Twist Ending
The entire story winds up being ironic. The tale winds up being narrated by a dead man. All the events comprising the narrative are presented as a recollection and conveyed in the first person. This lends the final irony a more tragic dimension.
Narrative Irony
The story begins on a note of irony as well. Although the protagonist of the story conveys the tale in the first person, it is through the mechanism of a medium. The second line of the story is "This is what she wrote—". Ironically, there is no further mention of this female spiritual medium throughout the entire rest of the story.
Class Irony
The central irony of the events leading to the twist ending is that the upper-class owner of the car dies because of exercising the privilege of class. His decision to drive a car he is unused to instead of letting his chauffeur do the job he was actually hired to do directly leads to his premature demise. By exerting the privileges of his position, he ironically engages in what amounts to suicidal actions.
Ironic Foreshadowing
The last sentence of the second paragraph of the story has the owner of the car asserting, "I can live it again--every instant of it." This declaration is in reference to the narrative of events leading to the car accident. It is an example of ironic foreshadowing. By the time the story concludes, not only can't he live it again, but he isn't even alive at all.
Existence
The first thing the narrator relates about himself following the automobile accident is, "When I became aware of my own existence once more." This will prove ironic because he actually is not aware of the state of his existence at that time. He does not know yet that he is actually dead, and his mortal existence is over for good.
