The Research Gap They’re Trying to Fill

FMCSA acknowledges something remarkable in this filing: The agency has never actually studied whether its own warning device requirements work. The last serious research on the topic came from the Federal Highway Administration in the 1980s, and those studies produced “generally inconclusive or inconsistent results.” That was enough to convince NHTSA not to pursue its own research at the time.

Four decades later, the question suddenly demands an answer. The timing isn’t coincidental. Aurora is targeting commercial deployment of its autonomous trucks. Waymo continues expanding its driverless operations. And both have made clear that current breakdown procedures designed for human drivers don’t translate to vehicles without one.

The public comments FMCSA received during the initial 60-day notice period tell the story. Commenters raised concerns about “AV breakdown procedures,” the need for “redundant safety systems” in autonomous vehicles, and “the potential mismatch between other driver expectations and AV capabilities.” The industry sees exactly where this is heading.

What This Study Actually Accomplishes

This research gives FMCSA the evidentiary foundation to write new rules. If the study shows that warning triangles provide minimal safety benefit, a plausible outcome given the inconclusive historical research, the agency has justification to approve alternative compliance methods for autonomous vehicles. Electronic warning systems, vehicle-to-everything communication, enhanced exterior lighting: all become viable regulatory pathways once the agency can demonstrate the current requirements aren’t particularly effective anyway.

Conversely, if the study shows warning devices do meaningfully reduce crash risk, FMCSA has data to require autonomous vehicle developers to install automated deployment systems or equivalent technology. Either outcome clears the way for driverless CMV operations.

The filing notes that “alternative types of warning devices developed by industry, including those intended to increase driver safety during device deployment,” have prompted multiple exemption requests. Translation: Companies are already building solutions and awaiting regulatory approval to use them.

Warning device requirements are among several regulatory barriers to autonomous truck deployment, but they’re among the most concrete. Unlike debates over driver fatigue monitoring or hours-of-service compliance, which become philosophically murky when there’s no driver to monitor, the triangle requirement is binary. Either someone places them, or they don’t.

FMCSA’s decision to finally conduct this research signals the agency is serious about clearing the regulatory path for autonomous operations. The study results, expected to inform “future rulemaking related to warning devices,” will likely provide the foundation for either approving pending exemptions or establishing new performance standards for ADS-equipped vehicles.

For an industry watching Aurora and Waymo inch toward commercial deployment, this obscure paperwork-reduction notice is significant. The question of what happens when an autonomous truck breaks down on the shoulder of I-40 at 2 a.m. needs an answer. FMCSA is finally working on one.

Public comments on the information collection request are due 30 days from publication in the Federal Register.