In February, Senator Ed Markey (D-MA) sent inquiries to seven U.S. firms engaged in autonomous vehicle technology along with a set of questions. He particularly sought to understand how frequently these firms’ vehicles — operated by Aurora, May Mobility, Motional, Nuro, Tesla, Waymo, and Zoox — depend on feedback from remote personnel. According to the outcomes of Markey’s investigation released on Tuesday, they all declined to provide answers.

The data published by Markey’s office exemplifies the reluctance of autonomous vehicle companies to disclose specifics regarding their operational methods — even as they test this technology on public roadways.

“This report has uncovered a remarkable absence of transparency from the AV companies concerning their use of [remote assistance operators] to assist in directing their AVs. The investigation revealed a patchwork of safety protocols across the sector, with notable discrepancies in operator qualifications, response times, and international staffing, all in the absence of any federal guidelines regulating these operations,” Markey’s office stated in its report.

Markey announced on Tuesday that he is urging the National Highway Traffic Safety Administration to examine these firms’ employment of remote assistance personnel, and that he is “developing legislation to enforce stringent regulations on AV companies’ utilization of remote operators.”

TechCrunch has contacted each company mentioned. Waymo opted not to comment. The other six did not respond immediately.

Markey initiated his investigation in February following a Senate Commerce Committee hearing focused on the future of self-driving vehicles. At that hearing, Waymo’s chief safety officer Mauricio Peña discussed how the company’s vehicles occasionally require direction from “remote assistance” staff when encountering challenging or unanticipated situations. Peña also disclosed that roughly half of Waymo’s remote assistance team is situated in the Philippines.

Over the years, autonomous vehicle companies have intermittently addressed these types of remote assistance operations. However, those discussions were often speculative, as the technology remained in its early testing stages.

Now that numerous companies have commercially introduced robotaxis or, in the case of Aurora, self-driving trucks, scrutiny of their complete operations has increased.

After the hearing, Markey dispatched letters to those seven firms seeking additional information about their remote operations. His office posed 14 questions to each company, including the frequency with which remote staff provide guidance to autonomous vehicles, the size of these teams, their locations, licensing, and the security protocols they implement.

The companies’ responses — which can be read in full here — are highly varied. None directly addressed the query about how often their remote staff assist AVs, with Waymo and May Mobility specifically stating that this constitutes “confidential business information.” Tesla did not even include this question in its reply letter. The reason remains unclear, as the company has not had a North American communications team for years.

Waymo asserted in its response that enhancements to its self-driving system have “materially reduced” the number of help requests per mile that its vehicles transmit to remote staff, but it did not provide any specifics or evidence. The company mentioned that a “vast majority of requests” sent by its robotaxis to remote assistance staff are resolved by the self-driving system “before an agent even provides a response.”

Waymo was the sole company to acknowledge the use of international remote assistance personnel. While the company asserts that it ensures these workers have local drivers’ licenses, Markey’s office noted on Tuesday that a “driver’s license in a foreign location is not a substitute for passing a U.S. driver’s license examination, as road rules will almost certainly differ by region.”

All companies except Tesla contended that they either prohibit or lack the capability for remote assistance personnel to directly operate these autonomous vehicles. In contrast, Tesla claimed that its remote assistance workers “are authorized to temporarily assume direct vehicle control as the final course of action after exhausting all other available interventions.”

Tesla stated that this can only occur if a vehicle in its pilot fleet is moving at 2 miles per hour or less, and that the remote operator is restricted to controlling the vehicle at a maximum speed of 10 miles per hour.

“This capability allows Tesla to swiftly relocate a vehicle that might be in a precarious position, thus reducing the need to wait for a first responder or Tesla field representative to manually retrieve the vehicle,” the company communicated to Markey’s office.

This practice has recently attracted criticism for Waymo, which faced challenging inquiries from San Francisco city officials at a hearing this month regarding its dependency on first responders for moving incapacitated robotaxis. Waymo does possess its dedicated “roadside assistance” team, distinctly separate from its remote assistance personnel, as detailed by TechCrunch recently. However, this aspect of Waymo’s operation was not a primary focus of Markey’s investigation.

Markey’s office did extract some additional information from these companies. His report details the latency observed in these remote assistance interactions (which fluctuates by company, with May Mobility citing the longest worst-case scenario at 500 milliseconds), how certain companies attempt to keep these workers from becoming fatigued, and what measures they adopt to safeguard the data they manage.

These are inquiries that autonomous vehicle companies have dealt with for years, and obtaining answers has not been straightforward. However, with numerous commercial deployments imminent, Markey’s office will certainly not be the last to demand more information.