Is there any type of road that you are scared of driving upon? Not just a case of don't like it, but would you say that if you had a choice between driving on a motorway and having pins stabbed into your eyes, you would go for the pin option?
It is unknown how many people are affected, because like the subject of AIDS and homosexuality in the 1980's, this is a topic which those affected will want to keep to themselves.
But it is a problem that is getting worse. In a lot of cases, this is a symptom of our modern day lifestyle, and as we place more and more pressures on ourselves to be as we believe the world would have us be, so conditions such as this will become more comon.
Driving Fears, Phobia and Anxiety 
