The calming blog Zen Habits has five reasons to drive slower and how that can improve your life. The author claims that by driving slower that their overall happiness, such a small change can make a huge difference.
A sample reason:
3. Save time? As Vadim pointed out in his email, while you think you’re saving time by driving faster, it’s not a lot of time. And that small amount of time you’re saving isn’t worth it, considering the other factors on this list. Better yet, start out a few minutes early and you’ll arrive at the same time as someone who drove faster but started later, and you’ll arrive much happier than that person to boot
Personally I prefer riding my bike over any other form of personal transport.