinity guardrail, which shows a Geo Metro spinning out after hitting the guardrail, causing the driver’s door to strike a bent piece of metal.  WASHINGTON — A potentially dangerous guardrail cleared a crucial hurdle on Friday when federal officials released their analysis of four crash tests and gave the product passing grades, even for the final test, in which the driver’s door was severely damaged.  But the findings, by the Federal Highway Administration, seemed only to intensify the debate over the guardrail, called the ET-Plus, as critics on Capitol Hill denounced the conclusion as being the result of a flawed process. The guardrails, made by Trinity Industries of Dallas, are suspected of jamming when hit head-on, causing the metal rail to spear into the passenger compartment.  The agency defended its analysis and testing methods. It said it would continue to research the issue.  The results released on Friday covered the final four of eight tests.  The crash tests began in December after a federal jury in October found Trinity liable for defrauding the Federal Highway Administration because it had not disclosed design changes it made in 2005. Though that case, a whistle-blower lawsuit, was filed on the agency’s behalf, the Federal Highway Administration chose not to participate in it.  A crucial point of interest in Friday’s analysis focused on the eighth and final test, conducted in late January. A 1998 Geo Metro traveling about 60 miles an hour was driven into an ET-Plus guardrail and spun out, causing the driver’s door to strike a bent piece of the metal guardrail and collapse inward.  The agency said its measurements showed that the driver’s door was pushed in only 6.75 inches and it did not believe that the damage was likely to cause serious injury.  “We concluded that the ET-Plus meets the applicable crash test criteria,” said the agency’s deputy administrator, Gregory G. Nadeau.  But George Carpinello, a lawyer representing Joshua Harman, the whistle-blower who prevailed in the federal lawsuit in October, said that the agency ignored its own guidelines. In 2003, the National Highway Traffic Safety Administration published a study at the request of the Federal Highway Administration saying that the threshold for such damage had been set at six inches, Mr. Carpinello said. It also said that when there were intrusions of six inches or more in the crashes it analyzed, 36 percent of injuries were of moderate to maximum severity.  A spokesman for the National Highway Traffic Safety Administration, Gordon Trowbridge, said the agency needed more time to respond to questions about whether the guideline stated in the 2003 study was relevant to the recent Trinity crash tests and, if so, whether it was considered. “While it is not physically possible to provide information we are confident is accurate on such a short deadline, we will respond in full as soon as we have all the facts,” he said.  The Federal Highway Administration did not immediately comment, citing the short deadline.  Senator Richard Blumenthal, a Democrat from Connecticut, denounced the agency’s analysis of the Trinity crashes, saying in a statement that the agency had “given the ET-Plus a passing grade after allowing the manufacturer to conduct sham tests rife with flaws.” For example, he said he believed that the agency had used older, less rigorous testing standards.  Tony Furst, the agency’s associate administrator for safety, said he believed the guardrails would have passed the test with the newer standards.  Mr. Nadeau repeatedly said that the federal investigation into the ET-Plus would continue, and he said that the crash tests meant the agency had only “completed the first step.” Further steps involving data collection and a performance review of ET-Plus units in the field could last several more months or longer.  The New York Times has exposed missteps and delays by automakers and federal safety regulators in responding to deadly defects in automobiles during what has become a record year for recalls.  But that leaves states, many of which temporarily banned the ET-Plus while waiting for guidance from the federal agency, with no clear path in the meantime.  Mr. Nadeau said the guardrails remained eligible for federal reimbursement if the states bought them — a crucial endorsement for state transportation departments. But ultimately, he said, “each state will make that determination.”  Some states are not taking any chances. Virginia, which banned the guardrails in October, is moving forward with a plan potentially to remove ET-Plus systems from its roads and said it was already replacing damaged ET-Plus units with non-Trinity products.  Marshall Herman, a spokeswoman for Virginia’s Department of Transportation, said on Friday that the state “still has ET-Plus replacement contracts out for bid” and that it would review all data from the eight crash tests before making its own determination of the results, which could take several weeks.  Jeff Eller, a spokesman for Trinity, said that the company would analyze Friday’s findings and that a decision about whether to resume sales and shipments of the product “will be forthcoming.”  Criticism from Capitol Hill about the agency’s handling of the ET-Plus investigation has mounted recently. This month, Mr. Blumenthal and other Democratic senators requested that the Government Accountability Office conduct a formal investigation into the Federal Highway Administration because of a “continuation of troubling developments” regarding its evaluation of the ET-Plus.  Mr. Nadeau emphasized on Friday that the agency had been investigating the guardrails since 2012. But until recently, the agency had defended the guardrail units for more than two years, even after it learned that Trinity had not disclosed the design change in 2005. At one point in 2012, agency officials drafted a letter asking the manufacturer to conduct additional testing, but the letter was never sent.  Mr. Harman brought the whistle-blower suit in 2012 after discovering that the company made design changes to its guardrails in 2005 but did not tell the Federal Highway Administration for seven years, despite requirements that such changes be reported immediately.  Though the verdict dealt with fraud against the government, the trial offered a public airing of safety concerns about the guardrails. Mr. Harman told the highway agency of the unreported changes in early 2012. Since then, Trinity has mounted an increasingly aggressive lobbying campaign of state attorneys general and has become one of the nation’s top donors to attorney general political causes.  Despite that effort, in December, Virginia’s attorney general, Mark R. Herring, became the first state attorney general to file a legal action against Trinity.  Aaron M. Kessler reported from Washington and Danielle Ivory from New York.  A version of this article appears in print on March 14, 2015, on page B1 of the New York edition with the headline: Guardrails Said to Pass Safety Tests . Order Reprints| Today's Paper|Subscribe
Critics questioned the testing standards and pointed to the one test in which a bent piece of rail pushed a driver’s door in 6.75 inches.