No. Automatic emergency braking is still not required on heavy trucks. The federal rule proposed in 2023 was never finalized, and the agencies are now rewriting it. Electronic stability control is a different story. It has been required on truck tractors and certain large buses since 2015, and the stalled rule would extend it to smaller heavy vehicles.
This page tracks the status of the federal automatic emergency braking (AEB) and electronic stability control (ESC) rules for heavy trucks as of September, 2026.
Where the Rule Stands Right Now
In July 2023, National Highway Traffic Safety Administration and the Federal Motor Carrier Safety Administration (FMCSA) published a joint proposed rule that would have created a new Federal Motor Vehicle Safety Standard for automatic emergency braking (AEB) on vehicles weighing 10,001 pounds. The comment period closed in September 2023.
It never became a final rule.
A final rule was expected in early 2025. It did not arrive. The incoming administration decided the proposal needed a second look, and the two agencies chose to start over with a revised proposal rather than finish the old one.
The 2026 regulatory agenda, released in July 2026, lists a joint supplemental notice of proposed rulemaking. Land Line reported that the agencies were expected to issue it that same month. A supplemental proposal restarts the public comment process, which means a final rule is likely years away, not months.
Bottom line: as of September 2026 (or a motor carrier’s there is no federal requirement for automatic emergency braking on commercial trucks.
Electronic Stability Control Is Already Required on Some Trucks
This part gets reported incorrectly a lot.
The National Highway Traffic Safety Administration (NHTSA) issued FMVSS No. 136 in June 2015. That standard requires electronic stability control (ESC) on truck tractors and certain large buses with a gross vehicle weight rating over 26,000 pounds. Compliance began for typical three-axle truck tractors in August 2017.
So ESC is not a future requirement for the tractor pulling a loaded trailer down I-70. It has been mandatory equipment for years.
What the 2023 proposal would do is widen that standard to cover nearly all heavy vehicles weighing 10,001 pounds or more, which pulls in a large group of medium-duty trucks that are not covered today.
The distinction matters in a case. A rollover involving a late-model truck tractor may involve a system the truck was already legally required to have and to keep working.
What the 2023 Proposal Would Require
The proposal covered two systems working together:
- AEB on vehicles with a gross vehicle weight rating of 10,001 pounds or more, using radar and camera sensors to brake when a crash is imminent
- ESC extended to nearly all heavy vehicles at that same weight threshold, since stability control is what makes automatic braking behave predictably
- Federal Motor Carrier Safety Regulations requiring both systems to be switched on during operation
NHTSA estimated the combined rule would prevent 19,118 crashes, 8,814 injuries, and 155 deaths each year. The agency also pointed to roughly 60,000 rear-end crashes a year in which a heavy vehicle is the striking vehicle.
The proposal came out of petitions granted in 2015 to several safety groups, plus a mandate Congress wrote into the Infrastructure Investment and Jobs Act in 2021.
Why It Stalled
Three things slowed this down.
Reliability complaints. NHTSA opened an investigation in 2023 into reports that AEB systems on certain Freightliner Cascadia and Western Star 5700 trucks were braking with no obstacle present. In October 2025 the agency upgraded that investigation to an engineering analysis, a more serious stage that can lead to a recall. Investigators had reviewed 347 reports tied to 24 crashes, 13 injuries, and one death. That investigation is still open.
Driver opposition. A sudden, unrequested stop in a travel lane is its own hazard, and many drivers argued the technology was not ready to be required.
A broader shift on trucking rules. In July 2025, FMCSA and NHTSA formally withdrew the speed limiter proposal that had been pending since 2016. That withdrawal is a separate rule, but it signals the current posture toward new equipment mandates on trucks.
Worth noting for contrast: passenger vehicles did get a final AEB rule. FMVSS No. 127 requires automatic emergency braking on new cars and light trucks starting in 2029. Heavy vehicles have no equivalent date.
