The car involved is supposed to be cursed:
From Snopes
"...General Potiorek became the next owner of the car. Several weeks into the war his armies suffered a rout at the hands of the ill-organised army of Serbia. The General was summoned back to Vienna by the Emperor Franz Josef I. And there in Vienna, his reputation ruined, his sanity destroyed, he died.
[Another version adds the detail of Potiorek becoming an impoverished lunatic who eventually died in the almshouse.]
A captain of Potiorek's staff took charge of the jinxed vehicle; nine days later in a terrible accident he killed two peasants on the road before swerving into a tree and killing himself.
After the war, the governor of newly independent Yugoslavia took charge of the car. He endured a succession of terrible accidents, one of which cost him his left arm. [Four accidents in four months, according to another source.] The car was then sold to a doctor, who was crushed to death when he overturned it into a ditch. [He had the car six months before it "turned" on him.] The next owner was Simon Mantharides, a diamond dealer. He fell to his death from a precipice. [The other version gives a slightly different sequence of events. According to it, the car passed from the crushed doctor to a wealthy unnamed jeweler who enjoyed it for all of a year before commiting suicide. Its next owner was yet another doctor, one whose patients deserted him out of fear for his cursed car.]
The car passed into the hands of a Swiss racing driver who was later killed in an accident in it. [Thrown over a stone wall to his death, says another source.] A Serbian farmer, who paid a fantastic sum for the car which had acquired great historical value, was the next owner and victim. He cadged a tow from a horse and cart one morning because the engine would not turn over. He forgot to switch off the ignition and the engine caught suddenly. The car lurched forward into the horse and cart, and overturned, killing the farmer.
Finally, a garage owner lost his life in the car returning from a wedding. He tried to overtake a long line of vehicles and was killed as the car spun out of control. [On his way to the wedding, says the other version. And the spin out killed both him and four of the six friends with him.]
The car now rests harmlessly in a Viennese museum. It is never taken out on the road."
From Snopes
"...General Potiorek became the next owner of the car. Several weeks into the war his armies suffered a rout at the hands of the ill-organised army of Serbia. The General was summoned back to Vienna by the Emperor Franz Josef I. And there in Vienna, his reputation ruined, his sanity destroyed, he died.
[Another version adds the detail of Potiorek becoming an impoverished lunatic who eventually died in the almshouse.]
A captain of Potiorek's staff took charge of the jinxed vehicle; nine days later in a terrible accident he killed two peasants on the road before swerving into a tree and killing himself.
After the war, the governor of newly independent Yugoslavia took charge of the car. He endured a succession of terrible accidents, one of which cost him his left arm. [Four accidents in four months, according to another source.] The car was then sold to a doctor, who was crushed to death when he overturned it into a ditch. [He had the car six months before it "turned" on him.] The next owner was Simon Mantharides, a diamond dealer. He fell to his death from a precipice. [The other version gives a slightly different sequence of events. According to it, the car passed from the crushed doctor to a wealthy unnamed jeweler who enjoyed it for all of a year before commiting suicide. Its next owner was yet another doctor, one whose patients deserted him out of fear for his cursed car.]
The car passed into the hands of a Swiss racing driver who was later killed in an accident in it. [Thrown over a stone wall to his death, says another source.] A Serbian farmer, who paid a fantastic sum for the car which had acquired great historical value, was the next owner and victim. He cadged a tow from a horse and cart one morning because the engine would not turn over. He forgot to switch off the ignition and the engine caught suddenly. The car lurched forward into the horse and cart, and overturned, killing the farmer.
Finally, a garage owner lost his life in the car returning from a wedding. He tried to overtake a long line of vehicles and was killed as the car spun out of control. [On his way to the wedding, says the other version. And the spin out killed both him and four of the six friends with him.]
The car now rests harmlessly in a Viennese museum. It is never taken out on the road."