Beth is Rachel's younger sister, diagnosed with an intellectual disability, who finds joy and community in riding city buses. Her independence and vibrant personality are central to her daily life and her relationship with Rachel.

Jesse is Beth's long-term boyfriend, who has also been diagnosed with an intellectual disability. Despite societal challenges, he maintains a strong bond with Beth and has a passion for cycling.

Olivia is Beth's aide, offering support and understanding throughout the book. Her insights into Beth's life and needs are instrumental in shaping Rachel's perspective.

Jacob is one of Beth’s favorite bus drivers, a kind and religious man who has overcome personal challenges. He becomes an important figure in Beth’s life through his encouragement and support.

Rick is a bus driver whom Beth attempts to set up with Rachel; he becomes a supportive friend to her. His kindness plays a role in Rachel's personal growth.