> When I got a new car with bluetooth calling, all of a sudden I was fumbling a lot less. A call is now about the same level of distraction as having a passenger or 2.

Most studies that have actually tested it have found that talking with someone on a phone, even if hands free, is much more distracting than talking to a passenger.

A big factor is that a passenger is much more likely to be aware of road and traffic conditions and stop the conversation during situations where the driver needs to pay extra attention to driving.

Sounds plausible that it's more distracting, but I'm not convinced that the difference is more varied than found among different types of passengers (back-seat driver/kids/dumb friends/audiobook(?) etc)

If you have a few studies that show more than that, I would be glad to check it out.

I don't know of any that have looked at different types of passengers. They have usually just compared an adult passenger talking with the driver to an adult on a phone talking with the driver.

Here was a recent study that was pretty interesting: https://news.illinois.edu/blog/view/6367/204502

Here's an older one: https://www.sciencedaily.com/releases/2008/12/081201081917.h...

thanks, I appreciate the links :)