I don’t carry out conversations via text message while driving, but if I’m running late to an appointment and someone texts me asking where I am, I’ll reply with a quick “be there in 5”, when traffic conditions permit.
I will sometimes enter my destination into Google Maps on my iPhone while driving, or bring up Google Maps to see if there is traffic on the highway. If I need to do anything more involved than this, I’ll pull over or wait until I end up at a red light or something.
I don’t do this on crowded or busy streets where there could be pedestrians present, or cars pulling out of driveways, etc.
On rare occasions if I’m driving on the interstate through the middle of nowhere I’ll check for new emails on my phone or something like that.
I talk on the phone while driving whenever the need arises. Never had any close calls or found it to affect my concentration anymore than talking to someone in the car with me. Yes, at times I get distracted by the conversation, but that happens regardless of whether I’m talking on the phone or with someone in person.
In fact, in thinking about this now, I tend to have move lively and engaged conversations with passengers in person, and am more likely to make mistakes in that situation than when talking to someone on the phone. I will occasionally forget to take an exit on the highway or end up in the wrong lane approaching an intersection or something, and I tend to make those mistakes almost exclusively when talking to other people who are in the car with me.
All that said, I love driving and it is a completely effortless, relaxing, stress-free experience for me that seems to require no mental energy whatsoever. I know some people who find it incredibly taxing and stressful and have a hard time driving competently even when they’re able to devote 100% of their attention to it, and certainly I can understand how those people would perform poorly while interacting with a cell phone or whatever at the same time.
I am also a pilot, and being able to multitask while hand-flying the plane (e.g. maintaining altitude, attitude, airspeed while reading a chart, talking on the radio, operating the instruments) is a basic requirement for getting a license. Of course, no pedestrians are going to jump out in front of you at 5,000 feet AGL either…