校车
As of 2016, the average age of a school bus in the United States is 9.3 years. School buses can be retired from service due to a number of factors, including vehicle age or mileage, mechanical condition, emissions compliance, or any combination of these factors. In some states and provinces, school bus retirement is called for at specific age or mileage intervals, regardless of mechanical condition. In recent years, budget concerns in many publicly funded school districts have necessitated that school buses be kept in service longer.