>The results indicate that passenger conversations differ from cell phone conversations because the surrounding traffic not only becomes a topic of the conversation, helping driver and passenger to share situation awareness, but the driving condition also has a direct influence on the complexity of the conversation, thereby mitigating the potential negative effects of a conversation on driving.
Thanks for the links, learnt something new. The bit about the cognitive load preparing to speak or speaking rather than passive listening was interesting.
Yes, when talking to someone in the car they should be aware of the traffic and pause the conversation, where you have to tell the person on the other end of the phone that you need to go.
Listening to music is passive (yes, even if you happen to be singing along, as you're just parroting memorized lyrics), whereas during a phone call, you have to focus on what the other party is saying, and formulate sentences to answer them.
There are worst things like eating or talking to someone else in the car. (look at the road not the person when you're talking)