I just try to be not contactable when in the car. Doesn't work all the time but I only make/take high priority calls.
I agree... and you're right, not always possible.
In response to TPL's query from a month ago, it's not so much a desire to take the all-important call at any time as a demand from clients now-a-days. There is an expectation that cells (and blackberries) make us available anywhere, anytime, 24-7. If I'm not able to receive a call, I might lose business.
I completely understand that if ones job where the "office time" involves being in the car driving between customer sites/meetings that a BB or similar and being able to answer/make calls at 120 km/h is necessary.
Although I worked for a consultancy it was not necessary for me to be available outside my work hours of about 07:45 to 16:45. My group did have major customer in the UK but I was never involved in support.
However, in years past long before cell phones I have spent my share of evenings, nights and even one Xmas day supporting customers by phone and slow speed modem!