We came across this news item: "Tesla must prove Cybercab is legal to sell, NHTSA says", Yahoo Finance, 16 Sep 2026 NHTSA sent Tesla a 21-part special order: describe the process for how the Cybercab was (self-)certified, and explain how a car with no steering wheel and no pedals meets federal rules written on the assumption that a human is driving. Tesla has until 30 September to answer.

Why is there that assumption? Because they didn't apply for the Part 555 exemption, that allows cars that are "solely operated by an ADS" (automated driving system) an exemption from the rules, if the rules would be “unduly burdensome.” Twenty-one questions to establish which rules a car is subject to. So we thought, what would this look like on our side of the Atlantic? We answered the European version of that question in an afternoon. Here is the answer, and here is why it took an afternoon instead of a minute.

The Experiment

We wrote a requirements specification for a driverless car/taxi, just to put a stake in the ground. This used a requirements engineer's formalism, by naming the defined terms of the instruments that apply:

The dynamic driving task shall be performed in its entirety, on a sustained basis, by an Automated Driving System within the vehicle's declared operational design domain.

This is our document, not Tesla's. We've never seen a Tesla requirements specification, and we hope theirs is more complete than ours. But look closely at how it's written: each requirement names a defined term and the instrument that defines it. Requirements bind things, and here it's the defined term with a pointer doing the binding.

Missing You

Take the second requirement first, because it's the one with a subject the type-approval system already recognizes: steering equipment.

For vehicles in the EU, you start with the General Safety Regulation (EU 2019/2144). Article 4(5) lists several subject areas, including "vehicle chassis, braking, tyres and steering", and points at Annex II. Annex II maps each subject to a UN Regulation. Item C1, steering equipment, maps to UN Regulation No 79.

Which edition? Annex I answers that: the 03 series of amendments, from December 2018 (OJ L 318).

Now we need to consider the first requirement, because R79 can't say anything about our (lack of) steering control until it can describe the car the control is missing from. Ours is a car where the steering is performed by an automated driving system, for the whole journey, inside a declared operating domain. Those aren't decorative words; they're the terms that decide whether this regulation is talking about our vehicle at all.

So we searched for them in R79. "Automated driving system" occurs in that text zero times. "Dynamic driving task," zero. "Operational design domain," zero. The bare acronym ADS, zero.

Not "defined differently," just not there at all. The edition the General Safety Regulation routes you to has no concept of an automated driving system in it; it was written before ADS was on the radar.

We have a correctly-drafted requirement, referencing the correct instrument, pointing at a document section that does not have the concepts of our design. Not compliant. Not non-compliant. Just a regulation with no way to see the car.

Ch-ch-ch-changes.

As it happens, you are allowed to use a newer edition of R79. A note in Annex I says compliance with a series of amendments adopted after the one named "shall be accepted as an alternative". Nothing says you should do that, and, more importantly, nothing tells you that it could (hopefully!) change the answer.

Now back to the second requirement, the one that got us here, and it's worse, because its term exists in both editions.

UN R79 §2.3.1 defines "steering control". Here it is in the edition the GSR names:

the part of the steering equipment which controls its operation; it may be operated with or without direct intervention of the driver

And here it is in the 04 series, the following published edition, same regulation, same paragraph number:

the part of the steering equipment directly actuated by a driver which controls its operation, but which may also operate without direct intervention of the driver (e.g. due to action by an Advanced Driver Assistance Steering System or ADS)

They added "directly actuated by a driver".

Under the newer text, the requirement applies with and without a driver. Under the older text that the GSR points to, no driver is mentioned, so the ADS's own actuation path is arguably a "steering control," and our requirement reads as forbidding the car being able to steer at all.

Same pin-cite. Same paragraph. Two meanings. Nothing in the requirement, in the General Safety Regulation, or in any tool the engineer was using records which one was meant.

