Trinity Industries Inc.’s guardrail system will undergo additional crash testing by Virginia, raising new questions about a device on roadways across the country.

Some of Virginia’s six proposed tests on the ET-Plus, scheduled to begin in mid-September, will be different than those previously conducted for the U.S. government, according to documents reviewed by Bloomberg News.

Trinity said in a Thursday statement disclosing the tests that it does “not believe additional tests are needed.” In March, amid allegations the system was unsafe, the ET-Plus passed a series of eight crash tests overseen by the Federal Highway Administration, the government agency that helps regulate highway hardware.

Trinity has not yet seen a formal test plan from Virginia, Jeff Eller, a company spokesman, said in a phone interview. Tamara Rollison, a spokeswoman for Virginia’s transportation department, confirmed the new testing but declined to comment on details.

Two of the proposed tests involve a vehicle hitting the end of the ET-Plus at a shallow angle, according to the documents. Trinity’s rivals have said the system is most likely to malfunction when a car hits the end of it at such angles.

Shock Absorber

The ET-Plus is meant to act like a roadside shock absorber that blunts the ends of guardrails. More than 20 lawsuits allege that a modified version of the system locks up when hit, spearing through crashing cars instead of helping slow them down.

Last year, Virginia joined a whistle-blower lawsuit against Trinity alleging the company cheated taxpayers by failing to disclose changes it made to the system. The company sold thousands of unapproved and potentially dangerous highway guardrail devices to the state, according to the complaint.

Trinity is also appealing a $663 million federal fraud judgment against the company for its lack of disclosure of the ET-Plus changes.

“The ET-Plus system has been successfully crash tested more times than any product of its kind,” the Dallas-based company said in its statement.

–With assistance from Rachel Layne in Boston.