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Key Takeaways
- Automatic emergency braking requirements are moving forward, with a supplemental proposed rule expected from the FMCSA and NHTSA soon and compliance likely required for new heavy-duty trucks beginning in 2027.
- Side underride guard regulations remain under review, meaning no immediate action is required, but long-term trailer planning should account for potential future mandates.
- Early fleet planning reduces risk and costs, allowing truck owners and fleet managers to align equipment purchases, safety policies and budgets before regulations are finalized.
This year will be a pivotal planning period for the trucking industry as the Federal Motor Carrier Safety Administration (FMCSA) and the National Highway Traffic Safety Administration (NHTSA) continue advancing proposed safety regulations that could significantly impact heavy-duty trucking operations.
While these rules are not yet final, the federal regulatory agenda provides important insight into which initiatives are moving forward, which have stalled and how fleets should begin preparing now to avoid operational disruptions later. Two proposals in particular — rules regarding automatic emergency braking (AEB) systems and side underride guards — are shaping future equipment and safety strategies. At the same time, other anticipated regulations, such as mandatory speed limiters, have been withdrawn after strong industry opposition.
Understanding what is being proposed, what it means for fleets and how to prepare strategically can help fleet managers maintain compliance, protect drivers and control long-term costs.
What new safety rules are being proposed by the FMCSA and NHTSA?
Automatic Emergency Braking (AEB) Systems
One of the most significant proposed safety regulations is a joint FMCSA and NHTSA rule that would require automatic emergency braking systems on all new heavy-duty trucks. Originally expected to be finalized in early 2025, the rule is now scheduled to be reissued as a supplemental proposed rule sometime in early 2026, allowing for additional analysis and public comment before final adoption.
The proposal would mandate factory-installed AEB and electronic stability control (ESC) on new Class 7 and Class 8 trucks starting in 2027. Requirements for medium-duty vehicles are expected to follow in 2028. Once finalized, compliance would be mandatory for all newly manufactured vehicles within the affected weight classes.
Why This Rule Matters
AEB systems are designed to detect potential forward collisions and automatically apply braking if the driver does not react in time. These systems typically operate at speeds between 6 and 50 mph and are intended to reduce rear-end crashes caused by distraction or delayed reaction time. According to NHTSA estimates, widespread adoption of AEB systems could prevent thousands of crashes annually and save hundreds of lives.
Although many OEMs already offer AEB systems as standard or optional equipment, the final rule would eliminate any flexibility around installation. Fleets would also be prohibited from disabling these systems and would be responsible for maintaining them.
Side Underride Guards on Trailers
Another proposal under consideration by the NHTSA involves requiring side underride guards on trailers and semitrailers. These guards are designed to prevent passenger vehicles from sliding underneath trailers during side-impact crashes, which often result in severe injuries or fatalities.
The advance notice of proposed rulemaking for side underride guards closed in mid-2023. Since then, the proposal has remained in an “analyzing comments” phase. According to the most recent federal agenda, NHTSA expects to take further action on this rule in early 2026.
Why This Rule Matters
While no immediate compliance action is required, the extended timeline suggests the agency remains interested in advancing the rule. Fleets with long trailer replacement cycles or operations in dense urban or mixed-traffic environments should continue monitoring developments closely.
Speed Limiter Rule Withdrawn
In contrast to the proposals above, the FMCSA has withdrawn its proposed heavy-truck speed limiter rule. This rule would have required trucks with a gross vehicle weight rating over 26,000 pounds (Class 7 and 8) to be electronically governed between 68 and 70 mph.
Strong industry opposition citing high costs, enforcement challenges and limited safety data ultimately led to the rule being removed from the federal agenda. Recent legislation also restricts the use of federal funds to enforce speed limiter mandates on heavy-duty trucks.
As of now, there is no federal requirement for speed governors. However, many fleets already use them voluntarily as part of broader safety and fuel efficiency strategies.
What do these rules mean for fleets and truck owners?
Although none of these regulations are final yet, they carry meaningful implications for fleet planning, equipment acquisition and long-term budgeting.
For fleets purchasing new trucks in the next several years, AEB requirements are the most immediate concern. Once the AEB rule is finalized, all new Class 7 and 8 vehicles will need to meet federal standards. Fleets that delay planning may find themselves scrambling to adjust specifications, renegotiate orders or absorb higher upfront costs.
Trailer operators may face similar challenges if side underride guard requirements move forward. Retrofitting existing equipment could be costly and operationally complex, especially for fleets with large trailer inventories.
Even the withdrawal of the speed limiter rule carries strategic implications. While compliance is no longer mandatory, fleets that already use speed governance will need to maintain internal policies and documentation to support consistency and safety performance.
Ultimately, these proposals signal a broader shift toward technology-driven safety expectations. Fleets that adapt early will be better positioned to manage compliance and reduce risk.
What can fleets and truck owners do now to prepare?
Proactive planning is the most effective way to reduce disruption and costs when new safety regulations take effect. Fleet managers should consider the following steps as part of their 2026 readiness strategy.
Audit Fleet Inventory
Start by identifying which trucks and trailers are expected to remain in service beyond 2026. Understanding the age, specifications and upgrade potential of existing equipment helps prioritize replacement and retrofitting decisions.
Coordinate with OEMs Through Your Dealer
Work closely with your truck dealer and OEM partners to confirm that future vehicle orders align with anticipated AEB requirements. Clarifying which safety systems are included as standard equipment can prevent surprises later in the procurement process.
Update Internal Policies and Training
As technology becomes more integrated into vehicle safety systems, driver training and maintenance protocols must evolve. Fleets should begin aligning safety policies with emerging standards, including procedures for system inspections and fault reporting.
Budget for Phased Technology Upgrades
Rather than absorbing costs all at once, fleets can plan for phased investments that align with vehicle replacement cycles. This approach supports financial stability while maintaining compliance momentum.
Monitor Regulatory Developments
As these proposed rules prove, federal timelines and priorities can shift. Assigning responsibility for regulatory monitoring ensures your fleet stays informed and can adjust purchasing and policy decisions proactively.
Preparing Now Reduces Risk Later
While the FMCSA and NHTSA safety rules are still in the proposal stage, the federal agenda makes one thing clear: Expectations for heavy-truck safety systems are evolving. Fleets that wait for final rulings may face rushed decisions, higher costs and operational challenges.
Our trucking experts at Rush Truck Centers can help you position your fleet for a smoother transition when regulations take effect. We’re here to guide you through how these rules may impact your current operations and future purchasing decisions, ensuring every investment supports both compliance and long-term efficiency.
Early preparation not only strengthens safety performance and protects fleet investments, but it also provides peace of mind in a complex regulatory environment.
Contact your local Rush Truck Centers for help navigating these rules and understanding how they may impact your fleet planning.
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