The authors of the 04 series also knew it wasn't finished. Its introduction says the text has been adapted to approve vehicles with an automated driving system "where those vehicles are also equipped with manual driving controls", and that "in a second step, the Regulation will be further adapted to allow for the approval of automated vehicles which do not have manual steering controls..."

That sentence is about our car. (Yay!) It's just not in the edition we were sent to. (Boo!)

The 04 series does one more thing our car cares about. In the 03 series, the list of things the regulation doesn't apply to stops at paragraph 1.2.3. The 04 adds paragraph 1.2.4, under the heading "This Regulation does not apply to":

Vehicles of Categories M and N which are not equipped with manual steering controls intended for use during normal operation.

So in the 04 series, our car doesn't fail the steering regulation. It's just out of scope. It's a space where the rule hasn't been written. And just like "out of scope" is not "not compliant," it is very much not "compliant." Two editions, one with revisions that look like they apply, and our two-regulation car is still out of scope.

You Can Sleep While I Drive

So, while writing this up, we went looking for whether that follow-up to 04 had been released.

It has, and it changes everything.

The proposal sits on the World Forum's June 2026 agenda as ECE/TRANS/WP.29/2026/9/Rev.1 — the 05 series of amendments to R79. We found a draft from the task force's April 2025 text. Here is what it does to the scope:

Paragraph 1.2.4., delete: …

That's the paragraph that scoped our car out of the regulation. The 05 series deletes it, and says why: the exclusion "is no longer needed, as this proposal expands the scope to include ADS vehicles both with and without manual driving capability."

Follow that one paragraph across the three editions. In the 03 series, the one we got from the General Safety Regulation, §1.2.4 doesn't exist; the list stops at §1.2.3. In the 04 series it exists, and it puts our car outside the regulation. In the 05 series it's deleted, and our car is back in scope.

Absent. Excluding. Gone.

And watch what the amendment does to the regulation's account of itself. That sentence that promised a second step? It got edited:

In a second step, the Regulation ~~will be~~ has been further adapted to allow for the approval of automated vehicles which do not have manual steering controls…

That's some honesty.

This is what definitions look like when they move.

The Point Of It All

Here's what answering one requirement actually looked like. 

Four hops out of the document you started in, into a different legal corpus, landing on an edition that doesn't contain your vocabulary, while a term that does survive the trip arrives meaning something else, and the branch you finally settle on is already being amended out from under you.

The General Safety Regulation is not a rulebook. It's a routing table. Ask a language model what the rules for a driverless car are, and it will answer from whichever document it was shown, fluently, with no way of knowing that the term in your requirement isn't defined in that document, and might mean something else in a document it wasn't shown.

That's not a reading problem. It's a graph problem, and graphs are a machine's job: follow the reference, pin the edition actually cited, resolve every defined term against that edition, and shout when the term isn't there, or when it is, and it has changed.

Method. The specification is ours and it's synthetic, very much not a Tesla document, and very much not derived from one. There is no EU proceeding: NHTSA's order is a US matter, and we transposed the engineering decisions to the EU regime deliberately, because the EU's structure makes the point more sharply. EU texts were read from the primary sources below, retrieved by CELEX identifier on 16 September 2026.

On the 05 series, we went and checked. The World Forum adopted it at its 199th session in June 2026, by 36 votes to nothing, as ECE/TRANS/WP.29/2026/9/Rev.1. It says "Paragraph 1.2.4., shall be deleted:" The deletion quoted above is in the text that was actually voted on, not only in the earlier task-force proposal it came from. The sentence about the second step is there too, and by then it has stopped promising and started reporting: "the Regulation has been further adapted."

What has not happened yet is entry into force. A UN Regulation amendment adopted in June takes effect after a notification period, and the EU-facing consolidated text arrives later again — the 04 series reached the Official Journal as 2025/3. So the edition your citation resolves to today is still the 03 series, and it will keep resolving there for a while after the rule has changed.