I commute in to central Cambridge from a village, the journey is about 20 miles each way. Luckily it is on the Guided Bus route, so traffic isn’t a large issue. It costs me £25 for a weeks ticket. I rarely use it at the weekend, so it’s essentially £5 a day. The petrol would cost me more than that. Not to mention that I would be sat in traffic nearly all the way. Where as I now sit on a bus and watch films/TV, listen to music or read a book.
But if my job wasn’t central in the city (or on the bus route) I would have to drive, unless it was possible to bike. I’m lucky in that way.