why is talking a phone considered a distraction....but talking to someone that is sitting beside you or behind you not???
Because it doesn't require taking up your hands and doesn't affect hand-eye coordination. Which is why to help solve this, with newer cars, you can just do a bluetooth connection from your car's stereo to your phone (like for music) -- but also use it to answer the phone if someone calls... or to call them them when you're in the parking lot, and move along chatting. Won't distract you any more than changing the radio station to answer/hangup.
I don't have one of those setups in my car (don't drive enough; no need for nice setup on the dash) -- but every once in a while I'll get an eyebrow raised that I didn't answer my phone when I was on the road. I always say -- I don't answer my phone when on the road. I will peak at it to see who called/texted when seemingly very convenient / safe to do so, but I'm not going to hop on the phone when on the road as that does lessen one's driving ability.