"They have driven a car" means ever, in their lives - it could have been 50 years ago.
"They have been driving" means it recently stopped, or with further explanation it could be continuing. eg Q: "Why is James angry?" A: "He has been driving a car".
However, it could also mean continuing "I have been driving a car for six hours".
Present continuous would mean the same thing, in principle: "I am driving". Note, you can't say "I am driving for six hours" to describe an action that is happening now, in this case the present continuous would be a future plan and would need further explanation: "I am driving for six hours on Thursday!"