The EPA is making changes to help truckers and farmers who have been stuck on the side of the road because of sudden diesel exhaust fluid (DEF) failures.
What’s new: On August 12, 2025, the EPA announced new guidance that tells truck and equipment makers to update software on existing DEF systems. This fix is aimed at stopping trucks from dropping to 5 mph or being forced to park due to DEF faults.
- The current DEF setup was meant to help control emissions, but instead, it’s left many diesel vehicles unable to finish a load, causing headaches and lost income for small businesses.
- With the update, drivers will get more time to fix DEF problems before their truck slows down or stops running.
Who’s backing it: Trucking groups like OOIDA thanked the EPA for listening, saying these new rules will help truckers safely manage DEF issues without being forced off the road. In the words of OOIDA’s Todd Spencer, it’s “commonsense” to let drivers get where they need to go and deal with repairs on their schedule.
Looking ahead: Starting with new trucks in model year 2027, manufacturers will have to make sure vehicles won’t lose power all at once from DEF issues. The agency says this should clear up much of the unnecessary downtime truckers have faced.
This change is expected to save family farms an estimated $727 million a year, according to the EPA.