NEW YORK — By last month, state transportation officials in Missouri had seen enough, they said.
Federal officials had long insisted guardrails throughout the state were safe. But some guardrail heads had apparently malfunctioned, in essence acting as spears when cars hit them and injuring people instead of cushioning the blow, Missouri officials said.
Missouri banned further installation of the guardrail heads on Sept. 24. It joined Nevada, which prohibited further purchases in January, and was followed six days later by Massachusetts. Lawsuits say the guardrails were to blame for five deaths, and many more injuries, in at least 14 accidents nationwide.
The Federal Highway Administration continues to say the guardrails, found on highways in most every state, meet crash-test criteria. The Texas manufacturer, Trinity Industries, denies there is a problem.
But internal communications and documents from the highway administration show a senior engineer expressed reservations about the guardrails’ safety before he signed off on their continued use two years ago. At one point, officials drafted a letter asking the manufacturer to conduct more testing, but it was never sent, according to interviews and a review of documents by The New York Times.
“There does seem to be a valid question over the field performance,” the senior engineer, Nicholas Artimovich, wrote in an e-mail in February 2012, after an agency engineer in South Carolina raised questions. In a separate e-mail to an outside expert a month later, Artimovich wrote that it was “hard to ignore the fatal results.”
The federal agency continues to allow states to use federal funds to purchase and install the guardrail heads. Concerns over the guardrails are at the center of a federal lawsuit going to trial Monday in Marshall, Texas.
A spokesman for the Federal Highway Administration, Neil Gaffney, said the agency approved the guardrails in 2005, based on results of crash tests conducted by Trinity and a Texas A&M University laboratory. It again reviewed those tests and others in 2012 and was satisfied with them, Gaffney said.
The agency declined to make Artimovich available for an interview.
A spokesman said that “Trinity has a high degree of confidence in the performance and integrity of the ET-Plus system,” using the product name of the guardrails.
At the heart of the issue is a change to the guardrail that Trinity made in 2005. Trinity’s new design reduced the width of the steel channel behind the rail head from 5 inches to 4. Instead of sliding along the rail, helping it curl out of the way of the oncoming vehicle, the rail head can become jammed, some state officials say. In those cases, the long metal guardrail does not get pushed aside — instead, it can become a bayonet.
Design changes are supposed to be disclosed to the Federal Highway Administration. But when Trinity narrowed its guardrail head design it did not make any such disclosures.
Nevada stopped purchases of the ET-Plus in January, citing Trinity’s failure to disclose the change in 2005. Last month, Massachusetts and Missouri issued bans of their own.
Massachusetts cited a University of Alabama study that looked at the performance of guardrail heads in Missouri and Ohio.
“In both states,” the study said, “it was found that the ET-Plus placed motorists at a higher level of risk of both serious injury and fatality relative to its predecessor, the ET-2000.”