Sponsors (2)
The bill trades clearer rules and fewer cold‑weather engine shutdowns for operators and remote communities (reducing safety and economic disruptions) against increased local emissions, enforcement complexity, and potential long‑term environmental and compliance costs.
Rural residents, truck drivers, and emergency responders in very cold areas face fewer engine shutdowns and reduced risk of being stranded because the bill allows/clarifies exceptions to forced derates or shutdowns in extreme cold.
Small-business owners, fleet operators, and manufacturers gain clearer regulatory expectations (defined terms and explicit cold-weather rules), improving predictability for vehicle design, certification, and day‑to‑day operations and reducing costly operational interruptions tied to DEF/emissions-system behavior.
Operators of vehicles primarily used in far-north areas (north of ~59°N) and supply chains in cold regions experience more reliable vehicle performance year‑round because impractical DEF requirements in sustained freezing can be avoided.
Residents and workers in cold regions could face higher local air pollution and increased respiratory health risks because exemptions or weakened enforcement allow diesel engines to run without full emissions controls in freezing conditions.
Creating cold‑weather carve-outs and special rules complicates enforcement and compliance, imposing administrative burdens and costs on federal, state, and local agencies tasked with oversight.
Allowing extended operation of vehicles with impaired emissions controls or slowing adoption of cleaner technologies may increase long‑term environmental harms and associated health and economic costs by delaying emissions reductions.
Based on analysis of 5 sections of legislative text.
Requires EPA to allow temporary engine derate/shutdown suspension at ≤0°C and to exempt certain cold‑region diesel vehicles from DEF system requirements, with EPA rules due in 180 days.
Introduced November 21, 2025 by Nicholas J. Begich · Last progress November 21, 2025
Requires the EPA to change Clean Air Act regulations so diesel vehicle manufacturers can temporarily suspend engine derate or shutdown functions when ambient temperatures are at or below 0°C, and to allow year‑round exemptions from diesel exhaust fluid (DEF) system requirements for diesel vehicles operated primarily in very cold conditions or north of 59° N. EPA must issue those regulatory revisions within 180 days; the law preserves all other emissions standards except these two narrow cold‑weather carve-outs.