This is a story that I would guess was in the late 1960's to early 1970's. The story line is of a boy going for his driver's license exam. I don't remember how but he "finishes the exam" and is driving home. There is an accident while he is driving and his friend is killed. He is grief stricken but then the examiner "wakes" him and tells him it was the last part of the exam. That it didn't really happen. The boy asks when he can get his license. And fails because he should not have wanted to drive that soon after such a trauma.
The story you are looking for is Test by Theodore Thomas.
Evidence that it is either the correct answer or a very similar story can be found here:
“Test” is a fascinating story about Robert Proctor, who represents young enthusiastic people wanting to drive and the state authority conducting a test to see whether he is fit to get a driver’s license. Though the fantasy fiction describes the concerns of the government in preventing and controlling accident, Thomas surprises the reader with a very unique way to test people on their driving skill. It provides us a glimpse on the imaginary invention of the future consisting of futuristic elements of science fiction, action stories and realism.
Although Robert Proctor behaves responsibly, he is denied his license and he is taken away by the authorities. He feels responsible for the death of his mother and the girl in the car which loomed ahead of him though nothing happened in reality. The vivid image of the girl’s face in his head, along with his mother’s cry lingers in his mind after the hypnosis. This is where Thomas integrates the two plot, and surprises the reader that the emotions that ran through him are true and real, but has been intentionally misled by the testing people (the authorities), because the act of hypnosis itself is a process of events that takes place in the mind under the direction of a second person.
Theodore Thomas published between the early 1950s to the late 1970s, which matches the timeframe of your story (source: http://en.wikipedia.org/wiki/Theodore_L._Thomas)