Sen. Ed Markey’s recent investigation has exposed the stark lack of transparency in autonomous vehicle (AV) technology, with Waymo leading the pack in mumbling.

The senator sent questions to seven major AV companies and got nothing but silence. Tesla admitted that its remote assistance workers can take temporary control, but for now, the truth remains obscured.

Markey is not backing down; he’s calling on NHTSA to investigate and pushing for legislation to regulate the use of remote operators in autonomous vehicles.

The issue isn’t limited to Waymo. Aurora, May Mobility, Motional, Nuro, Tesla, Zoox — all have their secrets, and it seems that transparency is not a priority when profits are on the line.