School Transportation - As introduced, extends from 18 years with no more than 200,000 miles to the later of 20 years or 300,000 miles, the period for which a conventional or Class D school bus that is used exclusively to transport students from school to an after-school program may be in service; requires such buses to be inspected at least twice annually by the commissioner of safety or the commissioner's designee. - Amends TCA Title 49.