Mario Campanella

Effects of Heterogeneity on Self-Organized Pedestrian Flows

This investigation focuses on how the heterogeneity of pedestrian characteristics influences the buildup of congestion and affects the efficiency of pedestrian flows. Three commonly used parameters in pedestrian models–-desired speed, body size, and reaction time–-were varied in the population. Real pedestrian flows are heterogeneous regarding pedestrian characteristics. However, not much is known about the way that affects the qualities of the flow and how important it is to the outcomes of microsimulation models. The NOMAD model developed by Delft University of Technology is used to perform simulations in which the aforementioned heterogeneity is introduced. The investigation was carried out by creating bidirectional flows with fixed demands. The flows were analyzed by observing the development of breakdowns, average speeds, and average densities for different demands. It is shown that the influence of heterogeneity on breakdown probabilities and flow efficiency is considerable. To investigate this further, the dynamic lane formation process is investigated in detail. In addition to further insights into the causes for breakdown, it is found that the number of lanes increases with the decrease in heterogeneity in desired speed and in body size. However the opposite happens for heterogeneity in reaction time. Results indicate that heterogeneity in the population has a large impact on the flow quality and should be included in models explicitly to improve prediction performance.

Quantitative and Qualitative Validation Procedure for General Use of Pedestrian Models

This paper proposes a simple validation procedure that combines qualitative and quantitative assessments. The aim is to simplify the task of validation and still produce reliable results. By applying the procedure to the Nomad microscopic model it was revealed that parameter sets calibrated with flows that expose pedestrians to different situations and optimized with several calibration assessments (multi-objectives) are more accurate and present more realistic pedestrian behaviour. It also showed that for some parameter sets the model performed significantly better when simulating unidirectional flows than bidirectional flows or than a congested flow through a bottleneck. This result implies that validations using only one type of flow (especially if it is a unidirectional) are not reliable in respect of the general use of the parameter set.

Fundamental Diagrams for Pedestrian Networks

This paper explores the concept of the Network Fundamental Diagram for two-dimensional pedestrian networks. In doing so, we investigate if the average performance of the network can be described as a function of the average density or accumulation of the network, in line with recent findings on discrete vehicular traffic networks. We show that this is indeed the case, by considering data from walking experiments and from simulation using a microscopic pedestrian model. It turns out that the shape of the diagram is determined by a number of factors, such as the shape and size of the area, its use and its function, and the composition of the pedestrian flow. Finally, we propose several applications of the diagram for pedestrian networks.

Improving the Nomad microscopic walker model

Abstract This paper presents the results of two calibration efforts and improvements of the Nomad microscopic walker model. Each calibration consisted in comparing the outcome of 19 sets of model parameters with results from laboratory experiments. Three different flows were used in the calibrations: bidirectional, unidirectional and a narrow bottleneck. For the first two types of flow the macroscopic speed-density relation is used for comparison. For the narrow-bottleneck the capacity for the bottleneck is assessed. Additionally, quantitative measures of self-organizing lane formation for the bidirectional flow are included in the calibration. In the first calibration effort only 4 parameter sets did not present gridlocks in the bidirectional flow and their results are presented. These four sets over estimated the capacity of the bottleneck and the efficiency of the unidirectional flows. These results are discussed and it is shown that a modification in the model is necessary. A modified model is presented and submitted to a new round of calibration. One parameter set showed significant improvement for the speed-density relations and the capacity of the bottleneck. The experience gained in this calibration effort indicates that pedestrian microscopic models can be calibrated over several types of flows simultaneously. However, this research shows that care must be taken when using only macroscopic flow properties for calibration. They may not guarantee the generality of the model due to the complexity and variety of possible flows.

Interaction Behavior Between Individual Pedestrians

In this contribution, data on pedestrian interactions are analyzed stemming from newly performed laboratory experiments. It has been found that pedestrians perform interaction movements in 88 % of all occasions they meet another pedestrian. These interaction movements consist of lateral and/or longitudinal evasive maneuvers. For crossing situations the approach direction has no influence on the passing side. However, if the approach angle increases and the situation comes closer to bidirectional, pedestrians prefer passing each other on the right hand side. Walking in a hurry increases the probability of passing in front of another pedestrian. Meeting two pedestrians increases the probability of passing at the back. Pedestrians prefer larger lateral evasion in bidirectional situations and larger longitudinal evasion in crossing situations. Moreover, men laterally evade more than women and hurried pedestrians laterally evade more than normally walking pedestrians. Finally, the extent of evasion is larger when small groups are encountered.

