WarpMyMind

Is it advisable? Obviously I wouldn't want to go into a trance while driving, but will the messages in a script reach my subconscious if I am focused on the road, and not the dialogue?

Don't, just, don't. A large majority of files often begin with "Do not listen while driving a car or operating heavy machinery."

People go into trances anyways while driving, it's better not to have something playing in the background that's encouraging you to go into a deep trance. It would be better to just wait until you get home. "Highway hypnosis" isn't supposed to be literal.

^What he said, said again for emphasis!

Hypnosis recordings get you to focus on them to the exclusion of other things. That is extremely dangerous when driving. Also if it is a recording you have listened to before your mind will associate it with going into hypnosis, and will do so readily.

For similar reasons if you are making your own recording and want music in the background, never use your favourite relaxing popular song / tune. Your mind will build up an association with it and hypnosis, and if it comes onto the radio while you are driving you could be in trance before you realise it.

I echo what the others have said. Unless you mean sitting in a parked car for the sake of privacy so you can go into trance. That's okay. But driving? No, no!

The act of driving in itself puts us into a trance state. Even passengers go into a funny state. We're advised not to focus on driving, both hands on the steering wheel. We're advised not to take calls on our mobile phones while driving, even with a hands free kit.