Unless it is a transit style school vehicle placed into operation before July 1, 2004, or it was under contract before July 1, 2004 to be purchased, a school vehicle may not be used for more than 12 years, unless the conditions for its extended use are satisfied under Education Article, §7-804(b), Annotated Code of Maryland, or it is specifically exempted by statute. A school vehicle may not be used at any time to transport students if it has been in operation for 15 years or more.