Heavy-duty Truck “Glider Kit” Rule

The Environmental & Energy Law Program is tracking the environmental regulatory rollbacks of the Trump administration. Click here for the list of rules we are following. If you’re a reporter and would like to speak with an expert on this rule please email us

Why It Matters

More than 25% of the nation’s greenhouse gas emissions come from the transportation sector (chiefly cars and trucks), which also accounts for more than 70% of oil used in the United States. Medium- and heavy-duty vehicles cause about a quarter of the total transportation-related greenhouse gas emissions. A “glider” or “glider kit” is essentially an old heavy-duty truck engine installed into a new chassis, largely to avoid modern pollution control requirements. Many of the engines used in gliders generate, for example, nitrogen oxides (NOx) and particulate matter (PM) emissions that are 20 to 40 times higher than new engines. In fact, EPA estimated when it proposed new rules addressing gliders, that gliders accounted for just 2% of sales of new heavy-duty trucks but up to one half of all NOx and PM emissions from new trucks.

EPA’s vehicle emissions standards change as engine technology improves. Before 2016, EPA regulated gliders on the basis of the engine manufacture year: they could be marketed as new but only subject to lower emissions standards for older engines rather than up-to-date pollution standards.

In 2016, EPA and the National Highway Transportation Safety Administration (NHTSA) issued joint comprehensive regulations limiting the greenhouse gas emissions and fuel consumption of medium- and heavy-duty trucks. The emissions regulations apply pollution control standards to gliders based on the year the entire truck was manufactured, not just the engine. Including gliders in the regulations largely eliminates the incentive to use these much dirtier engines in newly manufactured trucks. These regulations are projected to reduce greenhouse gas emissions by nearly 200 million metric tons by 2050, and to significantly reduce NOx and PM emissions as well.

Current Status

On July 6, 2018, the EPA confirmed that it would not enforce the annual cap of 300 gliders per manufacturer, at least through the end of 2019. EPA is considering formally delaying the annual 300 glider cap until December 2019. In the meantime, EPA will continue to work on the proposed repeal of the emissions requirements for gliders while the emissions requirements remain stayed by the D.C. Circuit Court of Appeals.

Click here learn more about the history of this rule and actions that have been taken on it by the Trump Administration.


Thank you to Harvard student Laura Bloomer, JD/MPP 2019 and William Neibling, Research Counsel and JD 2013, for their assistance with this rule.

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