Winnie Daamen

Experimental Research of Pedestrian Walking Behavior

To assess the design of walking infrastructure—such as transfer stations, shopping malls, sport stadiums, and others, as well as to support planning of timetables for public transit—tools to aid the designer are needed. To this end, microscopic and macroscopic pedestrian flow models can be and have been applied. To calibrate and validate such models, as well as to gain more insight into the characteristics of pedestrian flows under a variety of circumstances, detailed pedestrian flow data are required. Delft University of Technology has recently carried out experimental research of pedestrian flow. Described is the experimental design (such as determination of process variables and measurement), the resulting microscopic pedestrian data, and some initial results for the narrow bottleneck experiment. Both microscopic and macroscopic characteristics of the pedestrian flows are presented. Interesting first results pertain to the way in which the narrow bottleneck is used under saturated flow conditions, and the use of the space (or, rather, width) upstream of the bottleneck in case of congestion.

Investigating the Shape of the Macroscopic Fundamental Diagram Using Simulation Data

Macroscopic fundamental diagrams (MFDs) exist in large urban networks in which traffic conditions are homogenous. They can be used for estimation of the level of service on road networks, perimeter control, and macroscopic traffic modeling. However, before the MFD concept can be applied, the factors that influence the MFD shape should be identified and their effects investigated. A microscopic simulation model is used to change conditions, that is, to derive MFDs under different conditions and for different types of networks. Results indicate that a relationship indeed exists between production and accumulation for the whole network as well as for parts of the network focused on freeway or urban links. MFD shape is a property not only of the network itself but also of the applied traffic control measures. At the same time, congestion onset and resolution lead to heterogeneous traffic conditions with congestion at specific locations in the network, resulting in loops in congested parts of the MFD. Investigation of the effect of traffic demand on MFD also indicates that rapidly changing traffic demands drastically affect MFD shape.

Empirical Analysis of Merging Behavior at Freeway On-Ramp

The ability of microscopic (simulation) models to represent lane-changing behavior according to reality has recently been questioned. In this paper the merging maneuver (a specific type of lane changing) is analyzed with empirical data. First, a conceptual model is composed; it includes the factors influencing merging behavior, namely the merge location and its relation to prevailing driving conditions, gap acceptance, and the relaxation phenomenon. The empirical data set consists of 35 min of vehicle maneuvers on 400 m of freeway, collected by a camera mounted underneath a helicopter. This process results in a data set of 3,459 vehicle trajectories, from which 704 trajectories describe merging vehicles. It is found that different merge locations are used under congested and freeflow traffic conditions. During free-flow, most vehicles merge at the first half of the acceleration lane. Under congested traffic conditions, relatively more merges are registered at the end of the acceleration lane. The smallest accepted gap observed in the data set lies between 0.75 and 1.0 s. Net headways between the merging vehicle and the new leader and new follower of less than 0.25 s are recorded. These short accepted gaps are growing over time and indicate relaxation behavior. From the data analysis it can be concluded that gap acceptance theories, as they are used in current models and theories to model merge behavior, are not able to model the observed behavior accurately.

Self-Organization in Pedestrian Flow

Microscopic simulation models predict different forms of self-organization in pedestrian flows, such as the dynamic formation of lanes in bi-directional pedestrian flows. The experimental research presented in this paper provides more insight into these dynamic phenomena as well as exposing other forms of self-organization, i.e. in case of over-saturated bottlenecks or crossing pedestrian flows. The resulting structures resemble states occurring in granular matter and solids, including their imperfections (so-called vacancies). Groups of pedestrians that are homogeneous in terms of desired walking speeds and direction appear to form structures consisting of overlapping layers. This basic pattern forms the basis of other more complex patterns emerging in multi-directional pedestrian flow: in a bi-directional pedestrian flow, dynamic lanes are formed which can be described by the layer structure. Diagonal patterns can be identified in crossing pedestrian flows. This paper both describes these structures and the conditions under which they emerge, as well as the implications for theory and modeling of pedestrian flows.

