A Texas federal judge handed down a $663 million judgment Tuesday against Trinity Industries, the guardrail maker accused of producing a faulty product that can jam and spear through vehicles.

The judgment stems from the trial held last year in a whistle-blower lawsuit filed by Josh Harman, a competitor who discovered in 2011 that Trinity had made a critical change to the dimensions of its ET-Plus guardrail in 2005, but failed to tell federal regulators as required by law.

The jury found the company liable for defrauding the Federal Highway Administration and awarded $175 million, which, under the False Claims Act, was tripled to $525 million. On Tuesday, the judge ordered Trinity to pay additional civil penalties of $138 million — amounting to $8,250 for each of 16,771 false certifications made to the government and other entities to get payment for guardrails. In addition, nearly $19 million in lawyers’ fees and expenses were awarded to Mr. Harman’s legal team.

Judge Rodney Gilstrap of United States District Court wrote that the plaintiffs had “introduced substantial evidence” showing that Trinity “made the decision to modify the ET-Plus, conceal such modifications, and falsely certify that the ET-Plus units had been accepted” by the highway agency.