Whenever you have to travel by road to a diving point, you have to carry with a bulky bag or trunk for diving equipment (of course, in case you are not going to hire it!). And what is just something disturbing, in one way, is disgusting when you return, as most times, you had no time to dry it. That's why sometimes your car trunk gets damped and whats worse, sometimes it smells bad due to the sea water.
A very simple solution is to put your equipment in a garbage bag. This way everythig will be isolated untill you arrive home and wash and dry it.