traction

Traction refers to the frictional grip that enables a vehicle or object to move, or to transmit force from a driving surface to the object. It is determined by the normal load, the adhesion between surfaces, and surface conditions. Greater traction reduces wheel slip and improves acceleration, braking, and steering. In road vehicles, tires must maintain grip on dry, wet, icy, or uneven surfaces, and traction control systems adjust torque and braking to prevent loss of grip.

In rail transport, traction denotes propulsion transmitted through wheel-rail contact. Locomotives power driven wheels via traction motors; the amount of friction between wheel and rail governs performance and safety. Wheel slip during starting or climbing grades is mitigated by control systems that limit torque or apply braking to slipping wheels.

Medical traction is a treatment used to align or immobilize fractures or deformities by applying a pulling force via weights, cords, pins, or frames. External skin traction places traction on the skin and soft tissues; skeletal traction uses pins or wires anchored in bone. Traction aids healing by maintaining alignment but carries risks such as skin irritation, infection, nerve or vessel injury, and prolonged immobilization. Duration depends on injury and bone healing.

In business and entrepreneurship, traction refers to evidence of demand or momentum for a product or service. Investors and analysts look for metrics such as user growth, engagement, activation, revenue, or customer retention to gauge product-market fit. Achieving traction often involves early pilots, partnerships, and iterative product development, and is used to justify further investment or expansion.