I live in a rural area. I have a new job in the next town which is a 25 min drive away but there are always roadworks and tractors to contend with. I tend to reckon on £75/mth running costs and diesel is £150/mth.
There is also a direct train line about 10 mins walk from me, 15 min journey and another 10 min walk the other end. The train only runs every two hours but next year will run hourly. I won't get there as early as I'd like but would still be comfortably on time if the trains run reliably. The journey home is good timing except for one evening a week when I have a meeting, but I could always work late and catch the next one. All this for the princely sum of £3.85 return.
Saving £150+/mth 
But. Would it do my head in? Delays, out in all weathers with work docs and equipment, a big hill to climb to get home (good exercise!) Has anyone sacrificed the car? How do you get on? We would still have one between us for the school run. DH would be working from home.