Since the story is told in a non-linear fashion, there is no proper climax chronologically. The most important event of the story is the crash itself, insofar as it affects the narrator's mind and his ability to understand events; he is high on speed and other drugs, and so the crash seems to him to be inevitable, although this is a product of his delusions. The resulting cleanup and investigation by the police leads the narrator to explain that he finds himself not actually part of the crash, although he was there and experienced it firsthand; he claims to have changed from "president" (as a person conscious and aware) to a bystander, since the emergency workers do not consider him critical compared to the injured people. One possible climax comes in the hospital, as the narrator describes the wife of a dead man arriving:
Down the hall came the wife. She was glorious, burning. She didn't know yet that her husband was dead. We knew. That's what gave her such power over us... She shrieked as I imagined an eagle would shriek. It felt wonderful to be alive to hear it! I've gone looking for that feeling everywhere.
"There's nothing wrong with me"—I'm surprised I let those words out.
(Johnson, "Car Crash While Hitchhiking," hotgiraffe.msk.ru)
It is this experience that most touches the narrator, not the crash itself or the inexplicable survival of the baby in the back seat. His later hallucinations are echoes of this experiences; inanimate objects become voices in his head just as he imagined the wife's screaming to have some solid form. That he went "looking for that feeling everywhere" shows how much it affected his mind; the narrator is not stable to begin with, but even the crash is not as significant as this single moment in the hospital.