You're leaving out other important factors:

e) safety: there may be a risk to get mugged on your way to the car, but you can also get mugged on the way to the public transportation. However, once in your car, you hardly have to worry about someone coming to you for "something"

f) comfort: I always have a seat in my car, and I'm not compressed between 5 people and pushed around against my will

g) consistency: the car will leave when I get to it and start it, pretty much every time. The bus may be there on time today, or not, or could be full (and I have to get the next one), etc