NHTSA to hold workshop on how aftermarket modifications affect driver-assist systems
Changes to ride height, bumpers, body panels or wheel offset can throw off ADAS calibration, the agency says. The Dec. 10 session is in person in Washington. Registration closes Dec. 3.
The National Highway Traffic Safety Administration (NHTSA) will hold a workshop on Dec. 10, 2026 on how aftermarket modifications affect the performance of advanced driver assistance systems (ADAS). The notice ran in the Federal Register on Oct. 29 under docket NHTSA-2026-1882.
Why it matters
ADAS covers features such as forward collision warning and automatic emergency braking. They rely on cameras and sensors aimed at precise angles.
NHTSA says changes to ride height, bumper geometry, body panels or wheel offset can alter that calibration. Systems that are not calibrated correctly, the agency says, "are likely to have reduced performance in detecting the critical crash imminent situations they were designed for." They can also trigger false activations.
The notice says vehicle modification has long served customization, performance and "commercial utility." For fleets, that covers bumper swaps, lift or leveling changes and new body work, all common on work trucks and tractors.
What the workshop will cover
NHTSA says the event will bring together industry, technical experts and policymakers to look at:
- engineering parameters for modified vehicles
- field realities in shops and on the road
- data frameworks
- ways to keep ADAS and active safety systems working while still letting owners alter their vehicles
There will be time for questions after each panel. NHTSA also wants input on research needs, information gaps and next steps.
Key dates
| Item | Date | |---|---| | Registration deadline (free, required) | Dec. 3, 2026 | | Workshop, DOT headquarters, Washington | Dec. 10, 2026, 8 a.m. to 3:30 p.m. ET | | Comment deadline | April 19, 2027 |
The workshop is in person at the West Atrium of DOT headquarters, 1200 New Jersey Avenue SE. It will not be live streamed, but NHTSA will post a recording afterward. Updates and the agenda will be on the agency's event page.
Comments go to docket NHTSA-2026-1882 at regulations.gov.
For fleets
Nothing changes in the rules today. But shops that swap bumpers, change tires and wheels or adjust suspension on trucks with collision mitigation should watch this docket. How calibration after a modification gets handled is the question on the table.