Why did Tennessee Williams use streetcars for his play instead of automobiles?

The names of the streetcars symbolize the theme of the play. You couldn't name an automobile or make it an essential part of the plot. The following excerpt is from Gradesaver's study guide. If you need more information I've placed the link below;

The fundamental tension of the play is this play between the romantic and the realistic, played out in parallel in the pairing of lust and death. Blanche takes the streetcars named Desire and Cemeteries, and like the French's "la petite mort," those cars and the themes they symbolize run together to Blanche's final destination. This dichotomy is present in nearly every element of the play, from the paired characterizations of Blanche the romantic and Stanley the realist, to how all of Blanche's previous sexual encounters are tangled up with death, to the actual names of the streetcars.