The Democratic senator, chairman of the Senate Subcommittee on Privacy, Technology and the Law, and former Saturday Night Live performer Al Franken has written to Uber’s chief executive asking for an explanation of the firm’s cavalier approach to privacy.

Franken laid out 10 questions for Uber, which this week has apologised for comments made by an executive suggesting he should dig dirt on a journalist; investigated another executive for accessing another journalist’s personal data; come under fire for tracking users’ one-night-stands in 2012; and has announced a partnership with Spotify.

The senator asks whether any disciplinary action was taken against Emil Michael, the executive who suggested hiring a team of reporters to research a hostile journalist, and how the firm plans to improve internal privacy training to ensure that employees follow the company’s policies.

He also asks what steps the firm is taking to limit access to its “god view”, which lets Uber employees track customers, and highlights the firm’s blogpost detailing users’ one-night-stands as an example of the company “condoning use of customers’ data for questionable purposes”.

“The reports suggest a troubling disregard for customers’ privacy, including the need to protect their sensitive geolocation data,” Franken writes. “Under what circumstances would an employee face discipline for a violation of Uber’s privacy policies? Have any disciplinary actions been taken on this basis?”

Franken has given Uber 28 days to respond to his questions, which were sent in his capacity as subcommittee chair. Uber says it will be responding to the Senator in the coming weeks, and has issued a statement in the meantime.

“Our business depends on the trust of the millions of riders and drivers who use Uber”, the statement reads. “The trip history of our riders is important information and we understand that we must treat it carefully and with respect, protecting it from unauthorized access.

“Ensuring that we have strong policies and practices in this fast-paced world of technology must be a constant quest. We have added Harriet Pearson, one of the most respected data privacy experts in the world and her colleagues at Hogan Lovells, to Uber’s privacy team. Hogan Lovells will conduct an in-depth review and assessment of our existing data privacy program and recommend any needed enhancements so that Uber can ensure that we are a leader in the area of privacy and data protection.

“We’ve learned a lot in four and a half years and want to continue to improve on the innovative tools that help us deliver on our mission of providing safe, reliable, affordable transportation to anyone, anywhere, at any time.”

Pressure on Uber chief executive Travis Kalanick is mounting from other sources. The influential technology author Robert Scoble has called on the executive to quit the firm, in order to “reboot the culture there and have Uber regain its loved status.”

“This company has deeply wounded itself,” Scoble continues. “The investors should insist that Travis go … This wound is a lot deeper than I thought and IS changing consumer behaviour. Travis, if I were you I would resign and help your company heal.”

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