In highly regulated private industries the law means what it says ? right up until a regulator decides that it doesn’t. For that reason Uber, a company with a reputation for aggressively challenging legal norms, must have been particularly frustrated when the California Department of Motor Vehicles decided to publicly rebuke it for complying with the law of the Golden State.

The crux of the issue is that Uber decided to move forward with deploying some of its vehicles with automated technologies onto California’s roads without a permit which, the California DMV believes, it must first obtain before rolling out.

In a statement, the DMV said that it has a “permitting process in place” through which twenty manufacturers have obtained permits. Then, so as to leave no double about its position on the matter, stated that “Uber shall do the same.”

Now, whether the new Volvo XC90’s equipped with Uber’s technologies are “autonomous vehicles” as a matter of perception or regulatory projection is up for debate. Different people have different ideas about what fits that mold. But, when it comes to whether the DMV should take action to slow Uber’s work, the question turns from one of perception to one of law and textual interpretation.

California, by way of the DMV, has chosen to define an autonomous vehicle in regulation as a vehicle equipped with technology “…that has the capability of operating or driving the vehicle without the active physical control or monitoring of a natural person….” Thus, the factual question that confronted Uber before it made its decision to deploy the vehicles in California was simple: “is this vehicle capable of driving without being monitored or controlled by a driver?”

For all of their impressive capabilities, it is a matter of public record that Uber’s vehicles often require human intervention. By extension, those vehicles require constant monitoring by a human driver. On that basis, Uber likely thought that, while not toeing the industry line, its vehicles do not meet the definitional threshold necessary to trigger the state’s autonomous vehicle testing regulations.

Of course, what regulatory history there is that points to a different intent, one that tracks with the DMV’s argument, is no doubt informative and interesting as a matter of historical record, but it should not overcome the obvious strictures of the regulation as written.

In the meantime, the DMV has sent Uber a cease and desist letter. While the merits of regulation are often a matter of debate, the even application of the plain language of the law should not be. Unfortunately, it appears that Uber, by dint of its reputation, is facing unwanted “special treatment” by its regulator. Worse, the DMV may be expanding the reach of its regulations after the fact. If that’s the case, and certainty is lost, so too will be the very definitional purpose of the DMV’s regulations ? to make regular.

The National Highway Traffic Safety Administration earned plaudits from across the tech sphere for its recently released safety guidelines for self-driving cars.

With the NHTSA looking to offer guidance to this emerging industry, the agency issued a set of rules that largely just asks manufacturers to report on how they were following the guidelines. The 15-point checklist is vague in quite a few details, but that isn’t necessarily a tremendous problem so long as the standards remain voluntary, which they purport to be. To many, this approach struck a good overall balance between oversight and flexibility.

Regulatory ambiguity can, however, turn out to be a real nightmare with standards that are mandatory. Vague rules can leave even the best-intentioned firms at a loss as to how to proceed. Given how much of a premium consumer confidence will be in a market as revolutionary and potentially transformative as autonomous vehicles, it’s crucial that manufacturers comply with whatever standards the federal government promulgates.

That’s why it’s essential to pay close attention to an underappreciated part of the NHTSA guidelines — the opportunities they afford federal regulators to coordinate with the states on oversight that, in practice, will be anything but voluntary. Indeed, the early signs from the first of what will be many proposed state rules to follow in the wake of the NHTSA guidelines suggests that compulsory standards are exactly what we’re going to get.

First up are proposed rules from the California Department of Motor Vehicles, recently revised in response to the NHTSA guidelines. The revised draft of California’s model regulations is far more permissive than the original version the agency promulgated late last year, a set of changes that were celebrated by various observers, even me.

But delve closely into the updated DMV proposal, and you’ll find a requirement that manufacturers obtain a state permit certifying that any and all vehicle tests are conducted in accordance with the NHTSA?s “Vehicle Performance Guidance for Automated Vehicles.” Thus, in the nation’s largest testing jurisdiction, the NHTSA standards already are set to be made mandatory.

This is not to say the federal government doesn’t have a rule to play in oversight of self-driving cars. The feds are better situated to oversee the development of safety standards, and the door should be open to refine those standards. But coordinating with the states to turn those standards into a set of de facto binding obligations smacks of underground rule-making.

The California DMV might be complicit in this collusion, but it can’t be faulted for deferring to federal authority. Were the NHTSA?s safety standards clearer — an undertaking that presents risks and problems of its own — California?s approach wouldn’t actually be a problem. The fact that the federal guidelines are so vague in so many of the details means that we can’t really know either that manufacturers will be able to comply with California’s rules or that the state will be able to enforce them.

For now, state regulators should use their discretion to be as liberal as possible about what sorts of vehicle testing comports with the NHTSA safety guidelines. Over the longer term, what we need is for states like California to communicate to the NHTSA that it’s up to them to make absolutely clear what does and does not count as compliance.

It’s broadly understood how overly restrictive regulations can dampen innovation, but regulatory ambiguity can be just as bad. For regulators, the clock is ticking. It’s up to both the NHTSA and state agencies like the California DMV to bring the clarity this new market needs.