for 121 Express by Monique Polak
The students of the 121 Express are infamous for bad behavior and Lucas knows his role on the bus will determine his social standing at his new school. Lucas is tired of being one of the nerds. When he attracts the negative attention of the cool troublemakers, he saves himself by teasing another kid. His ploy works and soon Lucas is right in the center of the mayhem on the bus. He loves his new found popularity, but when the fun and games push the bus driver to a nervous collapse and hospitalizes an elderly lady, Lucas begins to question his choices.
Publisher description retrieved from Google Books.