A complete substitute amendment, v2 significantly revises the scope and conditions for diesel engine emissions relief. It removes the findings section, introduces a new definition for "agricultural equipment," and alters the temperature thresholds and conditions for temporary derate suspension. Crucially, v2 expands permanent derate suspension to agricultural equipment and broadens the type of relief for Arctic regions, while also removing the explicit waiver of emissions compliance during these relief periods.
Cold Weather Diesel Reliability Act of 2026
- Sponsor
- Sen. Sullivan, Dan [R-AK]
- Committees
- Environment and Public Works Committee (primary)
- Last action
- Sep 16, 2026
Bottom line
The bill provides targeted regulatory relief for diesel engine emissions control systems in specific cold weather conditions and for agricultural use, aiming to prevent engine performance limitations that could compromise safety and operational reliability.
What it actually does
This bill requires the Environmental Protection Agency (EPA) to revise regulations to authorize diesel vehicle manufacturers to temporarily suspend engine derate or shutdown functions when ambient temperatures are at or below 20 degrees Fahrenheit. It also mandates the EPA to authorize permanent suspension of these functions for agricultural equipment and for covered vehicles primarily operated north of 59 degrees north latitude.
Proponents argue
Supporters argue that the bill enhances safety and operational reliability for diesel vehicles and equipment in extreme cold or agricultural settings where current emissions control systems can fail or be impractical. They contend that automatic engine shutdowns or power reductions in critical situations pose serious, life-threatening risks and that emissions safeguards were never intended to jeopardize human safety or impede critical mobility.
Opponents contend
Critics might argue that these exemptions, even if temporary or geographically limited, could lead to increased emissions of harmful pollutants, thereby undermining environmental protection goals and potentially contributing to air pollution. They may contend that technological solutions should be prioritized to ensure emissions compliance in all conditions rather than granting regulatory waivers.
The bill is short and relatively straightforward, allowing for a quick and comprehensive understanding of its provisions within the time typically allotted for legislative review.
Section 1
Short Title
This section establishes the official short title of the Act as the "Cold Weather Diesel Reliability Act of 2026." This provides a common and concise name for legislative reference and public discourse, making it easier to identify and discuss the bill's contents.
Supporters argue
A clear and concise short title helps in identifying and referring to the legislation, making it easier for the public and policymakers to discuss its purpose and implications.
Critics contend
No specific opposition is typically raised against the short title itself, though opposition to the bill's substance would implicitly extend to its title.
Tradeoffs
None inherent in the title itself, as it serves primarily as an identifier.
Section 2
Definitions
This section defines key terms used throughout the Act, including "Administrator" (referring to the EPA Administrator), "agricultural equipment" (nonroad diesel machinery for farming, excluding road vehicles), "covered manufacturer" (manufacturer of covered vehicles or engines), and "covered vehicle" (on-highway diesel vehicles or nonroad diesel equipment). These definitions clarify the scope and applicability of the bill's regulatory changes.
Section 3(a)
Temporary Cold Weather Derate Relief
This provision requires the EPA to authorize diesel vehicle manufacturers to temporarily suspend engine derate or shutdown functions that are triggered by emissions control system faults when ambient temperatures are at or below 20 degrees Fahrenheit. The engine must automatically return to normal emissions control operation once temperatures rise above 20 degrees Fahrenheit. This aims to prevent dangerous engine power reductions or shutdowns in cold conditions that could compromise safety or essential operations.
Section 3(b)
Permanent Derate Relief for Agriculture and Arctic Regions
This provision mandates the EPA to authorize manufacturers to permanently suspend engine derate or shutdown functions related to emissions control systems for two specific categories: agricultural equipment and covered vehicles primarily operated north of 59 degrees north latitude. This aims to address the unique challenges faced by these operators, such as the impracticality of diesel exhaust fluid systems in remote or agricultural settings, ensuring critical equipment can operate reliably.
Section 4
Rule of Construction (No Waiver of Emissions Standards)
This section clarifies that nothing in this Act waives compliance with any emissions standard under the Clean Air Act. This means that while the bill provides relief from engine derate or shutdown functions, it does not exempt vehicles from meeting the underlying emissions standards themselves, only from the enforcement mechanisms (derate/shutdown) in specific conditions.
The bill states that nothing in it waives compliance with any emissions standard under the Clean Air Act. This is a significant change from the original bill's language (in the 'DELETED' section), which explicitly waived compliance in the temporary cold-weather operational mode and for the diesel exhaust fluid system exemption.
Section 4, "Rule of Construction"
Why it matters:This is likely a legislative compromise to address concerns about environmental impact, making the bill more palatable by asserting that underlying emissions standards are not being abandoned, even if enforcement mechanisms are altered. It's standard legislative practice to include such clauses, but its specific wording here is crucial.
Case for: Supporters would argue this clause demonstrates the bill's commitment to environmental protection by ensuring that the underlying emissions standards of the Clean Air Act remain intact. It clarifies that the bill focuses on operational safety and practicality, not a rollback of environmental goals.
Case against: Critics might contend that while the *letter* of the law regarding emissions standards remains, the *spirit* and practical effect are undermined by suspending the primary enforcement mechanisms (derate/shutdown) in certain conditions. They could argue it creates a loophole where non-compliant vehicles can operate without immediate consequence.
Estimated impact: This clause significantly alters the environmental impact of the bill compared to its earlier version, potentially reducing the overall increase in emissions by maintaining the legal requirement for vehicles to meet standards, even if the immediate enforcement mechanism is suspended.