Origins: Making no claims as to the story's veracity, I merely present this item from a 1955 newspaper article:
Jobe's arm, protruding from the window of his car, had struck the end of a power shovel being hauled on a flat-bed truck.
The blow ripped off his arm, which dropped to the pavement. While witnesses watched, his car swerved slightly and then went on.
Police were summoned and they conducted a fruitless search.
He drove eight miles and finally stopped at a grocery store, where people gazed in astonishment at his bleeding shoulder, then called police again.
Jobe said he doesn't remember the accident, but said he just remembers looking down and noticing his arm was gone. Then he stopped his car.
His condition was reported satisfactory today.
Last updated: 14 April 2011
Los Angeles Times. "Arm Torn Off, Driver Goes on 40 Minutes; Too Dazed to Notice." 17 July 1955 (p. 1).