NHTSA opened a docket on how aftermarket modifications knock ADAS out of calibration

The National Highway Traffic Safety Administration filed a notice of a public meeting on October 28 for publication in the Federal Register on October 29, under docket NHTSA-2026-1882. The agency will hold a workshop on aftermarket modifications and advanced driver assistance system performance on December 10, 2026, in the West Atrium of Department of Transportation headquarters in Washington.

The notice set out the agency’s reasoning. Cars have become software platforms that depend on dense sensor arrays, NHTSA wrote, and that dependence is what puts the modification trade in a new position: raising or lowering a vehicle, reshaping its bumper or body panels, or fitting wheels with a different offset can each move a sensor out of the alignment its software was tuned against. A system calibrated to the wrong geometry, the agency said, is worse at detecting the imminent crashes it was built for, and can fire when it should not.

The agency cast the workshop as a meeting point between the industry and its regulators, putting engineers, suppliers, modifiers and policymakers in one room to work through the engineering limits, what is happening in the field and what data would settle the question, and to look for ways of keeping safety-critical systems working without removing an owner’s freedom to alter the vehicle.

The workshop will be held in person and will not be live streamed, though a recording is to be published afterwards. Registration is free but required by December 3. The notice gives two comment deadlines that do not reconcile: 90 days following the meeting, which would close the docket on March 10, 2027, and April 19, 2027 in the comments section. The notice was issued by Cem Hatipoglu, associate administrator for vehicle safety research, under authority delegated in 49 CFR 1.95 and 501.8.