If you have a good job/career and making good money hang on to it, good jobs are very hard to come by.
If it is just a ho mum job that you don't care about then that is different.
A car is just a tool much like a bike, don't feel guilty for driving, I have a car that I will drive if my commute involves cycling in a blizzard, thunderstorm/hail storm.
It sounds like a car is sometimes a necessary tool for to do your job on occasion.
Bike when you can, drive when you should...
Guilt...naw, don't have time for that.