Juan has made this bus run many times, and he is bored with the dull routine. This time, however, the heavy rain that has fallen makes a bridge unsafe, and so he asks the passengers to decide whether to return to Rebel Corners or attempt to reach their destination via an old dirt road. They choose the road. En route, he deliberately runs the bus into a ditch, telling the passengers it was an accident. The symbolism here is, by Steinbeck's standards, unusually heavy-handed: Juan, whose life is trapped in a figurative rut, escapes it by driving into a literal rut.