No SRS,( Supplemental Restraint Systems ) in Class A' s, probably because of the distance from the steering wheel for the driver and the angle the steering column comes up through the floor. In the event of a crash severe enough to deploy the air bags in a passenger vehicle , it is possible for even a properly restrained driver ( Shoulder belt on) to contact the steering wheel. Particularly if the steering column is pushed towards the driver. Avoiding that contact , to the face and upper body, is the protection the SRS provides.
Same for a passenger, distance from the dash is such that there is no way to produce a SRS large enough to do any good in the 1/30 of a second that the SRS needs to deploy in, to be effective.
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.