Can I record (audio & video) passengers in my car as a ride share service driver (uber/lyft) using a dashcam or smartphone app?

I currently drive for the ride-share service Uber, and will also begin driving for Lyft as well. A lot of my passengers are female (I am male ), and they are often under the influence of alcohol (both males and females ). In an effort to protect passengers and myself, I am considering a dashcam that records both inside and out ( dual channel ) of the car. they record audio and video, but some allow audio to be disabled. There are also smart phone apps that work similarly. Will I be breaking any laws, wire tapping, or otherwise? Would a posted sign stating 'recording in progress ' be necessary, or do any legal good? I believe ride share services are not considered taxis, if that matters. I own the car.