If you get them used to the car first, maybe black out the carriers, and if they react fine then I don't see the problem. Mine have been on quite a few 5/6 hour journeys and I know some people who have driven rabbits to shows in europe with no problems. But if they get very stressed out then personally I wouldn't risk it
ETA: Some ideas for getting them used to the car, start off just sitting them in the carrier with some food to nibble on, return them to their hutch/run straight after, when they're fine with that, you can sit them in the car with the engine running, again I'd have some distractions and when it's done put them straight back, and gradually increase the time, then start taking them on small journeys (preferably journeys with smooth roads). I use black paper to cover the carriers on long journeys but just selotape the top so there's plenty of ventilation