Can a passenger drink in a car in mass?

Excuse me, but I was wondering if you could clarify something for me. The paragraph mentions "Can a passenger drink in a car in mass?" and it has me a bit confused. Are you referring to whether or not a passenger is allowed to consume alcohol while in a moving vehicle, and if so, does the term "in mass" mean that multiple passengers can all be drinking at the same time? Or is there another interpretation of this phrase that I'm missing? I'd appreciate any clarification you could provide.