When there's a crash, all information related to the crash should be public information: all raw telemetry information collect by the car, and the logic used to evaluate that telemetry. The idea any portion of this is proprietary is dangerous. If a police officer asks a human driver questions, and they refuse to answer, they can be compelled. If they are asked if they can think of anything else relevant that hasn't been explicitly asked about the accident, and they say no, and it turns out they did and were withholding information, that's a crime.
There must be equivalents for autonomous driving. They can't be allowed to shield themselves behind "proprietary information" claims.
In the United States lying to local police is generally speaking not a crime (certain lies can be, but saying you have no further information when you do is not one of them). Also you cannot be compelled to be a witness against yourself so you have every right to not answer questions if you suspect you are under a criminal investigation.
That being said in the United States non-human persons such as corporations have no such rights.
There must be equivalents for autonomous driving. They can't be allowed to shield themselves behind "proprietary information" claims.