Autonomous self-driving cars are continuously surveying their surroundings using an array of sensors and recording this to memory.
In the event of an accident of malfunction, this data can be retrieved for analysis.
However, this data could also be retrieved as surveillance data – even when the vehicle itself has not been in an crash.
Consider, a bike versus human driven car crash at an intersection. Two other vehicles at the intersection are autonomous vehicles and they have recorded the entire scenario, in detail, including subject and object positions and travel speeds.
All of this data is available to the police. Police agencies that today operate their own license plate readers and intersection surveillance cameras might choose to contract with autonomous vehicle companies for use as public data collection systems. When your autonomous vehicle is connected to your EV charging station, it might communicate over WiFi to upload collected data to a master database.
This is not particularly difficult or far fetched and police may already have the legal authority to pursue this collection.