Fear and Logic
A close friend of mine possessed an extreme fear of guns. There was nothing in her experience that sparked the fear. She just had it.
I was baffled by her reaction since I grew up around guns and have always regarded them as a tool, much like a hammer or a buzz saw.
So it is with many fears. You can find combat veterans who are terrified of public speaking and great orators who freeze up when writing. I knew an attorney who spent decades in Phoenix, hardly a bastion of public transportation, without driving a car. It is difficult to imagine the extra work he had to do to accommodate that lifestyle.
Logic only goes so far in countering fears. The needed courage must be found through the steady and frequent performance of courageous deeds. I know of no other solution.