A school bus is a bus use to transport children and adolescents to and from school and school events. The first school bus was horse-drawn, introduced in 1827 by George Shillibeer for a Quaker school at Abney Park in Stoke Newington, London, United Kingdom and was designed to carry 25 children. The bus has subsequently become a major mode of transportation, particularly for transporting children to school. Children may travel to school on regular public bus services. In some cases public bus services may run field trips and high school athletic events, and private coach services may put on their own paid services. In North America, however, the school bus is itself a specific type of bus distinct from other buses. Canada and the United States have specially built, painted and equipped school buses. They are commonly painted a "yellow-orange" color (officially known as "National School Bus Chrome Yellow") for purposes of visibility and safety and equipped with specialized traffic warning devices, with the exception of school activity buses (normally used exclusively for point-to-point field and athletic trips and not used for home delivery routes) which are built to the same standards but are customarily some color other than yellow-orange and also often not equipped with traffic warning devices. Most school buses purchased in recent years have been diesel-powered or hybrid. Full-size school buses can seat 59 to 90 passengers, but in many districts smaller vehicles are used as well. Such smaller vehicles are commonly known as "short buses", and are often used for low-density routes associated with private schools and for magnet programs, as well as those for developmentally-challenged students. Engine manufacturers include International, Genesis, Ford, Mack, and others; whereas bus bodies are manufactured by Blue Bird, Thomas and IC Corp.