Microscopic Calibration and Validation of Pedestrian Models: Cross-Comparison of Models Using Experimental Data

This contribution proposes a new approach to estimate model parameters of microscopic pedestrian models using individual pedestrian trajectory data. To this end, a generic approach is proposed that enables parameter identification for microscopic models in general and in particular for walker models. The application results provide new insight into the behavior of individual pedestrians, inter-pedestrian differences, as well as the resulting pedestrian flow characteristics. By comparing different models of increasing complexity, it is investigated which of the model amendments are significant from a statistical point of view and which are not. It is shown that besides anisotropy, finite reaction times play an important role in correctly describing microscopic walking behavior. The implications of these findings in the microscopic description of pedestrians flows are considered by studying the predicted flow operations at a narrow bottleneck. It turns out that the finite reaction times have a significant effect on the pedestrian flow operations.

Eco-routing: Comparing the fuel consumption of different routes between an origin and destination using field test speed profiles and synthetic speed profiles

Eco-routing is the identification of the most energy-efficient route for a vehicle to travel between two points and is offered as a way in which drivers can reduce fuel consumption and consequently reduce the carbon footprint of their journeys. This paper covers the first step in the process of investigating the impacts of digital map attributes on the calculation of an eco-route. A research tool is developed in which historical link speed data is used as a basis for replicating vehicle speed profiles, enabling the calculation of fuel costs per link. These fuel costs and speed profiles are validated by field test data. The results show that synthetic speed profiles created using the research tool differ from those measured in the field test. They also demonstrate that the characteristics of a route are influenced by location-based attributes, indicating that map attributes that are used to create more representative speed profiles do indeed have the potential to be used in the calculation of eco-routes.

Boarding and Alighting Experiments: Overview of Setup and Performance and Some Preliminary Results

Vehicle dwell time is an important determinant of the system performance and passenger service quality of public transport systems. Adequate prediction models for vehicle dwell time are required in timetable planning and in pedestrian simulation tools to optimize station design and rolling stock design. Because most of the dwell time is consumed by boarding and alighting, this paper focuses on increasing insight into boarding and alighting behavior in railroad vehicles by performing laboratory experiments using video cameras. The experiments test the effects of the physical environment (stepping gap, height difference, and door width), population (age, gender), flow composition (direction, time pressure, luggage, boarding group size, boarding ratio, queuing discipline), and prevailing traffic conditions (crowding on board and crowding on the platform). From the video images, pedestrian trajectories (movements over time) have been derived. This paper describes the effects of the size of the horizontal and vertical gap and the presence of luggage on the door capacity. Door capacities have been estimated by using headway distributions and cumulative curves. Increasing the horizontal and vertical gap leads to decreases in the capacity (up to 15%). When passengers with luggage (suitcases) are present, the capacity decreases more (up to 25%).

First-order pedestrian traffic flow theory

This paper discusses the validity of first-order traffic flow theory for the description of two-dimensional pedestrian flow operations in the case of an oversaturated bottleneck in front of which a large high-density region has formed. The paper shows how observations of density, speed, and flow that have been collected from laboratory walking experiments can be interpreted from the viewpoint of first-order theory. It is observed that pedestrians present at the same cross section inside of the congested region may encounter different flow conditions. This mainly depends on the lateral position of the pedestrian with respect to the center of the congested region. In the lateral center, high densities and low speeds are observed. However, on the boundary of the congested region, pedestrians may walk in nearly free-flow conditions and literally walk around this congested region. Visualization of these data in the flow-density plane results in a large scatter of points that have similar flows (bottleneck capa...

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.

Influence of changes in level on passenger route choice in railway stations

In assessing the design of a public transfer station, it is important to be able to predict the routes taken by passengers. Most simulation tools use simple route choice models that take into account only the shortest walking distance or walking time between a passengers origin and destination. To improve this type of route choice model, other factors affecting passenger route choice need to be identified. Also, the way these factors influence route choice behavior needs to be determined to indicate how each factor is valued. In this research, route choice data have been collected in two Dutch train stations by following passengers through the facility from their origins to their destinations. These data have been used to estimate extended route choice models. The focus is on the influences of level changes in walking routes on passenger route choice behavior. It appears that ways of bridging level changes (ramps, stairs, escalators) each have a significant and different impact on the attractiveness of a...