scholarly journals Macroscopic Traffic Dynamics in Urban Networks during Incidents

2020 ◽  
Author(s):  
Sasan Amini ◽  
Gabriel Tilg ◽  
Fritz Busch
Keyword(s):  
Hysteresis Loop ◽  
Network Performance ◽  
Route Choice ◽  
Urban Traffic ◽  
Incident Management ◽  
Fundamental Diagram ◽  
Traffic Dynamics ◽  
Urban Networks ◽  
Wide Range ◽  
Traffic Incident Management

The degradation of road network performance due to incidents is a major concern to traffic operators. The development of urban traffic incident management systems requires a comprehensive understanding of traffic dynamics during incidents. Recently, the concept of the macroscopic fundamental diagram (MFD) contributed to such an understanding and has been used in a wide range of applications. However, the MFD is merely reproducible under recurring traffic patterns. Motivated by a few studies which argue the existence of the MFD with a clockwise hysteresis loop during incidents, we tackle this limitation of the MFD and propose a framework to study the characteristics of the MFD under non-recurring congestion. More specifically, we introduce a criticality score (CS) which represents network redundancy and postulate that links with a higher level of CS impose a larger hysteresis loop on the MFD. We design an experiment in a microscopic traffic simulation to study the relation of closed links and the resulting MFDs. The results confirm our postulation and we observe that links with similar CS have a comparable impact on the shape of the MFD. The main contribution of this paper is the possibility to develop a framework for incident detection in urban networks under limited sensor coverage. However, the findings of the study may strongly rely on the assumptions, for instance, the network structure, the OD pairs, and drivers route choice during incidents. Thus, future studies are required to study other network topologies as well as more realistic driver route choice during incidents.

scholarly journals Macroscopic Traffic Dynamics in Urban Networks during Incidents

2020 ◽  
Author(s):  
Sasan Amini ◽  
Gabriel Tilg ◽  
Fritz Busch
Keyword(s):  
Hysteresis Loop ◽  
Network Performance ◽  
Route Choice ◽  
Urban Traffic ◽  
Incident Management ◽  
Fundamental Diagram ◽  
Traffic Dynamics ◽  
Urban Networks ◽  
Wide Range ◽  
Traffic Incident Management

The degradation of road network performance due to incidents is a major concern to traffic operators. The development of urban traffic incident management systems requires a comprehensive understanding of traffic dynamics during incidents. Recently, the concept of the macroscopic fundamental diagram (MFD) contributed to such an understanding and has been used in a wide range of applications. However, the MFD is merely reproducible under recurring traffic patterns. Motivated by a few studies which argue the existence of the MFD with a clockwise hysteresis loop during incidents, we tackle this limitation of the MFD and propose a framework to study the characteristics of the MFD under non-recurring congestion. More specifically, we introduce a criticality score (CS) which represents network redundancy and postulate that links with a higher level of CS impose a larger hysteresis loop on the MFD. We design an experiment in a microscopic traffic simulation to study the relation of closed links and the resulting MFDs. The results confirm our postulation and we observe that links with similar CS have a comparable impact on the shape of the MFD. The main contribution of this paper is the possibility to develop a framework for incident detection in urban networks under limited sensor coverage. However, the findings of the study may strongly rely on the assumptions, for instance, the network structure, the OD pairs, and drivers route choice during incidents. Thus, future studies are required to study other network topologies as well as more realistic driver route choice during incidents.

Investigation of Bimodal Macroscopic Fundamental Diagrams in Large-Scale Urban Networks: Empirical Study with GPS Data for Shenzhen City

2019 ◽  
Vol 2673 (6) ◽  
pp. 114-128 ◽  
Author(s):  
Chongxuan Huang ◽  
Nan Zheng ◽  
Jun Zhang
Keyword(s):  
Large Scale ◽  
Gps Data ◽  
Fundamental Diagram ◽  
Traffic Dynamics ◽  
Modeling Tools ◽  
Great Opportunity ◽  
Urban Networks ◽  
Macroscopic Fundamental Diagram ◽  
Analytical Approximations ◽  
Shenzhen City

This paper investigates traffic dynamics in bimodal urban networks utilizing the macroscopic fundamental diagram (MFD) and the three-dimensional macroscopic fundamental diagram (3D-MFD), which are network-level traffic flow modeling tools. Although the existence and the properties of the MFD have been extensively analyzed with field data in literature, few empirical studies examine these features of the 3D-MFDs for large-scale networks. For this work, GPS data for cars and buses running in the network of Shenzhen city in China are available for analysis and this offers a great opportunity for the investigation. Interestingly, both MFD and 3D-MFD dynamics are reflected in the data. Network partition is performed to reduce the hysteresis on the MFD and the network is split into two regions for further analysis. Then the investigation focuses on the MFD relationship for buses only. The average passenger occupancy is estimated and incorporated to generate a passenger MFD (pMFD) for buses. Moreover, bus operation on dedicated bus lanes is analyzed. Having understood traffic dynamics of cars, buses, and passengers respectively, the 3D-MFDs which illustrate the joint influence of car and bus accumulations on the global network-level traffic performance are presented. Given the scatter plot of the 3D-MFDs for the two partitioned regions, analytical approximations are provided, fitting by exponential functions. These results are promising, as they confirm the traffic features that were found from simulation-based studies in previous work.

