Truck Drivers Expose Flaws in EPA Emissions Fix
The Environmental Protection Agency is reviewing more than 13,500 public comments on a proposal that would change how diesel trucks respond to diesel exhaust fluid (DEF) and emissions-system problems. The agency’s decision could replace federally required engine derates with audible and visible warnings on newly manufactured diesel vehicles and equipment.
Proposal Would Replace DEF-Related Derates
Under current emissions controls, certain unresolved problems involving DEF levels, sensors or other pollution-control components can eventually trigger an engine derate. The reduced-power mode may limit a truck’s speed and performance until the issue is corrected.
The proposed changes would require visible and audible warnings instead of federally mandated DEF-related derates. The Owner-Operator Independent Drivers Association said an audible warning system could give drivers more time to address DEF problems safely without drastically reducing speed, missing deliveries or taking a truck out of service for an extended period.
The proposal would apply to newly manufactured diesel vehicles and equipment, including work trucks such as tractor-trailers and dump trucks.
Industry Groups Support More Flexibility
OOIDA said the proposal could provide relief for drivers dealing with emissions-system problems. However, the group also warned that other provisions could create significant costs for truck owners and operators.
The National Association of Convenience Stores said DEF is widely available, with more than 100,000 retail locations offering the fluid across North America. The group said more than 95% of North American truck stops sell DEF and argued that existing EPA guidance should be implemented before additional changes are made.
NACS Deputy General Counsel Matt Durand said changes that make DEF appear optional could reduce drivers’ willingness to purchase and use it, potentially undermining the emissions benefits of modern diesel engine systems.
Warranty and Compliance Provisions Draw Criticism
The proposal also would establish non-conformance penalties, allowing manufacturers to pay penalties for failing to meet certain emissions requirements. In addition, the EPA has proposed shortening emissions warranty periods and delaying stricter “useful life” requirements, which determine how long engines and vehicles must continue meeting pollution standards.
Environmental groups have criticized those provisions, saying they could result in greater air pollution. The groups pointed to the EPA’s own analysis, which they said showed that removing or reducing DEF-related inducements could increase harmful emissions, particularly in communities near major highways and freight corridors.
EPA Review Still Ahead
The comment period has closed, leaving the EPA to review the submissions before deciding whether to issue a final rule. The proposal would provide additional flexibility around DEF-related derates while retaining the underlying EPA27 emissions requirements.
Paccar Senior Director of Powertrain Planning Carl Hergart said the EPA27 standard remains a major technological challenge despite the proposed flexibility. He cited a nitrogen oxide limit of 0.035 grams per horsepower-hour, representing more than an 80% reduction from the current standard.
No final decision or implementation timeline was included in the available information.
