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Science Committee Ranking Members Request EPA IG Review Flawed Tennessee Tech Glider Truck Study

September 27, 2018
Press Release


(Washington, DC) – Yesterday, Ranking Member Eddie Bernice Johnson (D-TX), Ranking Member of the Environment Subcommittee, Congresswoman Suzanne Bonamici, (D-OR), Ranking Member of the Oversight Subcommittee, Congressman Donald S. Beyer, Jr. (D-VA) and Congressman Jerry McNerney (D-CA), wrote to the Inspector General (IG) of the Environmental Protection Agency (EPA) requesting that his office investigate a study on glider trucks conducted last year by Tennessee Technological University (TTU).


The Science Committee held a hearing on the glider truck issue earlier this month. The TTU study was funded by Fitzgerald Glider Kits, the largest producer of glider truck kits in the United States, and used by the EPA to help justify the Agency’s controversial decision to seek a repeal of the glider truck rule that has ensured the vast majority of these trucks complied with federal environmental regulations limiting toxic emissions from their engines.


“The proposed repeal of the glider rule is a serious and important issue that may impact the health and safety of the public in significant and harmful ways…By any objective assessment the testing measures used and the conclusions reached in the TTU study should warrant extreme scrutiny and skepticism,” the Members wrote in their letter.


Among the issues highlighted in the letter:


  •          The TTU glider study was not independent. It was funded by Fitzgerald Glider Kits, the largest producer of glider truck kits in the United States, and conducted at an unaccredited Fitzgerald facility.


  •          No credentialed scientist or engineer oversaw the glider study, and a first-year graduate student was in charge of analyzing the test data.


  •          The study failed to properly test for particulate matter (PM), a key toxic component of diesel engine emissions.


  •          The summary of the study falsified and omitted critical data, according to the study’s Principal Investigator, and the same flawed data was used by the EPA to help justify its repeal of the glider rule.


  •          The study’s Principal Investigator removed his name from the study and filed a scientific research misconduct complaint with Tennessee Tech because he felt the university misrepresented the test data and politicized the conclusions of the study.




Glider kits were traditionally used to help salvage the engines of damaged trucks and include the frame or chassis, front axle, and body/cab components. They become a glider truck when an engine, transmission, and rear axle are added. However, glider trucks normally use older engines that do not have modern-day emissions controls that help substantially limit toxic emissions from their engines. In 2016, the federal government helped to close this regulatory loophole by limiting the number of glider trucks each glider kit manufacturer could produce that escaped environmental regulations. They could still produce as many trucks as they wanted that complied with federal environmental regulations.


In November 2017, the EPA issued a proposed repeal of the glider truck rule that would have eliminated any environmental controls over the glider truck industry. As part of that proposed repeal, the EPA cited a June 2017 summary of a study from Tennessee Tech University (TTU) that concluded glider engines performed on par with or better than conventional engines. That study has come under extraordinary criticism from the university’s own faculty, as well as environmental experts as well as trucking industry officials, and sparked an internal investigation by the university. A February 2018 memorandum from the Interim Dean of TTU’s College of Engineering, for instance, said the glider study’s summary results included the “farfetched, scientifically implausible claim, that remanufactured truck engines met or exceeded the performance of modern, pollution-controlled engines with regards to emissions.” 


After the EPA used the study to help justify its repeal of the glider rule, the President of Tennessee Tech wrote to EPA and told them not to refer to the study in any way until the university’s internal scientific misconduct investigation was completed. The university has not publicly announced the status of this investigation, which, according to TTU’s own policy, should have been completed months ago.


A copy of the full letter can be found here.