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Walking school buses, in which a supervising adult escorts a group of children on foot along a fixed route to school, emerged as a response to growing concerns about both traffic congestion near school gates and declining rates of childhood physical activity. Unlike a formal bus service, the route typically follows existing footpaths and picks up children at designated points along the way, much like bus stops. Advocates note that the model requires no vehicles or fuel, making it inexpensive to establish compared with expanding a traditional bus fleet. Its main limitation is reliance on volunteer supervisors, since a shortage of available adults on a given day can mean the route cannot run, leaving families to arrange alternative transport at short notice.