Uber and Lyft decided to skip a congressional hearing Wednesday aimed at examining their safety and labor practices, to the aggravation of members of the committee who are threatening to press ahead regardless with new legislation.

The two companies have come under increased scrutiny in recent months over their treatment of drivers and their efforts to keep passengers safe, prompting a House Transportation subcommittee to call a hearing and urge the companies to testify on the future of ride-hailing.

Both Uber and Lyft decided not to send representatives, however.

That prompted Transportation Committee Chairman Peter A. DeFazio (D-Ore.) to say during the hearing Wednesday that the panel will press ahead with legislation that could encompass safety and labor for transportation network companies, or ride-hailing companies, with or without their cooperation.

“The failure today of Uber and Lyft to appear is a telling sign that they don’t want to answer questions on the record about their operations,” DeFazio said at the hearing. He said they might be trying to avoid talking about safety problems or their labor records.

“For their long-term survival, for any hope of ever partnering with agencies who utilize Federal funds, they are going to have to clean up their acts,” he added.

The refusal by Uber and Lyft to appear to testify is the latest wrinkle in a long-running, rocky relationship between Silicon Valley tech companies and lawmakers in the nation’s capital. Many in tech think that their companies are trying to improve the world, despite problems that may surface along the way. They contend that the government should stay out of regulating what they think is important innovation.

Just last week, Facebook chief executive Mark Zuckerberg agreed to testify on the social media giant’s plans to launch a cryptocurrency, Libra, after lawmakers pressured him to do so. Previously, Chief Operating Officer Sheryl Sandberg planned to testify.

Lawmakers’ attention has been drawn to Uber and Lyft after reports about the companies’ safety practices and treatment of drivers.

Last month, The Washington Post reported that employees in Uber’s special investigations unit said they were under pressure to put the company’s interests over the safety of passengers. Uber has said the unit’s role is to “provide specialized customer support to riders and drivers dealing with very serious real-life situations.” In August, The Post reported on what victims said were inadequate responses to sexual harassment and other types of misconduct on the Lyft app. Lyft vowed to make safety changes in the wake of that report and other scrutiny.

Uber said it had been in talks with the committee since officials reached out to the company on Sept. 27, but did not specify why it didn’t testify. The company said it has added more safety features in the past year than it had in the eight years prior.

“We share Congress’ focus on keeping Americans safe on rideshare,” company spokeswoman Susan Hendrick said.

Lyft said it has engaged with nearly all of the subcommittee’s 56 member offices in advance of the hearing and said the discussions were productive. It touted its safety practices, including driver criminal background checks, ongoing notification of violations and new features to verify drivers’ identification in real time.

“In communities across the country, Lyft provides economic opportunity for drivers, and affordable, reliable transportation for riders,” Lyft spokeswoman Campbell Matthews said. “We take this work extremely seriously and believe safety is fundamental to these efforts.”

Lawmakers delivered several rebukes to the companies amid their absence at the hearing, which instead featured testimony from labor and trade groups. The panel focused questions on safety and worker issues.

“Uber and Lyft have missed an important opportunity for them,” said Del. Eleanor Holmes Norton (D-D.C.), who chairs the highways and transit subcommittee and oversaw the hearing. “That will not stop this committee or this subcommittee from doing its duty.”

Reps. Christopher H. Smith (R-N.J.) and Thomas Suozzi (D-N.Y.) spoke about “Sami’s Law,” a bill they are sponsoring aimed at enhancing ride-hailing safety. The bill calls for measures like Uber and Lyft vehicles to require illuminated signs, front and rear license plates and scannable codes for passengers. (Uber recently announced it would implement optional pin-based ride verification for rides.)

Some Republicans, however, accused Democrats of acting with an agenda to prop up taxis and mass transit. “Let the people choose and the free market can provide,” Rep. Thomas Massie (R-Ky.) said in a tweet.

The committee’s ranking Republican, Rep. Rodney Davis (Ill.), avoided criticizing the companies themselves but emphasized safety.

“While we are all excited about the prospects for new, integrated mobility options, we must be cognizant of its risks and impacts, both for riders and drivers,” he said in his opening statement. “The safety of our traveling public is of paramount importance, and regardless if you’re traveling in a taxi, taking public transit, or riding through a [ride-hailing company], you need to feel safe.”