In these lines, imagery is used to help readers understand what?
"Standing outside Rosebank Union, I was literally falling asleep on my feet. Not a minibus insight. Eventually, my mother said, “Let’s hitchhike1 .” We walked and walked, and after what felt like an eternity, a car drove up and stopped. The driver offered us a ride, and we climbed in. We hadn’t gone ten feet when suddenly a minibus swerved right in front of the car and cut us off."