Performance Of Urban Networks Research Articles

Simulation analysis of urban network performance under link disruptions: Impacts of information provisions in different street configurations

This study uses aggregated network-level operation metrics to examine the performance of three street network configurations, namely two-way (TW), two-way without left turns (TWL), and one-way networks (OW), under disruptive events in the network. Overall, a TWL network is found to be the most efficient both with and without disruptions. When there is no disruption, a TWL network shows a comparable trip completion rate as a TW network with turn pockets at intersection. Although the mean travel distance in the TWL network is about 30% higher than the TW network, its mean trip time is only 16% higher due to lower intersection delays. When disruptions take place, only TWL network is found to accommodate the most challenging ones in the central area due to its higher intersection efficiency and more evenly distributed traffic inside. The study also examined the impacts of various ITS-related strategies to provide drivers with advanced information on the disruption to mitigate its negative effects. The results revealed that providing information on disruptions that occur outside the most congested areas when vehicles start their trip might actually reduce overall network performance, since doing so may cause vehicles to reroute through heavily congested areas. For disruptions in the central region of the network, alerting drivers just one or two blocks upstream of the disruption can achieve similar delay reductions to broadcasting the disruption to 75% of road users.

Economic Model Predictive Control of Large-Scale Urban Road Networks via Perimeter Control and Regional Route Guidance

Local traffic control schemes fall short of achieving coordination with other parts of the urban road network, whereas a centralized controller based on the detailed traffic models would suffer from excessive computational burden. State estimation for detailed traffic models with limited observations and unpredictability of individual driver behavior create additional complications in the applicability of these models for large-scale traffic control. This point toward the need for designing network-level controllers building on aggregated traffic models, which have recently attracted attention through the macroscopic fundamental diagram (MFD) of urban traffic. Under some conditions, the MFD provides a unimodal, low-scatter, and demand-insensitive relationship between vehicle accumulation and travel production inside an urban region. In this paper, we propose MFD-based economic model predictive control (MPC) schemes to improve mobility in heterogeneously congested large-scale urban road networks. For more realistic simulations of urban networks with route guidance actuation-based control, a new model with cyclic behavior prohibition is developed. This paper extends upon earlier works on perimeter control-based MPC schemes with MFD modeling by integrating route guidance type actuation, which distributes flows exiting a region over its neighboring regions. Performance of the proposed schemes is evaluated via simulations of congested scenarios with noise in demand estimation and measurement errors. Results show the possibility of substantial improvements in urban network performance, in terms of network delays and traveled distance, even for low levels of driver compliance to route guidance.