The top U.S. highway safety regulator, Mark Rosekind, last month said of self-driving cars: “We are literally seeing the future being created in front of us.”

Uber Technologies and Ford Motor Co. this week proved Rosekind’s point. They announced plans to roll out autonomous vehicles and thus heightened a key question facing Rosekind and other regulators: What will be the rules of the road for these cars?

The short answer: It’s not clear yet.

Automakers currently do not need National Highway Traffic Safety Administration approval to roll out self-driving technology. They only have to attest that their vehicles meet federal safety standards. But there are no specific standards for autonomous vehicles or technology.

Regulations at the federal level — and in some cases, the state level, as in California — are still being ironed out even as automakers, ride-sharing services and technology firms march ahead with self-driving vehicles.

Uber, the popular ride-sharing service, said Thursday it will enable customers in Pittsburgh to get rides in Ford and Volvo autonomous vehicles, which will have human backup drivers, starting this month.

Ford also raised eyebrows Tuesday by saying it planned to produce fully self-driving vehicles with no steering wheels or pedals within the next five years.

They did so even as NHTSA, where Rosekind is the top administrator, is still developing a set of guidelines for self-driving cars.

That guidance is “being reviewed, tweaked and perfected,” Rosekind said in his July 20 speech, and it was thought the plans might have been ready by then.

But on May 7, the driver of a Tesla Motors’ Model S sedan was killed in a crash in Florida that occurred while he was using the electric car’s semi-autonomous Autopilot function.

NHTSA is investigating the accident and autonomous features on cars, and “the Tesla crash absolutely delayed the guidance” from federal regulators, said Jamie Court, president of the public advocacy group Consumer Watchdog.

The guidelines will be issued “soon,” NHTSA spokesman Bryan Thomas said via e-mail Thursday. They are expected to cover self-driving vehicles but also could include guidance for autonomous features such as Tesla’s Autopilot, which is designed to have a driver behind the wheel.

In response to the Uber announcement, NHTSA said it would “engage with all entities that are developing, testing and deploying automated technologies to ensure they are advancing road safety.”

Jack Nerad, executive editorial director at Kelley Blue Book, said self-driving technologies “might be coming too fast for the regulators to drink it all in.”

But he also noted that “the regulators have the power to control that speed” because ultimately a carmaker or ride-sharing service can’t place an illegal vehicle on the street.

The companies “have to continue to develop the technology, but you’re not going to put something in the marketplace that’s not going to be regulated,” Nerad said.

In April, NHTSA held public meetings at Stanford University and in Washington to get input on the guidelines for what it called “the safe deployment and operation of automated vehicle safety technologies.”

In announcing in July that traffic fatalities last year increased 7.7 percent to 35,200, NHTSA said it was “pressing forward” with the guidance to promote the development of the technologies because they “could greatly decrease the number of crashes.”

Some lawmakers have called for greater oversight of autonomous vehicles in light of high-profile auto-industry technology problems such as exploding Takata Corp. air bags and faulty ignition switches in General Motors Corp. vehicles.

“We have to have the technology right so that self-driving cars can live up to their promises,” Sen. Bill Nelson (D-Fla.) said during a Senate Commerce Committee hearing on autonomous vehicles in March.

Consumer Watchdog is concerned that the march toward self-driving cars is outpacing sufficient safety standards.

“What’s frightening is some of the carmakers want to rush the technology to the roads before we have a chance to create regulations to make sure they’re safe and before they accept legal responsibility if the technologies fail,” Court said.

In any case, Rosekind said in June that NHTSA would not block states from setting their own rules for self-driving cars, saying “what the states actually implement is their call.”

California’s Department of Motor Vehicles already has regulations governing the testing of self-driving cars on public roads, including that the vehicles must have a steering wheel and a human operator prepared to take over immediate control.

“I applaud the DMV because they’re basing their regulations on extensive testing that shows the robots aren’t ready to drive the cars without human beings taking over,” Court said.

The agency also is developing regulations covering the deployment of the cars on the road, and those rules are expected to be available for public review “in the next few months,” according to e-mail from DMV spokesman Jaime Garza.

But developers have chafed at the idea of having a patchwork of laws for using the cars nationwide. Nerad of Kelley Blue Book said that scenario would be “horribly difficult” for the industry as it tried “to adhere to potentially 50 different sets of regulations on autonomous vehicles.”