Macroscopic Fundamental Diagram for Urban Streets and Mixed Traffic

Urban air mobility (UAM) is an emerging mode that promises to provide relief to congested urban streets. UAM relies on airspace, however, which is an exhaustible resource considering minimum aircraft separation requirements. In light of these requirements and UAM vehicle attributes, a simulation is developed to explore UAM traffic flows and congestion development. A decentralized conflict resolution scheme is employed in the form of a non-linear program (NLP) to offer improved flexibility in detours relative to past aircraft simulations. An expansion of Edie’s definitions of density and flow rate are used in conjunction with average speed to explore the relationships between traffic flow characteristics. The results find that UAM traffic flows emulate those of other modes, by following the familiar traffic patterns of build-up and breakdown captured in the macroscopic fundamental diagram. These findings also suggest the presence of a capacity of airspace that should be carefully managed by operators to achieve optimal system performance. The relationships established in this study highlight issues that UAM operators and aviation planners may face and could be used to improve the vehicle traffic modeling of other UAM models.

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A network-wide anticipatory control of an urban network using macroscopic fundamental diagram

Transportmetrica B Transport Dynamics ◽

10.1080/21680566.2021.1878966 ◽

2021 ◽

Vol 9 (1) ◽

pp. 415-436

Author(s):

Nadia Moshahedi ◽

Lina Kattan ◽

Richard Tay

Keyword(s):

Anticipatory Control ◽

Fundamental Diagram ◽

Urban Network ◽

Macroscopic Fundamental Diagram

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A Modified Cellular Automaton Model for Accounting for Traffic Behaviors during Signal Change Intervals

Journal of Advanced Transportation ◽

10.1155/2018/8961454 ◽

2018 ◽

Vol 2018 ◽

pp. 1-12

Author(s):

Chih-Cheng Hsu ◽

Yu-Chiun Chiou

Keyword(s):

Microscopic Analysis ◽

Traffic Signal ◽

Traffic Signal Control ◽

Fundamental Diagram ◽

Macroscopic Fundamental Diagram ◽

Proposed Model ◽

Signal Change ◽

Ca Model ◽

Speed Adjustment ◽

Diagram Analysis

Previous cellular automata (CA) models have been developed for simulating driver behaviors in response to traffic signal control. However, driver behaviors during traffic signal change intervals, including cross/stop decision and speed adjustment, have not yet been studied. Based on this, this paper aims to propose a change interval CA model for replicating driver’s perception and response to amber light based on stopping probability and speed adjusting functions. The proposed model has been validated by exemplified and field cases. To investigate the applicability of the proposed model, macroscopic and microscopic analyses are conducted. Although the macroscopic fundamental diagram analysis reveals only a small decrease in maximum traffic flow rates with considering driver behaviors in change intervals, in the microscopic analysis, the proposed model can present reasonable vehicular trajectories and deceleration rates during slowdown process.

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