There are a number of reasons. Firstly I got turned off of driving by my driving instructor at school who was a grumpy cranky old man. Also I have this issue where I will just space out at times, no matter how important the thing is I should be paying attention to, and I don't think that it would be entirely safe for me to drive. An example of me spacing out is when I was riding my bicycle a number of years ago and began calculating powers of two in my head. I had gotten through about the first fifteen when I ran into the back of a parked car. It just startled me at the time, but if I'd been driving down the street at forty miles an hour the results would have been very different. I also think that the cost of our current automobile obsessed society far outweigh the benefits in lives lost (Just think if there was a weight loss drug that killed as many people every year as auto accidents do. How long do you think it would remain on the market?), resources destroyed, and environmental damage, and my not driving is a sort of silent protest to all of this.