peloton

In a road bicycle race, the peloton (from French, originally meaning 'platoon') is the main group or pack of riders. Riders in a group save energy by riding close (drafting or slipstreaming) to (particularly behind) other riders. The reduction in drag is dramatic; riding in the middle of a well-developed group, drag can be reduced to as little as 5–10%. Exploitation of this potential energy saving leads to complex cooperative and competitive interactions between riders and teams in race tactics. The term is also used to refer to the community of professional cyclists in general. Definition More formally, a peloton is defined as "two or more cyclists riding in sufficiently close proximity to be located either in one of two basic positions: (1) behind cyclists in zones of reduced air pressure, referred to as ‘drafting’, or (2) in non-drafting positions where air pressure is highest. Cyclists in drafting zones expend less energy than in front positions." A peloton has similarly been defined "as a group of cyclists that are coupled together through the mutual energy benefits of drafting, whereby cyclists follow others in zones of reduced air resistance." A peloton is a complex system, which means that collective behavior emerges from simple rules of cyclists' interactions. Formations Pelotons are typically observed during bicycle races in which drafting is permitted, although pelotons also form from cyclist commuter traffic. Pelotons travel as an integrated unit in which each rider makes positional adjustments in response to the movements of adjacent riders and those ahead. Riders at the front are fully exposed to wind resistance, hence they experience higher fatigue loads than riders in drafting positions. After a period of time in front, leading riders maneuver farther back in the peloton to a drafting position to recover. Thus the peloton is in fluid motion as a continuous rotation of riders push from the back through to the leading edge, then falling away. Like bird flocks, peloton-like behavior that involves drafting or similar energy-saving mechanisms has been identified in a variety of biological systems.