 says students need to practice safety as well. When walking, make sure to cross streets at corners or march crosswalks that are in clear view. Never cross between parked cars. Remind children to always walk in front of the bus, never behind it. Speed limits in school zones are 15 miles per hour. Seatbelts are a must, click it or ticket. Classes start on Thursday, August 1st in the Prescott and Humboldt Unified School Districts, while students in the Chino Valley Unified School District return on Monday, August 5th.