By car, I leave my house at about 8:25 in the morning and arrive at work 16 miles away at 9ish.
There are no train stations near where I live, nor where I work so they are excluded.
My legs were injured in a car crash a few years ago, so I cannot walk or cycle to work, especially given that there are several very long steep hills.
That just leaves buses. There are no direct bus routes between my house and my place of work, however, I can get there with two buses.
I would have to leave my house at 6:40am to arrive in the centre of town at 07:29. This gives me 16 minutes to walk across the centre to the bus station to get the second bus.
The second bus leaves at 7:45 and arrives near work at 8:47, with 13 minutes for me to walk 3 miles to my office.
Total travel time by bus: 2h 23m
Total distance by bus: 28 miles.
This is, of course, assuming that the buses run on time and are not held up by traffic, roadworks or cyclists.
Now here is the best bit, a bus ticket will cost me £21.50 per week. I work 47 weeks per year so the annual cost for using the bus is £1,010.
My car uses £70 per month in petrol, which over the same time period works out at £822. A considerable saving! (annual road tax and insurance not taken into account as I need to use a car anyway)
If I take my car I don't have to sit next to a tramp or students with noisy tsch tsch tsch music. I don't have to walk 5 miles in the cold wet winter weather to get to my car. I have heated seats, air conditioning, surround sound music and everything else in my personal space.
This is why I don't use public transport. If a bus would like to pick me up outside my house and drop me off at the door to my office then I will obviously reconsider.
For the record, my carbon footprint is 8.12 tonnes per year, a fair bit less than the 10 tonnes per year average for the UK. I use energy saving light bulbs, always turn lights out when not in the room, central heating almost never on (I don't feel the cold), never leave things plugged in or on standby, turn things off at the wall and so on.
You can calculate your carbon footprint here: http://footprint.wwf.org.uk/.
The thing I found amusing is that section 1 describes your diet. Question 1 asks what kind of diet you have. Being a vegetarian I select "Vegetarian". Question 2: How often do you eat meat? duh!
Another site is the UK government calculator which calculated my footprint at 3.58 tonnes. Again, I am less than the national average of 4.46 tonnes.
By the way, don't compare the two sites results. They use completely different analysis techniques and mathematical models to calculate the results. No idea which one is accurate.