Executives from Google, General Motors, Delphi, and Lyft appeared before a US Senate committee Tuesday to testify on their latest efforts to bring self-driving cars to the public. But when asked whether they support a bill to require anti-hacking safeguards in connected and autonomous cars, they stuttered through a series of non-answers. Their reticence isn't unusual — most corporate-minded individuals view the prospect of new government mandates with a certain queasiness. But the squirming on display in Congress today could hint at future conflicts down the road should lawmakers continue to pursue legal checks on new vehicle technology.

The questioning was led by Senator Edward Markey (D-MA), who is sponsoring a bill with Senator Richard Blumenthal (D-CT) to require the Federal Trade Commission and the National Highway Traffic Safety Administration to develop standards to protect drivers' privacy and prevent potentially deadly hacks. Markey went down the line, asking each of the executives to state "yes or no" whether they supported mandatory privacy and safety standards. And in response, he got a lot of deflection.

"We haven't determined whether we need mandatory standards or not," said Glen DeVos, vice president for global engineering at Delphi. "We think a more flexible approach is preferable," said Mike Abelson, vice president at GM. "Google is attacked on a regular basis," said that company's head of self-driving cars, Chris Urmson. "We have hundreds of people devoted to cybersecurity." Translation: Butt out, senator. (Urmson later clarified that he was "not in the position to comment for Google" on the question of uniform standards for the entire industry.)

Markey wasn't happy with those responses. "I understand what you're saying," he said. "Witnesses sat here 30 years ago and said the same thing about airbags and seat belts. How they should leave it to the individual companies, that it was hard to mandate a specific airbag and it would be very expensive. So I understand the consistency over the decades. At the same time, people expect airbags to protect their children. And they're going to expect certain standards across the board that are going to protect people."

In introducing his bill last year, Markey's office released a report that found nearly all cars on the market include wireless technology that could be vulnerable. During the hearing, he recalled a more personal incident when he was hit by a car at the age of five while chasing two other children into the road. "As we're moving forward, we just want to make sure that we don't have unnecessary accidents," the senator said.

Blumenthal also expressed his disappointment with the lack of support on the panel. "The credibility that this technology has may become exceedingly fragile if people can't trust standards that are uniform and mandatory," he said.

The senators did find one voice of support on the panel. Missy Cummings, director of Duke University's Human and Autonomy Lab, said she agreed there was the need for new rules in place to protect drivers, but doubts the federal government's ability to keep track of the companies that are creating this new technology. "It's happening so quickly that the government institutions cannot keep pace," she said.

But there is more at stake than whether Google and GM want to operate under a new set of government rules. Cummings underscored the point that lives were hanging in the balance. "There is no question that someone is going to die in this technology," Cummings added later in the hearing. "The question is when, and what can we do to minimize that."