1. As little as I reasonably can. (Ah, but what is reasonable?)
2. When I need to, as short as I can. If you call me, my usual response is, "I'm driving, can I call back later?"
3. If I have a choice, in a place where driving is as safe as possible. (Freeway driving requires much less active attention than city streets, as long as you can see what is going on waaay ahead.)
4. The road always comes first. If I catch myself failing to have done regular scans of mirrors and location of nearby cars, this phone call is over.
All of that said, I still feel a minor twinge of guilt every time I call home to give an ETA for when I'll get there. But not much, because it would be more dangerous for me to take the time to get off the road, park, make my call, then get back on the interstate.
Here are my rules for using the phone in the car: I don't.
If someone calls, I let it ring and go to voicemail. If I'm expecting something that may be urgent, I will pull over as soon as practical and check it. Otherwise, I will wait until I get to my destination. Really, the vast majority of the time it's something that can wait. In fact, I've never had a situation in which something critical depended on me answering right then. I tend to try to avoid getting into such situations.
How do I give an ETA? I do it before I leave. Sure, traffic might be a bit bad, and slow me down a bit, but usually that can be reasonably well predicted (based on rush hour, weekends that lots of people are travelling, etc). If my prediction is wrong? Well, life goes on. People got on just fine before the invention of cell phones. If it's a multi-hour journey and I will be substantially delayed, again, I pull off to make the call; usually there's a rest stop somewhere reasonably accessible.
Do you really think that your life is so important that you must put other people's lives at risk just to give an ETA of when you'll get there, and you can't be bothered to just plan a little in advance?
Of course, most of the time when I'm in the car, it's with someone else. I generally avoid single-occupant trips. I commute via public transit (where I can talk on the phone all I want safely, though generally limit it to be polite to other passengers) or bicycle (where again, I pull off if I need to make a call). My trips in the car are generally only for longer trips, which I share with someone else, and I can ask them to call or answer for me if I need.
If you find traffic predictable, you probably don't live in Los Angeles. As for lives at risk - my decision to commute to a client is orders of magnitude more dangerous to people around me than the momentary distraction of letting my wife know whether I'll be able to provide child care. I'm personally OK with doing that, so long as I take steps to minimize the risk to myself and others.
It sounds like your situation and/or value system is different.
I was nodding my head in agreement up until that last bit. How is it more dangerous to pull off the interstate and park (assuming you are using an offramp and not just the shoulder) than making a phone call?
The most dangerous points in a normal freeway drive are merging and lane changes. To exit and park you do multiple lane changes off and on, merge, and have to navigate local traffic signals.
Compare to remaining in your lane, in smooth traffic, when you can see well ahead and know it remains smooth, while making a call and saying, "Just letting you know it looks like I'll get there around 8:20." "OK, drive safely." click (Any other variant of this conversation ends with, "I can't talk, I'm driving." click)
If I needed to make a longer call, of course I'd leave the road. But for this, I believe that just making it is safer.
I think GP probably was talking about using the shoulder. However, keep in mind that both merging on to the interstate, and city driving are significantly more dangerous than interstate driving. Combine that with the fact that calling to give an ETA is a lot less focus-consuming that most calls, and it is plausible that staying on the interstate is safer.
Stopping on the shoulder for such a trivial reason as giving an ETA is usually illegal and a bad idea anyways, so it shouldn't even be an option to be considered.
1. As little as I reasonably can. (Ah, but what is reasonable?)
2. When I need to, as short as I can. If you call me, my usual response is, "I'm driving, can I call back later?"
3. If I have a choice, in a place where driving is as safe as possible. (Freeway driving requires much less active attention than city streets, as long as you can see what is going on waaay ahead.)
4. The road always comes first. If I catch myself failing to have done regular scans of mirrors and location of nearby cars, this phone call is over.
All of that said, I still feel a minor twinge of guilt every time I call home to give an ETA for when I'll get there. But not much, because it would be more dangerous for me to take the time to get off the road, park, make my call, then get back on the interstate.