Assessing road pricing effects on a multimodal network based on macroscopic fundamental diagram hysteresis

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Amr M. Wahaballa ◽  
Seham Hemdan ◽  
Fumitaka Kurauchi
Keyword(s):  
Network Performance ◽  
Transportation Network ◽  
Hysteresis Loops ◽  
Road Pricing ◽  
Urban Traffic ◽  
Fundamental Diagram ◽  
Content Type ◽  
Macroscopic Fundamental Diagram ◽  
Travel Time Savings ◽  
Multimodal Network

Purpose Road pricing is an efficient strategy for managing urban traffic to relieve congestion. The macroscopic fundamental diagram (MFD), which relates the average network density and flow, is a simple tool for assessing road pricing effects on transportation network performance. However, recent research indicates that it may have complexity (an MFD hysteresis loop), especially for city-scale networks. Although ignoring MFD hysteresis may provide inaccurate results, pricing models that consider this hysteresis are scarce. This paper aims to assess road pricing effects on network performance considering MFD hysteresis characteristics. Design/methodology/approach This paper evaluated different pricing strategies spatially and temporally and compared network performance based on MFD shape in the presence of MFD hysteresis loops. These strategies were developed on a multimodal (cars and buses) network using a multi-agent transport simulation (MATSim). Findings This study found that pricing some links for a short duration with an optimum charge calculated based on the MFD provides higher travel time savings than the previous relevant studies. Originality/value These findings may facilitate assessing road pricing effects on multimodal network performance considering MFD hysteresis.

Urban traffic incident management in a digital society

2014 ◽  
Vol 89 ◽  
pp. 245-261 ◽  
Author(s):  
John Steenbruggen ◽  
Peter Nijkamp ◽  
Maarten van der Vlist
Keyword(s):  
Urban Traffic ◽  
Incident Management ◽  
Digital Society ◽  
Traffic Incident ◽  
Traffic Incident Management

Investigating Transfer Flow between Urban Networks Based on a Macroscopic Fundamental Diagram

2018 ◽  
Vol 2672 (20) ◽  
pp. 75-85 ◽  
Author(s):  
Sunghoon Kim ◽  
Sehyun Tak ◽  
Hwasoo Yeo
Keyword(s):  
Spatial Inhomogeneity ◽  
Microscopic Simulation ◽  
Fundamental Diagram ◽  
Traffic Dynamics ◽  
Simulation Experiments ◽  
Urban Networks ◽  
Urban Road ◽  
Macroscopic Fundamental Diagram ◽  
Transfer Flow ◽  
Supply Level

The aim of the concept of perimeter control is to manage the transfer flow between urban road networks. However, there is a lack of description on the behavior of transfer flow between networks in relation to the macroscopic fundamental diagram (MFD). Hence, this paper suggests a description of transfer flow and investigates it with microscopic simulation experiments. The results found that the network outbound demand strongly influences the outflow regardless of spatial inhomogeneity. Another finding is that the boundary capacity influences the network outflow. The effect of restriction on outflow of a network due to limited supply level of a neighboring network was also checked. Furthermore, it was found that a network’s inflow and outflow in each direction (north, south, east, and west) is proportional to the demand ratio. Finally, the suggested description of transfer flow has been confirmed, and this can be useful for various analyses on inter-network traffic dynamics.

Collection, Analysis, and Reporting of Kentucky Traffic Incident Management Performance

2021 ◽  
pp. 036119812110010
Author(s):  
Xu Zhang ◽  
Reginald R. Souleyrette ◽  
Eric Green ◽  
Teng Wang ◽  
Mei Chen ◽  
...  
Keyword(s):  
Motor Vehicle ◽  
Management Strategies ◽  
Incident Management ◽  
Vehicle Crashes ◽  
Clearance Time ◽  
Emergency Responders ◽  
Traffic Incident ◽  
Choropleth Maps ◽  
Traffic Incident Management ◽  
Secondary Crashes

