Dynamics of Lane Distribution Flows in Freeways

Lane density and lane flow distribution are utilised in the current study as characteristics of traffic dynamics for control and planning purposes in freeways with ITS systems. As part of an on-going research, the Lane Flow Distribution Ratio (LFDR) and the Lane Density Distribution Ratio (LDDR) were introduced as main scalability factors for congestion evolution estimation. The preliminary exploratory analysis from LFDR, LDDR, traffic and spatiotemporal parameters along with link fundamental diagrams, indicated dependence between lane vehicle allocation and impending congestion emergence, in terms of traffic levels. This led to a partial parameterisation of driver’s behaviour during peak hours, that was studied in several contexts, namely at mainline, on-ramp and off-ramp locations. The assessment of the developed model was conducted based on observations derived from a freeway site in California. The site is operating during peak hours with high congestion level. Further on this approach, decision thresholds for a number of ITS policies could be derived, to adapt accordingly to control policies (eg. hard shoulder operation, VSL, ramp metering).