In their report, the Federal Highway Administration and American Association of State Highway and Transportation Officials said they had found no evidence of multiple versions of the ET Plus end terminal on U.S. highways.
"Some folks are saying there's a third version of this device and it has different dimensions, so we went out and measured the dimensions on 1,000 ET Pluses," said Neil Gaffney with the highway administration.
"Turns out the dimensions are consistent and uniform."
Trinity's ET Plus — the end unit of the guardrail — is supposed to absorb impact and guide the rail so a crashing vehicle isn't slamming into the rigid steel end.
American authorities undertook to measuring along with a new round of crash tests amid allegations that Texas-based Trinity Industries had secretly changed the design about to save money, rendering them potentially lethal.
Last year, a Texas-based jury concluded Trinity had committed fraud in a civil action that could lead to US$700 million in penalties by providing incorrect information to U.S. road authorities.
Joshua Harman, the federal whistleblower who launched the successful fraud action, said the new report in fact proves — rather than debunks the idea — that there are two versions of the Trinity unit.
"It's just the federal government is trying to ignore it," Harman said. "They're trying to whitewash this to where nobody's responsible."
In Canada, several provinces stopped installing the ET Plus last fall and have been awaiting final crash-test results before deciding on further action.
In addition, the town of Stratford, Ont., launched a proposed $500-million class action against Trinity last month, alleging defects in the redesigned unit could cause guardrails to rip through cars and motorists instead of protecting them in crashes.
Stratford lawyer Matt Baer said the report appears to say the units on the road are in fact a "secretly modified version." In addition, he said, nothing in the report indicates the units are safe.
In a statement, Trinity said the task force report had validated its defence of its product.
"There is one version of the ET Plus extruder head (and) any claims to the contrary are purely false and misleading," the company said.
"The ET Plus is a robust end terminal system that performs as designed...when properly installed and maintained."
The task force also concluded the units put through crash testing in December and January are the same as those that are on the highways.
Final results of the tests have yet to be made public but are expected within the "coming weeks," Gaffney said.
At least 42 states have stopped installing the units while Virginia is pondering a product recall.
None of the provinces has reported any specific issues with the unit, but said they stopped installing them as a safety precaution and were awaiting the crash-test results before deciding on any further course of action.