Calibration of Nomad Parameters Using Empirical Data

This paper describes the results of calibration of the Nomad pedestrian simulation model using empirical data from laboratory experiments. The results of the calibration show that complex walker models with large amounts of parameters can indeed be calibrated. The estimated average parameter values are shown and discussed, as well as their significance and correlation. Furthermore, pedestrian behaviors are investigated using the estimated parameters values in various conditions, among which flow configuration, pedestrian heterogeneity and traffic conditions.

A methodology to calibrate pedestrian walker models using multiple objectives

The application of walker models to simulate real situations require accuracy in several traffic situations. One strategy to obtain a generic model is to calibrate the parameters in several situations using multiple-objective functions in the optimization process. In this paper, we propose a general methodology for calibration of walker models. This methodology is a generalisation of existing calibration procedures adapted to walker models. The fundamental aspect of the methodology is the use of several scenarios representing different calibration objectives. One of the advantages of the general methodology is that by applying it, the process of calibration helps understanding themodel and how to adjust it according to the intended application. As an example, the methodology is applied with synthetic generated trajectory data using the Nomad model to investigate the influence of the mathematical specifications of the objective functions and the flow configurations in the accuracy of estimations and significance of individual parameters.

Improving Pedestrian Micro-Simulations with Event Steps

Microscopic pedestrian models describe individual pedestrian behavior and the interaction of pedestrians with other pedestrians and obstacles. Continuous time models generally calculate the acceleration of pedestrians due to repulsive or attractive interactions using for instance distances to other pedestrians and obstacles within a two-dimensional influence area. Two problems that usually arise with these types of models when simulating very large crowds are extreme accelerations that occur due to very short distances to other pedestrians and obstacles and large computational times to assess and to calculate the accelerations for individual pedestrians. This paper presents a hybrid pedestrian management algorithm that combines a traditional optimized time-based simulation and an event-driven simulation. This way, the task of assessing the surroundings and the task of dealing with interactions on very short distances are each treated in an optimized way leading to more reliable accelerations in high densities as well as shorter calculation times.

Managing Large Flows in Metro Stations: The New Year Celebration in Copacabana

Around 2 million visitors visit the beach of Copacabana in Rio de Janeiro on New Years Eve every year. More than 100,000 visitors travel by Metro. This creates large pedestrian flows inside the station causing major discomfort due to crowding. With the steady increase of the flows in recent years a crowd management plan has been developed and applied to mitigate crowding problems. The plan identified the station as an open system with a feedback mechanism (crowd-management). The station system itself is connected to other systems such as the station surroundings and the trains. An offline analysis before the event identified the individual capacities of the station components, their dynamic properties, mutual influences and dependency to other systems. As a follow-up of these analyses, six crowd-management measures were. These measures and a new crowd-management plan enforced during the operations improved the safety and comfort of pedestrians during the 2012-2013 event. The bottlenecks were better understood and anticipated by their capacity increased causing significantly less crowding in the station and allowing a rapid action of marshals when an emergency occurred. The improved results obtained using few aspects of systems suggest that a methodology based on system engineering could be developed to plan and assess large crowds events.

Managing large flows in metro stations: Lessons learned from the New Year celebration in Copacabana

Around 2 million visitors reach the beach of Copacabana in Rio de Janeiro on the New Years Eve every year. More than 100.000 visitors travel by Metro and around 70% use the Cardeal Arcoverde Station (CAV) as their destination. This creates large pedestrian flows inside the station causing major discomfort and endangering the station users. With the steady increase of the flows in recent years a system engineering approach is applied to mitigate the circulation problems. The approach identified the station (and its components) as an open system with a feedback mechanism (crowd management measures). The system itself is connected to other systems such as the station surroundings and the trains. A system analysis, determined the individual capacities of the station components, their dynamic properties, mutual influences and dependency to the other systems. Based on these, crowd-management measures were devised and enforced in a contingency plan that improved the safety and comfort of pedestrians during the 2012-2013 event. The bottlenecks were better understood and their capacity improved causing significant less crowding in the station and allowing a rapid action of marshals when an emergency occurred. We conclude by showing the improved results that a system engineering approach is a useful approach to plan and access large crowds events.