A study conducted by the U.S. Environmental Protection Agency’s Air Enforcement Division has revealed the full scope of aftermarket emission defeat devices used by diesel vehicle owners across the country.
In the report, the AED estimates that emissions controls have been removed from more than 550,000 diesel pickups in the last decade. The removal of these systems will produce more than 570,000 tons of excess oxides of nitrogen and 5,000 tons of excess particulate matter over the lifetime of these vehicles.
It’s important to note that the report relates specifically to class 2b and class 3 diesel pickups (those weighing between 8,501 lbs – 14,000 lbs) and not those that weigh less or more. All up, the AED says the 550,000 tampered trucks constitute approximately 15 per cent of the national population of diesel trucks that were originally certified with emissions controls systems. The excess nitrogen oxide produced by these trucks is the equivalent of adding more than 9 million additional diesel pickups to the U.S.’s roads.
While the Clean Air Act prohibits tampering with emissions controls, the EPA has found numerous companies and individuals manufacturing, selling, and installing hardware and software designed to defeat these controls. The most common way to defeat the controls are through simple software tunes that alter the engine’s software functions and calibrations. Many owners also fit straight-through exhaust systems, therefore removing the standard exhausts that feature aftertreatment systems.
The AED report also reveals that states without regular vehicle inspections have a higher percentage of diesel trucks with defeat devices. For example, as many as 18.6 per cent of North Dakota’s pickup truck fleet in 2016 is estimated to have defeat devices. Other states high up in the list include Idaho with 15 per cent, Wyoming with 14.2 per cent, Maine with 13.5 per cent, and Michigan with 13 per cent. At the bottom of the list is California with 1.8 per cent, hardly a surprise given its strict enforcement of emissions standards.