Sen. Amy Klobuchar is prodding the leadership of Uber and Lyft about the safety of their drivers using recalled vehicles.

Klobuchar, a Minnesota Democrat and 2020 White House hopeful, is leading a letter to the ride-sharing companies and is being joined by three senior Democratic members of the Committee on Commerce, Science and Transportation.

“Given that Congress has sought to improve the vehicle safety recall process, including by prohibiting companies from renting unrepaired recalled vehicles to consumers, we believe consumers should be similarly protected in the ride-sharing context and deserve to know when they are riding in a vehicle that has an unfixed safety recall,” the senators wrote.

Joining Klobuchar on the letter, released Thursday, are Maria Cantwell of Washington, Richard Blumenthal of Connecticut and Edward J. Markey of Massachusetts.

The letter comes in response to Consumer Reports study, released last month, which suggested vehicles used by Uber and Lyft drivers have a variety of recall-related issues, including potentially faulty airbags. Among the questions for the company CEOs is a request for a potentially massive data file on individual cars and trucks that have been subject to recall.

“Please provide a list of all such vehicles, their state of registration, and the recall that may be unaddressed,” the senators wrote. “Does your company have a periodic safety verification process that reviews whether vehicles are affected by a safety recall? If so, please provide the details of such process.”

There concerns appear to be focused on transparency, the idea that riders should know when there is a potential safety issue with a car.

“While we understand that both Uber and Lyft have taken steps to identify recalled vehicles and may waitlist certain vehicles that have been labeled as ‘Do Not Drive’ from the manufacturer or the National Highway Traffic Safety Administration (NHTSA), the onus primarily remains on drivers to ensure that open recalls are addressed,” the senators wrote.