Freeway traffic flow management is an overlooked aspect of management of the Melbourne (and other Australian cities) freeway networks. As the freeway networks grow and become more interconnected, the importance of managing the traffic flows to enhance performance gets greater. Overseas studies have shown that, if free-flow conditions can be achieved, the hourly traffic throughputs are up to 30 percent greater than those after flow breakdown (i.e. when speeds drop from about 80km/h to around 30-50 km/h). The maintenance of free-flow conditions can best be achieved by a combination of suitable basic capacities (balancing lane numbers) and smoothing traffic flows that enter the freeway - typically by using ramp metering systems. The paper describes a series of studies carried out for VicRoads to assist in understanding the flow breakdown processes, and then in developing suitable practices to avoid flow breakdown or delay its onset. The studies have demonstrated that parts of the freeway system could readily be upgraded in their operation by using ramp metering. (Author/publisher) For the covering entry of this conference, please see ITRD abstract no. E205914.
Abstract