Donald Duck's car is known as the 313 due to its license plate number. It originated, without its trademark license plate, in the 1937 short Don Donald. In it, Donald trades his burro for the car and takes his girlfriend Donna Duck (the precursor to Daisy Duck) for a drive through the desert. Unfortunately for the both of them, the car eventually breaks down and malfunctions, eventually ruining their afternoon.
Al Taliaferro introduced the car, a 1934 Belchfire Runabout, into the Donald Duck newspaper comic on July 1, 1938. Donald is said to have constructed it himself from spare parts of various sources. It is recognizable by its license plate number 313. The car is modeled around the 1938 American Bantam. Though Donald briefly drove other cars both in Taliaferro's strip and in later stories, this car would stay with Donald throughout the following decades. The car's constant breakdowns and need of repairs is often used as a source of humor. Immediately recognizable by readers, it seems to have become as much a trademark of Donald as his sailor shirt and cap. On the other hand, his alias the Duck Avenger has the 313 (which sports a different plate, namely X, so it's nicknamed 313-X or 313-Xtreme) equipped with a lot of high tech gadgets by Gyro Gearloose to combat crime. In Recalled Wreck by Don Rosa, Donald tells his nephews that he can't buy new car parts instead of having them fixed because his car is made of parts that are no longer produced.
It is said that Donald Duck's license plate number is 313 because he was supposed to have been born on the thirteenth of March.