Early horse-drawn wagons used to carry rural students in North America were called kid hacks.
The name referred to a horse-drawn vehicle adapted to carry children who lived too far from a one-room school to walk. A “hack” was a type of carriage, ultimately related to “hackney carriage.” Kid hacks were often repurposed farm wagons, with wooden benches and little protection from weather.
These vehicles usually loaded passengers from the rear, partly because that arrangement was practical and less likely to frighten the horse. By the early 20th century, detachable kid-hack bodies were being mounted on motor-truck chassis. By the late 1920s, manufacturers increasingly built dedicated school buses instead.
A common mix-up is calling every early student vehicle a stagecoach or omnibus. Those were general passenger vehicles, whereas “kid hack” specifically describes the rural school transport wagon. The old rear entrance also survives as an emergency-exit feature on many modern school buses.