Timeline
| Date | What happened |
|---|---|
| June 2015 | NHTSA issues FMVSS No. 136, requiring ESC on truck tractors and certain large buses over 26,000 pounds |
| August 2017 | ESC compliance begins for typical three-axle truck tractors |
| November 2021 | Congress directs DOT to issue a heavy vehicle AEB standard in the Infrastructure Investment and Jobs Act |
| July 2023 | NHTSA and FMCSA publish the joint proposed rule for AEB and expanded ESC |
| September 2023 | Comment period closes |
| Early 2025 | A final rule is expected. It does not arrive |
| July 2025 | The separate speed limiter proposal is formally withdrawn |
| October 2025 | NHTSA upgrades its AEB false activation investigation to an engineering analysis |
| July 2026 | The 2026 regulatory agenda lists a new joint supplemental proposal |
| September 2026 | No federal AEB requirement is in effect for heavy trucks |
What This Means If a Truck Hit You
The absence of a federal mandate does not mean the technology is irrelevant to your case. In practice it comes up in four ways.
Many trucks already have it. Carriers have been buying AEB voluntarily for years, and it is standard on a lot of late-model tractors. The first question is not whether the law required it. It is whether the truck that hit you had it.
Some trucking companies don’t buy it. Truck manufacturers may offer AEB as either standard equipment or an option on new trucks. To save money or for other reasons some trucking companies may “deselect” AEB. So, even though the system is known to help avoid truck crashes, some motor carriers choose not to utilize this potentially lifesaving technology.
A system that was there and did not work is evidence. If the truck was equipped and the system was disabled, ignored, or left with dirty or misaligned sensors, that is an equipment failure and maintenance issue, regardless of whether a mandate existed.
ESC is already required on many tractors. If a rollover involved a truck tractor covered by FMVSS No. 136, and the stability control system was defective or switched off, that is a failure to meet an existing federal standard.
Industry practice can set the standard of care. What responsible carriers actually do is not limited to what a regulation forces them to do. Widespread voluntary adoption of a safety system may be something a jury is allowed to consider.
Proving any of this takes the truck’s electronic control module data, the fault and event records from the safety system, the maintenance file, and the manufacturer’s specifications for that model. Most of those records sit with the trucking company and are and can be easily lost if prompt steps are not taken to preserve it. Our page on how truck cases differ from car cases covers in more detail.
Talk to a Kansas City Truck Accident Lawyer
If you were hurt in a crash with a commercial truck, whether or not the truck had automatic braking, the evidence that may answer these questions In the possession the trucking company. It can be lost if steps are not taken promptly to preserve it.
Call Flick Truck Accident Law at (816) 221-0501 for a free consultation. There is no fee unless we win.
Frequently Asked Questions
Is automatic emergency braking required on semi trucks?
No. There is no federal requirement for automatic emergency braking on heavy trucks. NHTSA and FMCSA proposed one in July 2023, but it was never finalized, and the agencies are now preparing a revised proposal instead.
Is electronic stability control required on semi trucks?
Yes, on many of them. FMVSS No. 136 has required ESC on truck tractors and certain large buses over 26,000 pounds since 2015, with compliance beginning in 2017 for typical three-axle tractors. It is not yet required on all heavy vehicles weighing 10,001 pounds or more. That is what the stalled proposal would change.
When will the heavy truck AEB rule take effect?
There is no date. The rulemaking is back at the proposal stage, and a supplemental proposal restarts the comment period before any final rule can issue. The original proposal called for compliance three or four years after a final rule, so a realistic effective date is well beyond 2028.
Does a trucking company have to keep a voluntarily installed AEB system working?
No current federal rule specifically requires it, though the 2023 proposal would have added maintenance requirements. That does not make it harmless to neglect one. A carrier that disables a working safety system or lets sensors go unmaintained may still be held responsible under ordinary negligence principles.
Can I still bring a claim if the truck had no automatic braking?
Absolutely. Liability in a truck case rests on negligence, not on whether a particular piece of technology was installed. The absence of AEB does not excuse speeding, following too closely, driving past federal hours limits, poor maintenance or other negligent acts or omissions by the driver or trucking company.
This page was last reviewed and edited by Lawrence Flick on September 12, 2026.