You don’t often hear a libertarian praising a federal regulator when it starts offering “guidance” and “coordination” for some innovative industry. Well, here goes: The National Highway Traffic Safety Administration is preparing to get deeper into regulation of self-driving cars. And that’s great news.

Readers know I’m a sort of skeptical booster of self-driving cars. I think we will get there, eventually. And I’m certainly hoping it happens before I shuffle off this mortal coil. But I think it will take longer than the less skeptical boosters hope, and the road will be rockier than they are expecting.

The goal is to get to what experts call “Level 4 Automation,” a car that can truly pilot itself without driver intervention. No commercially available car even yet has Level 3 automation, where the driver can cede control and read a novel, ready to take over when the car moves into a tougher environment, such as an urban street.

“Self-driving” functionality in current cars is Level 2: The car does the work, but you have to have a hand on the wheel, ready to take over in a split second. Level 2 automation is not really a self-driving car, and from the driver’s perspective, sitting there staring at the road and waiting for something to happen is probably worse than just driving the car. Moreover, since people don’t actually pay as much attention as they’re supposed to when using these features, these systems will probably also cause some accidents, even as they prevent others.

There are some big challenges on the way:

Technology. We think computers are smarter than us, but what they actually are is ferociously single-minded. This makes it hard to deal with conditions a human handles easily — like snow that obscures lane markers, or an emergency detour sign.

Regulation. Regulators are by their very nature risk averse. Tragedies get laid at their door, while the main result of a success is someone else gets the credit for whatever great new thing the regulator didn’t prevent from happening.

Innovating in a heavily regulated area, such as the national highway system, is thus a bit of a challenge. This difficulty is compounded by the fact that state and local governments also like to get in on the action. To get self-driving cars on our roads, we need a comprehensive federal framework that encourages innovation.

Liability. Self-driving cars will probably prevent thousands of accidental deaths every year. You would think that this would mean liability costs would go down. However, in the overwhelming majority of accidents, the liability resides with the driver. That places sharp limits on how much a plaintiff can expect to recover, because most people do not have much in the way of assets in excess of the value of their liability insurance.

Suing Ford, on the other hand, is a very different matter. Ford has a lot of assets, and juries are not shy about giving them to sympathetic people who have had something terrible happen. Self-driving cars will move the liability for accidents from drivers to deep-pocketed companies, so even though the number of accidents will go down, the expected value of filing a lawsuit will go up.

Ideally, regulators will establish some sort of safe harbor for companies: Comply with these standards, and you will be deemed to be shielded from judgment. Even more ideally, we’d move toward a no-fault standard for self-driving car accidents.

As you can see, there’s a long way to go before you can climb behind the wheel of a car, say “Home, Jeeves,” and take a nap. The good news is, the NHTSA has announced an initiative to help streamline the process. The president’s 2017 budget proposes $4 billion for developing connected car systems, and that will certainly help. More important, however, is that the NHTSA is moving forward to offer more regulatory guidance.

That’s good news. There are too many human drivers still on the road, and too big a patchwork of state and local laws to handle. A federal agency with a clear vision needs to be at the helm.

The bad news comes in two pieces. First, we could still end up with state-by-state guidelines that are needlessly restrictive.

The other is that the word “liability” appears nowhere in the regulator’s announcement. That’s not surprising, really. The NHTSA is a safety regulator, not a court of law, so liability isn’t really in its purview; that’s the job of state lawmakers. But someone needs to get a handle on this problem, lest the lawyers prevent automakers from putting more highly automated cars on the road.