Do Not Disturb App

Your phone will still ring. Assuming your vehicle has hands free you will be able to answer calls using that. You will still be able to dictate outbound messages using Siri, get Siri to read your inbound messages, answer simple questions and call people in your address book for you.

You will NOT be able to unlock the phone by using the home button.

If you need access to any app (eg Uber driver app) I suspect you will have to turn Do Not Disturb to manual on/off.

hope that helps

Not clear whether you mean whilst driving for Uber, or as a passenger?

You have the option to turn it off in either case - see link before your post.