Traffic incidents remain all too common. They negatively affect the safety of the traveling public and emergency responders and cause significant traffic delays. Congestion associated with incidents can instigate secondary crashes, exacerbating safety risks and economic costs. Traffic incident management (TIM) provides an effective approach for managing highway incidents and reducing their occurrence and impacts. The paper discusses the establishment and methods of calculation for five TIM performance measures that are used by the Kentucky Transportation Cabinet (KYTC) to improve incident response. The measures are: roadway clearance time, incident clearance time, secondary crashes, first responder vehicle crashes, and commercial motor vehicle crashes. Ongoing tracking and analysis of these metrics aid the KYTC in its efforts to comprehensively evaluate its TIM program and make continuous improvements. As part of this effort, a fully interactive TIM dashboard was developed using the Microsoft Power BI platform. Dashboard users can apply various spatial and temporal filters to identify trends at the state, district, county, and agency level. The dashboard also supports dynamic visualizations such as time-series plots and choropleth maps. With the TIM dashboard in place, KYTC personnel, as well as staff at other transportation agencies, can identify the strengths and weaknesses of their incident management strategies and revise practices accordingly.

Schedule-Constrained Demand Management in Two-Region Urban Networks

2021 ◽  
Author(s):  
Sakitha Kumarage ◽  
Mehmet Yildirimoglu ◽  
Mohsen Ramezani ◽  
Zuduo Zheng
Keyword(s):  
Nonlinear Optimization ◽  
Optimization Problem ◽  
Time Window ◽  
Demand Management ◽  
Urban Traffic ◽  
Fundamental Diagram ◽  
Constrained System ◽  
Nonlinear Optimization Problem ◽  
Management Platform ◽  
User Compliance

Demand management aiming to optimize system cost while ensuring user compliance in an urban traffic network is a challenging task. This paper introduces a cooperative demand redistribution strategy to optimize network performance through the retiming of departure times within a limited time window. The proposed model minimizes the total time spent in a two-region urban network by incurring minimal disruption to travelers’ departure schedules. Two traffic models based on the macroscopic fundamental diagram (MFD) are jointly implemented to redistribute demand and analyze travelers’ reaction. First, we establish equilibrium conditions via a day-to-day assignment process, which allows travelers to find their preferred departure times. The trip-based MFD model that incorporates individual traveler attributes is implemented in the day-to-day assignment, and it is conjugated with a network-level detour ratio model to incorporate the effect of congestion in individual traveler route choice. This allows us to consider travelers with individual preferences on departure times influenced by desired arrival times, trip lengths, and earliness and lateness costs. Second, we develop a nonlinear optimization problem to minimize the total time spent considering both observed and unobserved demand—that is, travelers opting in and out of the demand management platform. The accumulation-based MFD model that builds on aggregated system representation is implemented as part of the constraints in the nonlinear optimization problem. The results confirm the resourcefulness of the model to address complex two-region traffic dynamics and to increase overall performance by reaching a constrained system optimum scenario while ensuring the applicability at both full and partial user compliance conditions.

User Cost Analysis of UDOT’s Traffic Incident Management Program

2021 ◽  
Author(s):  
Mitchell G. Hadfield ◽  
Logan S. Bennett ◽  
Grant G. Schultz ◽  
Mitsuru Saito ◽  
Dennis L. Eggett
Keyword(s):  
Cost Analysis ◽  
Management Program ◽  
Incident Management ◽  
User Cost ◽  
Traffic Incident ◽  
Traffic Incident Management

Traffic Incident Duration Estimation Based on a Dual-Learning Bayesian Network Model

2018 ◽  
Vol 2672 (45) ◽  
pp. 196-209 ◽  
Author(s):  
Haozhe Cong ◽  
Cong Chen ◽  
Pei-Sung Lin ◽  
Guohui Zhang ◽  
John Milton ◽  
...  
Keyword(s):  
Bayesian Network ◽  
Expert Knowledge ◽  
Transportation Systems ◽  
Practical Significance ◽  
Incident Management ◽  
Highway Traffic ◽  
Traffic Incidents ◽  
Traffic Incident ◽  
Incident Duration ◽  
Traffic Incident Management

Highway traffic incidents induce a significant loss of life, economy, and productivity through injuries and fatalities, extended travel time and delay, and excessive energy consumption and air pollution. Traffic emergency management during incident conditions is the core element of active traffic management, and it is of practical significance to accurately understand the duration time distribution for typical traffic incident types and the factors that influence incident duration. This study proposes a dual-learning Bayesian network (BN) model to estimate traffic incident duration and to examine the influence of heterogeneous factors on the length of duration based on expert knowledge of traffic incident management and highway incident data collected in Zhejiang Province, China. Fifteen variables related to three aspects of traffic incidents, including incident information, incident consequences, and rescue resources, were included in the analysis. The trained BN model achieves favorable performance in several areas, including classification accuracy, the receiver operating characteristic (ROC) curve, and the area under curve (AUC) value. A classification matrix, and significant variables and their heterogeneous influences are identified accordingly. The research findings from this study provide beneficial reference to the understanding of decision-making in traffic incident response and process, active traffic incident management, and intelligent transportation systems.

Sign in / Sign up

Export Citation Format

Share Document