For me driving was a problem while I was on water. But again I live in NYC, driving is stressful anyway and you don't want to be stressed while you fast. I think it is very individual. Steve (Mouseclick) said that fasting doesn't affect his driving abilities when I asked that question before.
I want to start my fast tomorrow morning. And I have to be active on this forum as I said the first few days, otherwise I start feeling lonely, bored, disconnected etc. I am starting my mental preparation now.
Julia