It seems odd to me that a heavy driver-less truck is tested on a regular expressway with regular cars which drivers have no clue that they're actually participa

It seems odd to me that a heavy driver-less truck is tested on a regular expressway with regular cars which drivers have no clue that they're actually participating in a rather dangerous test that may potentially lead to fatal casualties. It's like testing a pilot-less plane with real passengers which are not informed that their plane has no pilots. I'm glad everything went smoothly in this case, but shouldn't such testing be done in a more protected way until the technology becomes proven?