[5] A lawsuit under the False Claims Act filed in 2012 against Trinity stated that these changes were causing damages to cars and drivers.

[6] In 1993, National Cooperative Highway Research Program published a report titled NCHRP Report 350, outlining an updated crash test and evaluation requirements to reflects the higher speeds and types of larger vehicles on the United States highways.

In 2005, Trinity proposed that it would use the 4-inch channel version for a new set of tests required for the new 31-inch (79 cm) guardrail height installations per NCHRP Report 350.

[8] On March 6, 2012, Joshua Harman, a Virginia guardrail engineer and a co-owner of a Trinity's competitor, was whistleblower in a federal suit which accused Trinity of failing to notify the Federal Highway Administration (FHWA) of a change of size of the end piece from five to four inches.

[4][11] A federal jury found Trinity guilty of fraud by not reporting a change of one inch made to the ET-Plus end terminal.

[12] In October 2013, there was an allegation that Trinity produced the third version which slightly changed the 4-inch model was installed in Alabama highways in April 2013.

It was alleged that the third version had some minor dimension changes including an expansion of welded-steel unit by 0.25 inches (0.64 cm), and those would be enough to prevent the 4-inch ET-Plus to malfunction.

[13] In November 2014, Trinity announced its plan to retest the 4-inch ET-Plus model and stopped the sale of the units until testing is completed.

[4] In December 2014, an FHWA commissioned peer review of the study "Relative Comparison on NCHRT 350 Accepted W-Beam Guardrail End Terminals" was conducted by the University of Alabama at Birmingham.

The result published on March 11, 2015 concluded that there was no systematic variation in the dimensions of the 4-inch ET-Plus units on the roadways and the ones used in the Southwest Research Institute tests.

[19] In June 2015, a US district court jury verdict of $663 million was passed against Trinity Industries for defrauding the Federal Highway Administration.