Wiktionary
bubble car
n. 1 (context rail transport informal English) a single-car multiple unit 2 A small three-wheel motor vehicle in a category between a motorbike and a car
Wikipedia
Bubble car
thumb| Heinkel Kabine
Bubble car is a subjective term used for some small, economical microcars, usually produced in the 1950s and 1960s.
Usage examples of "bubble car".
She felt as though she might melt through the floor of the bubble car at the mere thought.
I had taken a bubble car to drive out to one of the steelworks, with a reliable driver.
On the other side, I found another Bubble car only a dozen feet ahead of the last.
He pulled her backwards, into the bubble car, and punched for the basement.