SINGLE-LANE TRAFFIC FLOW ON CIRCULAR AND STRAIGHT TRACKS. IN VEHICULAR TRAFFIC SCIENCE

By the mid-1960s, many experiments on the flow of traffic in a single lane with no overtaking had been conducted at the Road Research Laboratory. These have been analyzed, with the goals of gathering data on questions involving the flow-concentration relationship in steady and unsteady flow, the nature of flow in platoons, and the propagation of disturbances. It is likely that the flow-concentration relationship for steady flow is not a single curve, but is divisible into 3 or 4 separate flow regimes; as the concentration increases these may be termed platooned flow, steady flow, quasi-steady congested flow, and unsteady high-concentration flow. Results on platooned flow are of only a preliminary nature, and much research remains to be done in this area. Experiments on the propagation of disturbances confirm conclusions about the nature of the steady-flow concentration diagram and suggest that, under changing conditions, the flow is less than for a given concentration than for steady conditions.